Process to obtain a USY zeolite having a high mesoporosity

Abstract

The invention is directed to a process to obtain a mesoporous USY zeolite starting from a mildly steamed zeolite comprising the following steps: (i) contacting the zeolite Y with an aqueous solution comprising a carboxylate salt, of which at least 40 mol% and at most 80 mol% of the cations are protons and wherein the pH is in the range of 1 to 5 to obtain an treated zeolite Y; (ii) contacting the zeolite Y of (i) with a solid base or a base solution to obtain a treated zeolite Y; contacting the zeolite Y of step (ii) with an acid, (iii) contacting the zeolite Y of (ii) with an aqueous solution containing an ammonium salt and obtaining a ammonium zeolite Y; (iv) subjecting the zeolite of (iii) to a steam treatment to obtain a USY zeolite, and (v) contacting the USY of (iv) with an acid.

Description

[0001] PROCESS TO OBTAIN A USY ZEOLITE HAVING A HIGH MESOPOROSITY

[0002] The invention is directed to a process to obtain a USY zeolite having a high mesoporosity.

[0003] Within this description, the term ‘Y zeolites’ is used for faujasite zeolites with unit cell sizes equal to or larger than 24.45 Angstrom. Faujasite zeolites with unit cell sizes smaller than 24.45 Angstrom are referred to as ultra-stable Y zeolites, hereafter referred to as ‘USY zeolites’ or ‘USY’.

[0004] Catalysts comprising of USY zeolites are well known for use in hydrocracking processes of refinery feeds to middle distillates, such as gas oil and kerosene. More recently such catalysts are also used to hydroprocess bio-based feedstocks to middle distillates. It is found that when USY crystals are used having a high volume of mesopores and a high molar silica to alumina (SiO2 / Al2O3) ratio (SAR) in such hydroprocessing the selectivity to middle distillates improve.

[0005] Applicant’s US2023 / 0051097 describes in its example 71 a zeolite USY having a micropore volume of 0.28 ml g-1 and a mesopore volume of 0.33 ml g-1 . This zeolite USY is prepared from a low SAR USY CBV 712 from Zeolyst International. The disclosed mesoporous zeolite USY has a SAR of about 12 or lower.

[0006] US2022073359 describes a process to prepare low silica to alumina ratio (SAR) mesoporous zeolite Y starting from a parent zeolite-Y which has been subjected to a mild steam treatment. In the process the parent zeolite is gradually contacted with an acid to obtain an intermediate acid-treated zeolite Y. Subsequently the intermediate acid-treated zeolite Y is contacted with a solid base or a base solution to obtain the low SAR mesoporous zeolite Y.

[0007] Processes to yield high-SAR mesoporous USY crystals are characterised in that a USY with unit cell size below 24.45 Angstrom and molar SiO2 / Al2O3 ratio above typically 12 mol / mol, are exposed to a base treatment. M. Milina et al. in Catalysis Today, 2014, 235, 176-183 describe a zeolite USY having SAR between 20 and 30 and a high micropore volume and mesopore volume, derived from a parent USY zeolite of high SAR of 35 by using alkaline treatments with organic additives.

[0008] Keller et al. in ACS Catal. 2015, 5, 2, 734-743, describe a variety of mesoporous USY zeolites having SARs between 10 and 78, prepared by mesoporisation of parent USY zeolites of high SARs between 12 and 80 using alkaline treatments with organic additives.

[0009] Verboekend et al. Cryst. Growth. Des., 2012, 12, 6, 3123, 3132, describe various mesoporous USY zeolites of high micropore volume, mesopore volume and high crystallinity, prepared by mesoporisation of a parent USY with SAR of 60, using alkaline treatments with organic additives. In this work, crystallinity was assessed on USY zeolites in the sodium form.

[0010] US5601798 describes a process wherein Y or USY zeolites are exposed to a single hydrothermal treatment in the presence of acid, bases, and / or salts, in the pH range of 4.5-10.

[0011] US20130292301 describes a mesoporisation of a steamed and acid treated USY having a silica to alumina ratio of about 60 by leaching with a sodium hydroxide aqueous solution in the absence of protective agents. The selectivity to middle distillates in a hydrocracking experiment of the catalyst containing the mesoporous USY was higher as compared to when a catalyst is used containing the conventional USY. The activity of the catalyst containing the mesoporous USY was much lower than the activity of the catalyst containing the conventional steamed USY in the hydrocracking reaction.

[0012] WO2021 185721 describes a mesoporisation of parent USY zeolites with SARs of 30, 60 and 80 using sodium hydroxide and cetyltrimethylammonium chloride (CTAC) as protective agent. When the modified USY zeolites are used as part of a hydrocracking catalyst an improvement is reported for middle distillate selectivity at a reduced catalytic activity. This publication shows that, at similar zeolite loading, the catalyst activity in hydrocracking decreased when the SAR of the zeolite increased. WO2021185721 further describes that the use of cetyltrimethylammonium chloride (CTAC) could result in safety issues in the subsequent calcination step. According to this publication, this safety issue, namely risk of explosion during calcination, is mitigated by performing the calcination on a shaped catalyst carrier comprising of the modified USY and a binder.

[0013] The above processes make use of a USY having a relatively high sil ica-to- alumina ratio (SAR). Such high-SAR USY crystals are derived from post-synthetic upgrading of hydrothermal ly-synthesized low-SAR Y zeolites. Y zeolites obtained by hydrothermal crystallization have a relatively low silica-to-alumina ratio of 4-7 mol / mol, a low mesopore volume, and are in the sodium from. Such Y zeolites are also referred to as ‘NaY’ zeolites. These NaY zeolites are characterised by a unit cell size in the range of 24.60 to 24.70 A. Various processes have been developed to increase the molar silica to alumina ratio (SAR) of zeolite-Y crystals. Processes to increase the SAR typically involve a severe steam treatment, at temperatures of above 600°C, followed by an acid treatment. Steam and acid treatments typically result in some increase in mesoporosity yielding mesopore volumes in the range of 0.15 to 0.25 ml / g. When higher mesopore volumes are desired the thus obtained high SAR USY is subjected to a base treatment as for example described in the above referred to publications.

[0014] A disadvantage of the application of base treatments to high-SAR USY zeolites, as for example described in the above referred to publications, is that a protective agent is required. Protective agents such as tetrapropylammonium or cetyltrimetylammonium protect the fragile high-SAR faujasite structure in the alkaline media of the base treatment. In the case protective agents are not used, USY zeolites with SARs over 15 tend to strongly amorphize leading to reduced acidity and activity in catalytic reactions. This is most likely the cause that at similar zeolite loading the catalyst activity in hydrocracking decreased when the SAR of the zeolite increased as reported in WO2021185721 . The requirement to use protective agents results in that these compounds need to be removed from the USY zeolite at some point in the process. Such a removal is typically by means of combustion resulting in undesired explosivity risks and undesired CO2 and NOXemissions. The use of protective agents could for example result in safety issues in the subsequent calcination step as described in WO2021185721 for cetyltrimethylammonium chloride (CTAC). According to this publication, a safety issue, namely risk of explosion during calcination, is mitigated by performing the calcination on a shaped catalyst carrier comprising of the modified USY zeolite and a binder.

[0015] When increasing the volume of mesopores in USY crystals it is desired to maintain a high pore volume of micropores within the crystals. This because most of the catalytic activity will take in the micropores of the USY crystal, while the mesopores serve to efficiently transport the feed and the cracked products to and from these micropores. Further it is desired that the USY crystalline nature is maintained in the process. Not all protective agents enable to maintain the crystalline structure to the same extent. For example, tetrapropylammonium cations (TPA) tend to yield highly-crystalline USY materials upon base treatment (Cryst. Growth Des. 2012, 12, 6, 3123-3132). In contrast, micelle-forming tetraalkylammonium cations, such as CTA as described in WO2021185721 , typically yield a significant reduction in intrinsic zeolitic properties, such as crystallinity. This can be explained by the tendency of micelle-forming tetraalkylammonium cations to form amorphous phases, such as MCM-41 , in alkaline media in the presence of dissolved aluminosilicates. Such an amorphous phase can also display significant microporosity (Catalysis Letters 49, 1997, 147, 153). However, these non-ordered amorphous micropores do not beneficially contribute to the catalytic activity of the catalyst.

[0016] Similarly, it is imperative that during the introduction of mesopore volume, the density of Bronsted acid sites and the acid strength of the zeolite is not negatively influenced. High SAR USY zeolites typically have a good acid strength for use as part of a hydrocracking catalyst. The impact of alkaline treatment on the acidity of the high-SAR USY depends on the nature of the applied treatment. For example, in the absence of protective agents, a reduction in Bronsted acid density is typically observed in combination with a reduction of acid strength. Also, when micelleforming tetraalkylammonium cations are used in the alkaline treatment, the resulting solid, likely featuring MCM-41 -type of materials, typically displays a reduction of Bronsted acidity and a reduction of acid site strength. Protective agents such as TPA enable to preserve the Bronsted acid density. However, also protective agents such as TPA yield a reduction in acid strength. Hence, it is commonly accepted that when a high-SAR USY is mesoporised via a base treatment the acid strength is reduced.

[0017] It is thus an object of the present invention to provide for a process to obtain a USY zeolite having a high SAR and an improved mesopore volume while maintaining a high micropore volume.

[0018] This object is achieved by the following process. Process to obtain a USY zeolite having a high mesoporosity starting from a parent zeolite-Y with a unit cell in the range of 24.45 to 24.60 A and having a SiO2 / Al2O3 ratio of between 4 and 8 mol / mol, comprising the following steps:

[0019] (i) contacting the parent zeolite Y with an aqueous solution comprising a carboxylate salt, of which at least 40 mol% and at most 80 mol% of the cations are protons and wherein the pH is in the range of 1 to 5 to obtain an intermediate acid-treated zeolite Y,

[0020] (ii) contacting the intermediate acid-treated zeolite Y with a solid base or a base solution to obtain an intermediate acid-alkaline-treated zeolite Y, (iia) wherein the obtained intermediate acid-alkaline-treated zeolite Y of step (ii) is subjected to an additional acid treatment step (iia) by contacting the intermediate acid-alkaline-treated zeolite Y of step (ii) with an aqueous solution comprising a carboxylate salt, of which at least 40 mol% and at most 80 mol% of the cations are protons, and wherein the pH is in the range of 1 to 5 to obtain an intermediate acid-alkaline-acid-treated zeolite Y,

[0021] (iii) contacting the intermediate acid-alkaline-acid treated zeolite Y with an aqueous solution containing an ammonium salt and obtaining a zeolite Y in the ammonium form,

[0022] (iv) subjecting the zeolite Y in the ammonium form to a steam treatment to obtain an intermediate steam modified USY zeolite, and (v) contacting the intermediate steam modified USY zeolite with an acid to obtain the USY zeolite having a high mesoporosity.

[0023] Applicants found that with this process a USY zeolite having a high SAR and a high mesoporosity can be obtained while maintaining a high crystallinity and a high micropore volume in the zeolite USY crystals. A high SAR USY zeolite may be obtained having a high crystallinity and wherein less of the zeolite is amorphized in the process. Without wanting to be limited by the following theory, it is believed that this results from the fact that the base treatment, as takes place in step (ii), is performed prior to the steam and dealumination steps (iv and v). In the prior art processes, as for example described in Chem. Mater, 2014, 26, 4552-4562, a mesoporisation treatment is performed on a high-SAR parent by treatment of a high- SAR parent in an alkaline media. It is found that especially for high SAR USY zeolites of between 40 and 80 amorphization of the crystalline phase takes place in such an alkaline treatment which is avoided by the present process. Because of the higher crystallinity at high SAR a more active hydrocracking catalyst will be obtained when using the USY zeolite as prepared by this process.

[0024] The invention is also directed to the following USY zeolite as obtainable by the inventive process.

[0025] A USY zeolite having a micropore volume greater than 0.24 ml / g, a mesopore volume greater than 0.30 ml / g, and a SiO2 / Al2O3 ratio (SAR) greater than 40 mol / mol, a unit cell size smaller than 24.45 A, and a relative crystallinity of at least 40 % relative to a NaY.

[0026] Applicants found that the intermediate Y zeolites prepared by steps (i), (ii), (iia) and (iii) of this process have unique properties making them suited for preparing the above USY. For this reason, the invention is also directed to the following first intermediate zeolite Y in the ammonium form as obtainable in step (iii) of the inventive process. An intermediate Y zeolite in the ammonium cation form having a micropore volume greater than 0.28 ml / g and a mesopore volume greater than 0.15 ml / g as measured by nitrogen physisorption, a SiO2 / Al2O3 ratio of 5 to 12 mol / mol, a unit cell size smaller than 24.55 A and larger than 24.45 A, a total surface area greater than 700 m2 / g, a NAR below 0.15, and a relative crystallinity of at least 75 % relative to a NaY.

[0027] The invention is also directed to a process to prepare the above first intermediate wherein the process of this invention is performed except that steps (iv) and (v) are not performed. The invention is also directed to the use of this intermediate Y zeolite to prepare the inventive USY zeolite by performing a process comprising a step (iv) and step (v) as described for the inventive process.

[0028] The invention is also directed to a second intermediate zeolite USY obtainable in step (iv) of the inventive process. In the step (iv) a USY zeolite is obtained. The invention is thus directed to:

[0029] An intermediate USY zeolite having a micropore volume greater than 0.17 ml / g and a mesopore volume greater than 0.30 ml / g, a SiO2 / Al2O3 ratio of 5 to 10 mol / mol, a unit cell size smaller than 24.45 A, a total surface area greater than 500 m2 / g, and a relative crystallinity of at least 35 % relative to a NaY.

[0030] The invention is also directed to a process to prepare the above second intermediate wherein the process of this invention is performed except that step (v) is not performed. The invention is also directed to the use of this intermediate USY zeolite to prepare the inventive USY by performing a process comprising a step (v) as described for the inventive process.

[0031] A further advantage is that the obtained USY has a similar or higher acid strength when compared to a corresponding USY which has not been subjected to a mesoporisation treatment. A further advantage is that the process can be performed without having to use protective agents. Inventors have found that there exists a synergy between steps (i), (ii) and (iia) and steps (iv) and (v). This synergy makes that after the application of the inventive process less solid material is lost and less waste water is generated as compared to the state of the art mesoporisation processes when preparing a USY having the same degree of mesoporosity. This synergy can be illustrated by the step wise increase of mesoporosity in the various steps. Typically, steps (i) and (ii) and (iia) result in the formation of about 0.10-0.50 ml / g of mesopore volume, which is increased, if done according to this invention, by 0.10 to 0.30 ml / g in steps (iv) and (v). This amplification of the mesopore volume of low SAR faujasite mesoporous zeolites before performing a steaming and acid treatment is not known in the state of the art. For example, known steam treatments applied to mesoporous low SAR zeolites did not result in an increase in mesoporosity and sometimes even in a reduction of mesoporosity as described in Catal. Sci. Technol., 2013, 3, 972-981.

[0032] A next advantage is that the high energy demanding steam step (iv) is performed after the acid and base treatments of steps (i) and (ii). In this way the energy demanding step is only applied for the almost finished product. In the prior art processes the steaming is applied to prepare the starting USY zeolite on which the base treatment is subsequently applied. In such a base treatment, as in step (ii), starting zeolite is lost due to dissolution, which makes that the energy required to produce the dissolved parent zeolite is also lost. In contrast, in the process of this invention, zeolite Y lost by dissolution in step i) and step ii) has not been subjected to a severe steam contacting. Thus, the process of this invention requires less steam per unit mass of mesoporous USY zeolite product as will be illustrated below.

[0033] A further advantage of the process of this invention is that no ion exchange needs to be executed on the USY zeolite, hence the faujasite obtained after severe steaming. In the state of the art mesoporisation processes are executed on USY zeolites, which have already been dealuminated by ion exchange, steaming, and acid treatment of a starting zeolite NaY. The resulting USY zeolite is subsequently subjected to a base treatment, typically using a mineral base, such as NaOH. In such a base step the USY zeolite undergoes a concomitant ion exchange. When NaOH is used in the state of the art processes the obtained mespororous USY zeolite will be in the sodium form. A USY zeolite in the sodium form is however not catalytically active. For this reason, a second ion exchange is required to bring the USY zeolite to the catalytically active ammonium or protonic form. By using the process of this invention no ion exchange step is required after the severe steaming. Moreover, even after ion exchange, the state in the art processes feature, unlike materials by this invention, relatively large amounts of undesired residual sodium.

[0034] In this description the term mesoporisation, mesoporisation treatment or mesoporisation process refers to a treatment or process wherein the volume of the mesopores of a zeolite is increased relative to the volume of the mesopores of a starting parent zeolite. The volume of the mesopores of a zeolite is referred to as the mesopore volume (Vmeso).

[0035] The solid yield, or yield, of a treatment refers to the amount of solid at the end of a treatment after drying, that is, corrected for humidity, and is expressed as the percentage compared to the amount of zeolite sample introduced into the treatment at the beginning. The initial amount of zeolite is also corrected for humidity content. Humidity content is assessed via a moisture analyser operated at 180 °C.

[0036] The molar ratio of silica to alumina also referred to as SiO2 / Al2O3 ratio or SAR of the zeolite is measured using X-ray fluorescence (XRF) and is expressed in mol / mol. The references in the description to bulk SAR or SAR relate to the same property.

[0037] The unit cell size (UCS) is measured by X-ray diffraction as described by the method of ASTM D3942-19.

[0038] The pore volume (Vpore) is measured by nitrogen physisorption at 77 K taking the volume adsorbed at relative pressure of 0.99.

[0039] The micropore volume (Vmicro) relates to the porosity in the size range from zero to ca. 2 nm of the pores in the zeolite crystal. This micropore volume includes both the zeolitic micropore volume of around 0.6-0.8 nm and any non-zeolitic microporosity related to amorphous species, such as SBA-15 and MCM-41 , typically in the range of 1-2 nm. Such a standard measurement is by application of the t-plot to the adsorption branch of the nitrogen physisorption isotherm obtained at 77K in a range of partial pressure P / PO comprised between 0.075 and 0.30 as described by the method of ASTM D4365-19. In most prior art references such a standard micropore volume is disclosed.

[0040] Micropore volume analysis can also be measured using high-resolution low- pressure argon sorption at 87 K as described in Studies in Surface Science and Catalysis, Volume 170, 2007, Pages 1042-1047. Argon sorption enables a more accurate analysis of the microporosity, and can help to distinguish between zeolitic and non-zeolitic microporosity. Herein, the micropore volume measured by argon (Vmicro-Ar) relates to the porosity of the crystalline phase of the zeolite in the size range from zero to ca. 1 nm of the pores. This micropore volume measured by argon (Vmicro-Ar) does not relate to the micropores of any non-zeolitic microporosity related amorphous species, such as SBA-15 and MCM-41. In this specific method the micropores of the crystalline phase of the zeolite are saturated at a pressure of 0.004 with argon at 87 K. The micropore volume (Vmicro-Ar) relates to the total volume of argon sorbed at relative pressure of 0.004. Prior to the sorption experiments, the samples are outgassed for 12 h under turbomolecular pump vacuum at 350°C. Unlike the micropore volume determined using nitrogen sorption at 77 K (Vmicro), The micropore volume as determined using argon sorption at 87 K (Vmicro-Ar) is expressed in ml / g at standard temperature and pressure (STP).

[0041] The mesopore volume (Vmeso) of the zeolite refers to the volume of pores having a diameter in the range of 2 to about 50 nm. The mesopore volume (Vmeso) is obtained by subtracting the micropore volume from the pore volume (hence Vmeso = Vpore - Vmicro), both obtained by nitrogen physisorption at 77 K as described above.

[0042] The total surface area (SBET) is measured by the BET adsorption method of ASTM D4365-19 in a range of partial pressure P / P0 comprised between 0.05 and 0.30. The molar soda (Na2O)-to-alumina (AI2O3) ratio is referred to as the NAR, and describes the relative amount of soda left with respect to the theoretical maximum amount of acidity in the zeolite. Since sodium has a negative impact in hydrocracking, the NAR of suitable USYs should be as low as possible. The Na2O content is measured using X-ray fluorescence (XRF).

[0043] The relative crystallinity, also referred to as RC, of a Y or USY zeolite relative to a NaY is measured via ASTM 3906. This test method provides a number that is the ratio of intensity of portions of the XRD pattern of the sample to intensity of the corresponding portion of the pattern of a reference zeolite, NaY. This number is the relative crystallinity of a Y or USY zeolite relative to a NaY.

[0044] When reference is made to the acid strength of the USY zeolite the Bronsted acidity as measured by desorption of pyridine at 350°C is meant and is referred to as B350. The Bronsted acidity of the USY zeolite is measured by Fourier Transformed Infrared spectroscopy (FTIR) after adsorption to saturation and partial desorption of pyridine as described in Section A of this description. The area of the characteristic band of pyridine protonated at 1545 cm-1 correlates to the amount of Bronsted acidity of the USY zeolite expressed as pmol Bronsted adsorbed pyridine per grams of USY zeolite. The Bronsted acidity as measured by desorption of pyridine at 350°C relates to the strong acid sites as present in the USY zeolite. When for example the Bronsted acidity would be measured at relatively low temperature, such as 150°C, all weak and strong acid sites are probed with pyridine.

[0045] The molar ratio between B350, expressed in mol per gram of zeolite, and the aluminum content, expressed in mol Al per gram of zeolite, results in a descriptor ‘B350 / AI’ expressed in mol / mol, and is a measure for the acid strength of a USY zeolite.

[0046] Section A

[0047] Herein, the Lewis and Bronsted acidity of zeolitic materials is measured by Fourier Transformed Infrared spectroscopy (FTIR) after adsorption to saturation and partial desorption of pyridine. The area of the characteristic band of pyridine coordinated at 1455 cm_1 correlates to the amount of Lewis acidity of a zeolite powder or catalyst extrudate expressed as pmol Lewis adsorbed pyridine per grams of USY zeolite. Similarly, the area of the characteristic band of pyridine protonated at 1545 cm_1 correlates to the amount of Bronsted acidity of a zeolite powder or catalyst extrudate expressed as pmol Bronsted adsorbed pyridine per grams of USY zeolite. The procedure and calculation used to derive the amount of Lewis and Bronsted acidity based on the FTIR measurements are well known to the skilled person and are for example described in J. Catal., 1993, 141 , 347-354 or Journal of Catalysis 385 (2020) 52-60.

[0048] Changes in desorption temperature enable to vary the degree of desorption and hereby monitor the relative strength of the probed acid sites. For example, at relatively low temperature, such as 150°C, all acid sites are probed with pyridine, whereas at relatively high temperature, such as 350°C, only the strong acid sites remain probed with pyridine. Acidity types and strengths are indicated herein using a ‘B’ to indicate Bronsted acidity. As such, ‘B350’ is the Bronsted acidity of the zeolite- Y as measured after pyridine desorption at 350 °C. Resulting values are in pmol per gram of zeolite.

[0049] A “classical” in situ infrared cell is used as described in Journal of Catalysis 385 (2020) 52-60, with the option to heat the lower measuring area. Figure 1 shows the classical configuration used to analyze the acidity of faujasites with pyridine adsorbed using in situ infrared spectroscopy. (1 ) Connection to vacuum. (2) Quartz sample holder (able to be lowered to the dashed circle position). (3) Upper heating element. (4) Sample wafer. (5) Quartz body of the cell. (6) Lower heating element. (7) Incoming infrared signal. (8) KBr windows. (9) DTGS Detector. The applied working method follows the recommendations set out in said work and follows the following steps:

[0050] A first step to measure the zeolite’s acidity using FTIR spectroscopy using pyridine as probe molecule regards the making of the self-supported wafer or disc through which the IR signal travels. These are made from free-flowing powders, with particle size in the range of 1-10 pm, which are compressed into self-supported wafers or discs with cross-section surfaces of 1 -3 cm2 of homogeneous thickness, using an hydraulic press and a die, with the amount of sample ranging from 5-15 mg per cm2,usjngapressure of at most 500 kgs per cm2. The weight of the wafer is noted and corrected for weakly adsorbed water in the range of room temperature to 200°C.

[0051] The second step regards the placement of the wafer into the body of the cell, followed by the activation, also referred to as ‘degassing’, by heating to 400°C using a ramp of 25 °C / min, a dwell time of 12 h, and application of a dynamic vacuum better than 0.01 mbar. After this activation, the sample is cooled down to 150°C, at which point a reference spectrum (Ref. Spect.) is acquired. Afterwards the sample is cooled down to 50°C.

[0052] Next, the sample is saturated at 50°C with pyridine (>99.5% pure and dried), by introducing pulses of 10 mbar of pyridine into the volume of the cell until the sample is saturated. Saturation is followed by evaluation of the Bronsted peaks in the FTIR spectrum, and is typically reached using 10 pulses of 1 min each. Next, physisorbed pyridine species are removed by heating the cell to 150°C using a ramp of 25 °C / min and application of the vacuum, and a dwell time of 120 min. Next, the temperature is increased to 350 °C using a ramp of 25 °C / min, combined with a dwell time of 60 min, followed by cooling down to 150 °C, after which the spectrum ‘350 Spect.’ is acquired. The obtained spectra after adsorption and desorption of pyridine are subsequently corrected by subtraction of the reference spectrum (Ref. Spect.), yielding a 350 Calc. Spect.

[0053] Subtraction of the corresponding Ref. Spect from the 350 Spect. is executed differently from other zeolites such as ZSM-5. This is because, activated high-SAR pyridine-free parent USY zeolites feature a peak around 1550 cm_1 . This peak overlaps with the peak associated to pyridine adsorbed to Bronsted acid sites (see also Microporous and Mesoporous Materials 299, 2020, 110114). If not corrected for by the aforementioned subtraction, this peak overestimates B350 by about 50-80 pmol / g. Spectra are recorded using a commercially available FTIR spectrometer equipped with industry standard deuterated triglycine sulfate (DTGS) detector, as may be obtained from Nicolet or Thermo, in the range of 6000-1000 cm_1 , at a spectral resolution of 4 cm_1 and 64 scans in transmission mode. Integration of the peak areas is done using peak limits for Bronsted acidity of 1565-1515 cm_1 (yielding B350), a baseline between those peak limits using specialized spectrometer software called Omnic from Thermo.

[0054] The obtained peak areas are converted into a number of acid sites (nPy in pmol) using the Lambert-Beer equation: A=£(nPy / S), wherein ‘A’ is the peak area in cm_1 , ‘s’ the integrated extinction coefficient in cm / pmol, ‘S’ the surface area of the cross section of the wafer or disc, in cm2. The extinction coefficients as reported in J. Catal. 1993, 141 , 347-354 are used, being 1.67 cm / pmol for Bronsted. This results for the Bronsted acid sites in: nB=(SxAB) / 1.67, with nB, the number of measured Bronsted acid sites, in pmol, and AB the peak area of the related to Bronsted acidity, in cm-1 .

[0055] With nB known, the weight-based Bronsted acid site density (in pmol per gram), B, is obtained by dividing by the weight of the wafer or disc: B = nB / w, wherein ‘w’ is weight of the wafer or disc, in g, on dry basis. The Bronsted acid site density after pyridine desorption at 350°C, is designated as ‘B350’.

[0056] Table A:

[0057] End of Section A The parent zeolite Y has a unit cell in the range of 24.45 to 24.60 A. Such a parent zeolite may be obtained starting from a NaY zeolite wherein the NaY zeolite is ion exchanged to its ammonium form followed by a mild steam treatment. The faujasite obtained directly after its hydrothermal crystallization is typically fully in the sodium form and is referred to as a ‘NaY’. More than 90 wt% of the aluminium of NaY is framework aluminum. An example of a NaY is CBV100 obtainable from Zeolyst International. Mild steam treatment is typically performed at temperatures below 550°C. The NaY zeolite is ion exchanged to its ammonium form, suitably using an aqueous solution of an ammonium salt. In this step about 80% the sodium is removed from the NaY zeolite, yielding a (NH4)o.sNao.2Y zeolite. An example of a (NH4)o.gNao.2Y zeolite is CBV300 from Zeolyst International. These zeolites have unit cell sizes larger than 24.60 Angstrom and are as such not suitable as parent zeolites for the current invention. The remaining 20% of sodium (ca. 2 wt%) in a (NH4)o.8NaQ 2Y zeolite is hard to remove from the zeolite using conventional ammonium exchanges as described in US5435987. In the mild steaming part of the residual sodium is released and about 50 wt% of the aluminum from the zeolite framework in converted into non-zeolitic (extra-framework) aluminum. This results in a reduction of the unit cell size to a value of between 24.45 and 24.60 Angstrom. The mild steaming yields Y zeolite mostly in the hydrogen form, a ‘HY’ zeolite and having a sodium content of about 2 wt%, and is suitable as parent for the present invention. Example of such a preferred mildly-steamed zeolite Y in the protonic form and featuring about 2 wt% of sodium is CBV400 from Zeolyst International. Another suitable parent zeolite Y for this invented process is a zeolite Y obtainable starting from the above HY zeolite wherein the HY zeolite is subjected to a standard ammonium ion exchange, reducing the sodium content a level of about 0.2 wt% in the obtained NH4Y zeolite. This NH4Y zeolite is also a suitable parent zeolite. Example of such a mildly steamed and ammonium ion exchanged zeolite is CBV500 from Zeolyst International. When preparing a USY, not according to this invention, this NH4Y zeolite is typically severely steamed to obtain a USY with a unit cell size of below 24.45 Angstrom, such as CBV600 from Zeolyst International. In contrast, for the present invention, severe steaming is executed only after steps (i-iii) and the parent zeolite Y for use in step (i) of the invented process can therefore be in any cation form.

[0058] The parent zeolite Y has a unit cell in the range of 24.45 to 24.60 A may also be prepared by exposing Y zeolites with unit cell sizes of between 24.60 and 24.70 Angstrom to a calcination treatment and / or by an acid treatment. The calcination treatment is suitably performed in the absence of water and at a temperature of between 500-700°C. The acid treatment is suitably performed by contacting the zeolite with a fully protonic organic or mineral acid. When both a calcination and an acid treatment is performed it is preferred that acid treatment is executed after the calcination.

[0059] The parent Y zeolites have a relatively low SiO2 / Al2O3 ratio (SAR) of between 4 and 8 mol / mol and preferably between 5 and 7 mol / mol. The parent zeolite Y has a content of aluminum as part of the framework of at least 10 % relative to the total amount of aluminium in the bulk as assessed by AI27 MAS NMR, preferably above 20 %, more preferably above 30%, most preferably above 40%, preferably below 90%, more preferably below 80%, and most preferably below 70% or even below 60%. Preferred parent zeolite Y has a low mesopore volume and suitably in the range of between 0.02 and 0.10 ml / g. Preferred parent zeolite Y may be in the hydrogen, sodium, or ammonium cation form. Preferably step (i) is performed starting from a parent zeolite-Y in the protonic cation form, being the one obtained directly after the preferred mild steaming. Starting from a parent zeolite Y in the ammonium form is less attractive as this may result in the formation of gaseous ammonia in step (ii).

[0060] The parent zeolite Y used in step (i) is thus in any event not a USY zeolite. The zeolite as obtained by the process may however be referred to as an ultra-stable zeolite-Y or USY because of its increased hydrothermal stability, in turn due to its reduced unit cell size after step (iv).

[0061] The zeolite-Y as used as parent zeolite-Y and the Y and USY zeolites obtained in steps (i)-(v) suitably do not contain an organic protecting agent. It is found that the process may be performed in the absence of such chemically bonded protective agents, such as tetraalkylammonium cations. Chemically bonded protective agents may be present, but applicants found that the same or even better advantageous products may be obtained when such agents are not present. The carboxylate containing salts are not regarded as chemically bonded protective agents. The carboxylate containing salts are not undesired as protective agents as carboxylate ions do not bind to the zeolite, can be washed of, do not need to be removed by calcination, are low cost, and pose relatively few complications to the resulting waste water.

[0062] Step (i) may be performed by the method described in applicants US2022073359. In step (i) the parent zeolite Y is contacted with an aqueous solution comprising a carboxylate salt, of which at least 40 mol% and at most 80 mol% of the cations are protons and wherein the pH is in the range of 1 to 5 to obtain an intermediate acid-treated zeolite Y. Preferably at least 45 mol% and at most 75 mol% and more preferably, at least 50 mol% and at most 70 mol% of the cations are protons. When the percentage of protons is higher than 80 mol%, the obtained zeolite will feature less intrinsic zeolitic properties, such as crystallinity and acidity. On the other hand, when the percentage is lower than 40 mol%, no mesopore formation takes place. The anion of the carboxylate salt is preferably an anion of one or more of the following acids: oxalic acid, malic acid, lactic acid, tartaric acid, citric acid, acetic acid, benzoic acid, formic acid, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, monosodium citrate, disodium citrate, or any combination hereof. Examples of preferred carboxylate salts are monosodium citrate (NaH2Citrate), having 67 mol% of cations protonic, mono sodium malate (NaHmalate), having 50 mol% of cations protonic, mono sodium ethylenediaminetetraacetic acid (NaHsEDTA), having 75 mol% of cations protonic, mono sodium tartrate (NaHtartrate), having 50 mol% of cations protonic, Nao 5Ho.5acetate, having 50 mol% protonic, and Nag 5H0 slactate having 50 mol% protonic.

[0063] The cation of the carboxylate salt in step (i) is suitably an alkali metal cation, a water-soluble alkaline earth metal cation or an ammonium cation and combinations thereof. Examples of suitable cations are sodium, potassium and ammonium.

[0064] Also mixtures of carboxylate salts can be used, which does not affect the percentage of protons in the individual salts, and an average percentage of cation protons may be derived by calculating the stoichiometric amounts. In the case the carboxylate salt is mixed with a salt devoid of protons or hydroxyls, such as NaCI or KNO3, no effect on the percentage of protonic cations is taken into account. However, when the carboxylate salt is mixed with an alkali hydroxide, it is assumed that the hydroxyl ion [-OH] combines with the proton [H+] of the salt, is neutralized into water, and the alkali cation takes the place of the proton. For example, when one equivalent of monosodium citrate (NaH2Citrate, 67% protonic) is mixed with one equivalent of NaOH, the resulting carboxylate would be disodium citrate (Na2Hcitrate, 33% protonic) and therefore no longer relevant for the invention. Similarly, if a non-carboxylate acid is mixed with the carboxylate salt, the protons are counted as preferred cations of the carboxylate salt. For example, if one equivalent of disodium malate (Na2malate, 0% protonic) is mixed with one equivalent of HCI, a carboxylate salt of mono sodium malate (NaHmalate, 50% protonic) is obtained, in combination with one equivalent of NaCI.

[0065] The concentration of the carboxylate salt in solution may be between 0.01 and 5.0 M. The pH of the reaction medium in step (i) are preferably in the range of 1 to 5, and more preferably in the range of 2 to 4. The reaction medium being the zeolite and the aqueous phase which is in contact with the zeolite. The aqueous phase which is in contact with the zeolite is referred to as the reaction solution. Temperature at which step (i) is performed may vary between ambient temperature to 100°C. The pressure at which step (i) is performed may vary from ambient pressure to 10 bar, and is preferably ambient pressure. Herein, step (i) commences the first moment part of the aqueous solution comprising a carboxylate salt is copresent with part of the total amount of the zeolite Y in the reaction medium.

[0066] The contacting with the carboxylate salt and the parent zeolite Y can be performed in a conventional direct contacting method, wherein the parent zeolite Y, optionally present as part of an aqueous slurry, is directly, that is, in one go, contacted with the aqueous solution comprising a carboxylate salt. Yet, another suitable method to contact the carboxylate salt with the parent zeolite is to add the zeolite powder and the carboxylate salt powder into a stirred tank with the required water at room-temperature, followed by heating the suspension towards the desired temperature and letting react for the desired time. Preferably step (i) is performed in a gradual contacting in a time period of between 15 seconds and 300 minutes, wherein the aqueous solution comprising a carboxylate salt is added to the parent zeolite Y at a rate of below 3 mmol carboxylate salt per gram of parent zeolite Y per minute and wherein between 0.1 and 10 mmol of carboxylate salt is added in total per gram of parent zeolite Y. Such a gradual contacting is especially advantageous when step (i) is performed at a larger scale. Preferably the gradual contacting of step (i) is performed in a time period of between 2 and 60 min, and more preferably between 5 and 30 min. The gradual contacting may be by continuous or intermittently adding the aqueous solution comprising a carboxylate salt to the parent zeolite Y. Salt addition rates can be expressed as mol of salt added per gram of parent zeolite per minute, and are preferably below below 2 mmol g_1 min_1 , and most preferably below 1 mmol g_1 min_1 . The solid-to-liquid ratio can be between 1 and 300 g parent zeolite Y per liter of aqueous solution comprising a carboxylate salt. Effective ranges of carboxylate salt (in mmol) to parent zeolite Y (in g) ratios are 0.1 to 10 mmol per gram, preferably 1 to 6 mmol per gram.

[0067] The intermediate acid-treated zeolite Y as obtained in step (i) can be suitably separated from the suspension by known separation processes such as filtration and / or by using centrifugal forces. Step (i) is finished when the intermediate acid- treated zeolite Y is separated from at least 80% the reaction solution, using for example filtration or centrifugation steps. Preferably the acid-treated zeolite Y is separated from the suspension using a plate filter resulting in a cake of acid-treated zeolite Y. During step (i) the SAR of the material typically increases from a value between about 4 to 8 to a value between about 7 to 11 mol / mol.

[0068] In step (ii), the acid-treated intermediate zeolite Y from step (i) is contacted with a solid base or a base solution to obtain an intermediate acid-alkaline-treated zeolite Y. Step (ii) may be performed by known base treatments suited for mesoporisation as for example described in applicants US2022073359, WO201 7 / 148852 and WO2019 / 025428. Step (ii) can be performed in a conventional direct contacting method, wherein the intermediate acid-treated zeolite Y, optionally present as part of an aqueous slurry, is directly, that is, in one go, contacted with the solid base or with the base solution. In Step (ii) the intermediate acid-treated zeolite Y may also be gradually contacted with a solid base or a base solution to obtain an intermediate acid-alkaline-treated zeolite Y. The intermediate acid-treated zeolite Y may be present on a membrane as in Figure 2 of US20211711356 and more preferably as the cake of acid-treated zeolite Y as present in a plate filter as obtained in step (i) as described above. A base solution will then flow through the layer or cake, also referred to a fixed bed configuration, of intermediate acid-treated zeolite Y. This preferred manner of performing step (ii) is advantageous because the intermediate acid-alkaline-treated zeolite is already substantially separated from the base solution when step (ii) is finished. During step (ii) the SAR of the material typically decreases from a value between about 7 to 11 mol / mol, to a value between about 5 to 8 mol / mol.

[0069] Step (ii) may alternatively be performed by gradually adding the solid base or a base solution added to an aqueous suspension comprising the intermediate acid- treated zeolite Y to obtain intermediate acid-alkaline-treated zeolite Y. Herein, gradual addition of base with a zeolite is different compared to the state of the art contacting. Typically, in the state of the art, a total amount of base is contacted with a total amount of zeolite directly, that is, in one go, over a period smaller than one minute, typically by adding the zeolite powder, in one go, to a prepared alkaline solution. As such, the maximum amount of base contacted with the total amount of zeolite over a period of one minute is 100% of the total amount of base. Herein, in step (ii), the total amount of base is gradually or stepwise contacted with the total amount of zeolite over a longer time period, preferably at least 2 minutes, more preferably at least 5 minutes, and most preferably at least 10 min, such that the maximum amount of base added to the zeolite over a period of one minute in the time period is preferably at most 50%, more preferably at most 20%, and most preferably at most 10% of the total amount of base added to the zeolite in step (ii).

[0070] The gradual contacting of the base solution may be performed in a time period of between 15 seconds and 60 minutes, preferably between 2 and 45 minutes, and most preferably between 5 and 30 minutes, wherein the addition may be continuous or intermittently. Base addition rates can be expressed as mol of base added per gram of intermediate acid-treated zeolite Y per minute, and are preferably below 5 mmol g_1 min_more preferably below 3 mmol g_1 min_and most preferably below 1.5 mmol g_1 min_The ratio between the intermediate acid-treated zeolite Y and the total liquid volume at the end of step (ii) can be between 1 and 300 g the intermediate acid-treated zeolite Y per liter. This is also referred to as the solid-to- liquid ratio (SLR). Effective ranges of base (in mmol) to intermediate acid-treated zeolite Y (in g) ratios are 0.1 to 15 mmol per gram, preferably 2 to 8 mmol per gram of intermediate acid-treated zeolite Y.

[0071] The solid base or the base solution in step (ii) is suitably an inorganic base. The inorganic base is suitably LiOH, NaOH, KOH, CsOH, and / or NH4OH, and preferably KOH or NaOH, and more preferably NaOH. The base solution may thus be an aqueous solution comprising the following bases LiOH, NaOH, KOH, CsOH or NH4OH and combinations hereof. The concentration may be between 0.01 and 5.0 M. The pH of the reaction medium in step (ii) may vary between 9 and 13.5, more preferably in the range of 10 to 13, and most preferably in the range of between 11 and 12.5. The reaction medium being the zeolite and the aqueous phase which is in contact with the zeolite, including the fraction of solid base or base solution already brought in contact with the zeolite while performing step (ii). The aqueous phase in contact with the zeolites is referred to as the reaction solution. Temperature at which step (ii) is performed may vary between ambient temperature to 100°C. The pressure at which step (ii) is performed may vary from ambient pressure to 10 bar, and is preferably ambient pressure. The contacting of the solid base, being anhydrous or hydrated bases such as NaOH, KOH, LiOH, and CsOH in the solid state, with the zeolite can be achieved preferably by adding the solid base to the reaction medium which is in contact with the zeolite. Herein, step (ii) commences the first moment part of the total amount of the alkaline solution or solid base is copresent with part of the total amount of zeolite in the reaction medium.

[0072] The intermediate acid-alkaline-treated zeolite Y as obtained in step (ii) can be suitably separated from the suspension by known separation processes such as filtration and / or by using centrifugal forces. Step (ii) is finished when the intermediate acid-alkaline-treated zeolite Y is separated from at least 80% of the reaction solution, using for example filtration or centrifugation steps. In a more preferred embodiment the starting acid-treated zeolite Y is present as a cake in a plate filter when performing step (ii). This results in that the intermediate acid-alkaline-treated zeolite Y as obtained in step (ii) will also be present as a cake in the plate filter.

[0073] After step (ii) and before step (iii) an additional acid contacting step (iia) is performed. In step (iia) aluminum is removed from the intermediate acid-alkaline- treated zeolite Y and no or some mesoporisation takes place. Preferably the SiO2 / Al2O3 ratio (SAR) of between 5 and 8 mol / mol of the intermediate acid- alkaline-treated zeolite Y is increased to a value of between 5 and 10 mol / mol in step (iia). This is advantageous because now less aluminum has to be removed in steam treatment step (iv) and acid step (v) which makes the overall process more energy efficient. In step (iia) the obtained intermediate acid-alkaline-treated zeolite Y of step (ii) is subjected to an additional acid treatment step (iia) before performing step (iii) to obtain an intermediate acid-alkaline-acid-treated zeolite Y. The obtained intermediate acid-alkaline-acid-treated zeolite Y is subjected to step (iii) in this embodiment of the invented process. This acid contacting step (iia) is therefore suitably performed by contacting the intermediate acid-alkaline-treated zeolite Y of step (ii) with an aqueous solution comprising a carboxylate salt, of which at least 40 mol% and at most 80 mol% of the cations are protons, and wherein the pH is in the range of 1 to 5 to obtain an intermediate acid-alkaline-acid-treated zeolite Y. The further preferred conditions of step (iia) are preferably those of step (i) as described above with the exception that the amount of carboxylate salt per gram of intermediate acid-alkaline-treated zeolite Y is about 20-50% lower.

[0074] The contacting in step (iia) may be performed in a suspension of the intermediate acid-alkaline-treated zeolite Y and the aqueous solution comprising a carboxylate salt. Preferably the starting intermediate acid-alkaline-treated zeolite Y is present as a cake in a plate filter when performing step (iia). This results in that the intermediate acid-alkaline-acid-treated zeolite Y as obtained in step (iia) will also be present as a cake in the plate filter.

[0075] In one embodiment, in step (i) and / or step (ii) and / or step (iia) an inorganic salt is preferably present having cations chosen from sodium and / or potassium and anions chosen from chloride, nitrate and / or sulfate. The concentration of inorganic salts is suitably 2 to 5 times higher than the concentration of carboxylate salt or base applied in steps (i) and (iia) and (ii) respectively, and is at least 1 mmol per gram, preferably at least 3 mmol per gram, and most preferably at least 5 mmol per gram of the treated zeolite. Ammonium salt such as ammonium nitrate or ammonium chloride, such as described in US2004141911 , may also be present in step (i). A problem of using ammonium salts in step (i) is that the resulting intermediate acid- treated zeolite Y will be in the ammonium form. When this intermediate acid-treated zeolite Y in the ammonium form is treated in step (ii), to yield the intermediate acid- alkaline-treated zeolite, undesired release of gaseous ammonia will occur. This represents a safety and environmental complication. Hence this inhibits the industrial use of ammonium salts in step i). Obviously, similar complications occur if ammonium salts would be used in step (ii).

[0076] Potassium salts are especially preferred for step (i) when step (ii) is performed with the corresponding base, e.g. the application of KCI in step i) when the base step (ii) is executed in KOH. The obtained acid-alkaline-treated material will then be mostly in the potassium form, which is found beneficial for reducing the sodium content in the subsequent ammonium ion exchange in step (iii).

[0077] The use of the inorganic salt in the preparation of mesoporous USY zeolites in this process is surprising as the effect on the preservation of the intrinsic zeolitic properties only becomes clear after application of steps iv) and v).

[0078] Applicants found that sodium and potassium salts display further surprising benefits as compared to the use of ammonium salts. The application of ammonium salts has been found to reduce the mesopore forming efficiency of step (i). When ammonium salts are present in step (i), more carboxylate salt is needed to ensure a suitable degree of mesopore formation. Conversely, when potassium or sodium salts are present, less carboxylate salt is needed to achieve a suitable degree of mesopore formation. This shows that, in contrast to ammonium salts, sodium and potassium salts enable to use less carboxylate salts, being preferred from a cost and ecological perspective. Also in step (ii) the presence of potassium and sodium salts results in a higher mesopore formation per unit of alkaline used. The use of less acid in step (i) or less alkaline during step (ii) is advantageous from cost perspective and also as the resulting zeolite-containing reactive media will display less extreme pH values, which makes the mesoporisation process easier to control.

[0079] In the reaction solution of steps (i), (ii) and (iia) dissolved aluminum and silicon are present and when the acid-treated zeolite, and / or acid-alkaline treated zeolite and / or acid-alkaline-acid-treated zeolite Y are separated from the majority of the reaction solution some of this aluminum and silicon may remain on the zeolite. It is therefore preferred to wash the obtained zeolites to remove this aluminum and silicon. After performing step (i), and / or after step (ii) and / or after performing step (iia) it is preferred to wash the acid-treated zeolite, and / or acid-alkaline treated zeolite and / or acid-alkaline-acid-treated zeolite Y with an aluminum-free and silicon- free aqueous solution of pH 6-9. Preferably the washing is performed after at least 80 wt% of the reaction solution is separated from the obtained zeolite. Washing is preferably performed by contacting an aqueous washing solution with the zeolite. More preferably a stream of the aqueous washing solution flows through a cake of zeolite covering a sheet or cloth of filtration media, such as on a Buchner filter or on a plate filter. Preferably the aqueous washing solution is substantially Al and Si-free solution, wherein the washing solution does not contain more than 0.1 g / L of silicon and aluminum combined. The aqueous washing solution may be distilled water. Preferably washing aqueous solutions comprising sodium and potassium salts are used, with concentration of at least 0.1 mmol / g, preferably at least 1 mmol of salt per gram of to be washed zeolite. The increased conductivity of these solutions enables to evacuate the Si and Al species more effectively, which is assumed to be due to the higher ion strength of the solution. Accordingly, less washing volume can be used to attain a fixed level of Si and Al salts in the washing water. Washing with sodium and / or potassium salts could result in that residual sodium or potassium ions left in the zeolite. Unlike in the state of the art, this is however not a problem as these cations will be removed from the zeolite in step (iii).

[0080] The washing of the zeolite after the treatments of step (i), step (ii) and / or step (iia), preferably takes place until the washing aqueous solution obtained after the washing contains less than 5 g / L, preferably less than 3 g / L, and more preferably less than 1 g / L of silicon and aluminum combined. The quantity of Si and Al in the washing water is measured by inductively coupled plasma optical emission spectrometry (ICP-OES). By performing this washing step, the obtained mesoporous zeolite Y is not diluted by residual species of silicon or aluminum. Accordingly, the resulting materials by this process feature improved intrinsic properties, such as crystallinity, microporosity, and acidity, such as B530.

[0081] In a preferred process the contacting in step (i) is performed in a suspension of the parent zeolite Y and the aqueous solution, wherein the acid-treated zeolite Y is separated from the suspension using a plate filter resulting in a cake of the acid-treated zeolite Y, wherein in step (ii) is performed starting with the acid-treated zeolite Y as present as the cake in the plate filter resulting in a cake of the intermediate acid- alkaline-treated zeolite Y in the plate filter, wherein step (iia) is performed is performed starting with the acid-alkaline treated zeolite Y as present as the cake in the plate filter resulting in a cake of the intermediate acid-alkaline-acid-treated zeolite Y in the plate filter, and wherein the cake obtained in step (i), (ii) and (iia) is washed before performing the next step and wherein between performing step (i) and (ii) and between step (ii) and (iia) no drying of the cake takes place. The washing is preferably as described above.

[0082] Between steps (i)-(iii) the obtained solids are preferably washed and preferably not dried. Washing is suitably performed with an aqueous solution comprising sodium and / or potassium. Within the context of this invention, the concomitant ion exchange to sodium or potassium taking place during washing has no negative effect as it occurs prior to the ion exchange of step (iii). In contrast, the concomitant ion exchange during the removal of Si and Al species, can be desired. For example, by washing with sodium or potassium after a step (i) executed in the presence of ammonium, the release of ammonia during the subsequent step (ii) can be avoided. Similarly, the use of potassium salts for the washing is preferred when step (i), step (ii), and / or step (iia) are performed in the excess of potassium cations. The obtained acid-treated, acid-alkaline-treated, and / or acid-alkaline-acid treated T1 material will feature an increased potassium content, which is beneficial for reducing the sodium content in the subsequent ammonium ion exchange in step (iii). An example of a suitable sodium-containing stream for washing is natural water from which the magnesium and calcium have been removed via ion exchange with sodium, also known as ‘soft’ water. This soft water is advantageous as it is more economical to produce as compared to demineralized water. Such soft water may also be used as part of the preferred reaction solutions as used in steps (i), (ii), and (iia).

[0083] Step (iii) is an ion exchange step wherein the zeolite Y in the ammonium form. The ion exchange may be performed by well known methods. In step (iii) the intermediate acid-alkaline-acid treated zeolite Y is contacted with an aqueous solution containing an ammonium salt thereby suitably reducing the combined potassium and sodium content to below 0.5 wt% and obtaining a zeolite Y in the ammonium form. In the ammonium ion exchange step also undesired exchange cations next to sodium and potassium, such as other alkali and alkaline earth metals, will be removed to low contents. This is advantageous because it makes the steaming process more effective in generating mesoporosity and yielding materials of high intrinsic zeolitic properties, such as crystallinity, microporosity, and acidity, such as B350 / AI. Ammonium exchanges are industry standard, and are typically executed in aqueous solutions at temperatures from ambient to 100°C, preferably 60-80°C, using simple inorganic salts such as ammonium sulphate, ammonium nitrate and ammonium chloride. They are typically aimed to replace sodium with ammonium ions. When the zeolite Y which is subjected to such an ammonium exchange step, the preferred combined potassium and sodium content of the resulting zeolite in the ammonium form is below 0.5 wt%, preferably below 0.4 wt%, and most preferably below 0.3 wt%.

[0084] The steam treatment of step (iv) may be performed under conditions known for steam treating of a zeolite as for example described in US2004141911 . Preferably step (iv) is performed at a temperature of between 600 and 850°C for between 30 and 300 minutes by contacting the zeolite Y in the ammonium form obtained in step (iii) with a gas comprising at least 50 vol.% of gaseous water. In step (iv) the bulk SAR of the solid does not change significantly, whereas the amount of framework aluminum strongly reduces. Accordingly, in step (iv) the unit cell size will suitably reduce to a value smaller than 24.45 A, hence turning the Y zeolite into a USY zeolite.

[0085] During steps (iii) and (iv) the SAR remains mostly constant, typically in the range of 5 to 12 mol / mol, preferably in the range of 6.5 to 11 mol / mol, and most preferably in the range of 7 to 10 mol / mol.

[0086] In step (v) the intermediate steam modified USY zeolite obtained in step (iv) is contacted with acid to obtain a steam-acid modified USY zeolite. This step may also be referred to as an acid dealumination. Step (v) may be performed under conditions known for acid dealumination of a zeolite as for example described in the afore mentioned US2004141911 . The acid in step (v) may be an organic acid, such as a carboxylic acid. The acid is suitably a mineral acid, preferably HNO3, HCI, H2SO4, H3BO4, H3PO4, HF and / or NH4F and more preferably HNO3, HCI or H2SO4.

[0087] The non-framework aluminium as formed in step (iv) is removed in step (v) from the bulk thereby increasing the SAR of the zeolite. In step (v) the bulk SAR is increased from a preferred value of between 5 and 10 mol / mol preferably to a value greater than 10 mol / mol, more preferably greater than 20 mol / mol and even more preferably to the SAR ranges described below. Step (v) is preferably performed by gradually contacting the acid with the intermediate steam modified USY zeolite. As in step (i) for the non-steamed parent Y zeolite, the acid treatment of the intermediate steam modified USY zeolite is suitably executed in a gradual contacting in a time period of between 15 seconds and 300 minutes, wherein a solid acid or acid solution is added to the intermediate steam modified USY zeolite at a rate of below 3 mmol acid per gram of intermediate steam modified USY zeolite per minute and wherein between 0.1 and 10 mmol acid is added in total per gram intermediate steam modified treated USY zeolite. The pH during step (v) varies from -2 to 5, preferably between 0 and 4, and preferably between 1 and 3.

[0088] Applicants found that the USY zeolite obtained by this process of the invention has excellent catalytic properties. The below detailed description of the USY zeolite obtainable by this process also apply on the USY zeolite according to this invention. These catalytic properties are the resultant of the below unique combination of material properties. The USY zeolite as obtained by the inventive process is a high SAR zeolite Y, wherein the SiO2 / Al2O3 ratio is greater than 10 mol / mol and preferably greater than 20, more preferably greater than 25 mol / mol, more preferably greater than 30 mol / mol, more preferably greater than 35, more preferably greater than 40, more preferably greater than 45, more preferably greater than 50, most preferably greater than 60 mol / mol, preferably smaller than 500 mol / mol, more preferably smaller than 300 mol / mol, and most preferably smaller than 150 mol / mol. The relating unit cell size is smaller than 24.45 A, preferably smaller than 24.40 A, more preferably smaller than 24.35 A, more preferably smaller than 24.30 A, most preferably smaller than 24.28, preferably greater than 24.20 A, more preferably greater than 24.22 A, most preferably greater than 24.23 A. The zeolite is preferably in the protonic form. The sodium content of the obtained USY zeolite, as expressed as the soda (Na2O) to alumina (AI2O3) molar ratio (NAR), is low, preferably below 0.10 mol / mol, more preferably below 0.06 mol / mol, more preferably below 0.04 mol / mol, more preferably below 0.03 mol / mol, and most preferably below 0.02 mol / mol. This contributes to the desired catalytic properties of the zeolite in hydrocracking. The zeolite USY as obtained by the process may feature, unlike the state of the art, very low soda (Na2O) contents, suitably below 0.3 wt%, preferably below 0.15 wt%, more preferably below 0.1 wt%, and most preferably below 0.05 wt%.

[0089] The zeolite USY as obtainable by the process may have a mesopore volume (Vmeso) greater than 0.30 ml / g, suitably greater than 0.35 ml / g, preferably greater than 0.40 ml / g. more preferably greater than 0.45 ml / g, more preferably greater than 0.50 ml / g, and most preferably above 0.55 ml / g, preferably below 1.00 ml / g, more preferably below 0.80 ml / g, and most preferably below 0.70 or may be below 0.60 ml / g.

[0090] The micropore volume (Vmicro) of the USY zeolite obtained by this process may be greater than 0.22 ml / g, preferably greater than 0.23 ml / g, preferably greater than 0.24 ml / g, more preferably greater than 0.25 ml / g, more preferably greater than 0.26 ml / g, more preferably greater than 0.27 ml / g, most preferably greater than 0.28 ml / g, preferably below 0.35 ml / g, more preferably below 0.33 ml / g.

[0091] The micropore volume measured by argon (Vmicro-Ar) relating to the porosity of the crystalline phase of the USY zeolite obtained by this process is suitably above 150 and suitably below 250 ml / g, preferably greater than 165 ml / g, more preferably above 175 ml / g, and preferably above 180 ml / g, preferably below 215 ml / g, and more preferably below 200 ml / g.

[0092] The zeolite USY as obtainable by the process may have a total surface area greater than 600 m2 / g, preferably greater than 700 m2 / g, more preferably greater than 750 m2 / g, more preferably greater than 800 m2 / g, most preferably greater than 850 m2 / g, preferably smaller than 1200 m2 / g, and more preferably smaller than 1100 m2 / g.

[0093] The relative crystallinity of the zeolite USY as obtainable by the process may be at least 25 % relative to a NaY preferably at least 30 %, more preferably at least 35 %, more preferably at least 40 %, most preferably at least 45 %, preferably below 75 %, and more preferably below 70%.

[0094] The B350 / AI of the USY zeolite as may be obtained by the process is between 0.1 and 0.2 mol / mol, preferably greater than 0.11 mol / mol, more preferably greater than 0.12, preferably below 0.20 mol / mol, and more preferably below 0.18 mol / mol. This value is comparable to commercially available non-mesoporous zeolites USY such as CBV720, CBV760, and CBV780 as obtainable from Zeolyst International. This shows that the acid strength is sufficient for the USY zeolite to be used as part of a hydrocracking catalyst.

[0095] Applicants found that the zeolite Y materials obtained after the ion exchange Step (iii), that is, before the steaming step (iv), feature unique properties. Is believed that these unique properties result from the choice of the parent Y zeolite and how steps (i), (ii), (iia) and (iii) are performed. The invention is therefore also directed to a first intermediate Y zeolite having a micropore volume greater than 0.28 ml / g and a mesopore volume greater than 0.15 ml / g, a SiO2 / Al2O3 ratio of 5 to 12 mol / mol, a unit cell size between 24.45 A and 24.55 A, a total surface area greater than 700 m^ / g, a NAR below 0.15, and a relative crystallinity of at least 75% relative to a NaY.

[0096] The SiO2 / Al2O3 ratio is preferably greater than 6 mol / mol, more preferably greater than 7 mol / mol, most preferably greater than 7.5 mol / mol and preferably smaller than 11 , more preferably smaller than 10, more preferably smaller than 9.5 mol / mol, and most preferably smaller than 9 mol / mol. The unit cell size is preferably smaller than 24.60 A, more preferably smaller than 24.57 A, more preferably smaller than 24.54 A, most preferably smaller than 24.52 A, preferably greater than 24.45 A, and more preferably greater than 24.48 A. The intermediate Y zeolite is preferably in the ammonium or protonic form, more preferably in the ammonium form. The sodium content of the first intermediate Y zeolite, as expressed as the soda (Na2O) is below 1 .0 wt%, preferably below 0.8 wt%, more preferably below 0.6 %, and more preferably below 0.4%. The NAR is typically below 0.15 mol / mol, suitably below 0.10 mol / mol, preferably below 0.08 mol / mol, more preferably below 0.06 mol / mol, and most preferably below 0.05 mol / mol.

[0097] The first intermediate Y zeolite may have a mesopore volume (Vmeso) greater than 0.15 ml / g, preferably greater than 0.20 ml / g, more preferably greater than 0.25 ml / g, more preferably greater than 0.25 ml / g, most preferably greater than 0.30 ml / g, suitably below 0.60 ml / g, preferably below 0.50 ml / g, and more preferably below 0.45 ml / g.

[0098] The micropore volume (Vmicro) of the first intermediate Y zeolite may be greater than 0.22 ml / g, preferably greater than 0.25 ml / g, and preferably greater than 0.26 ml / g, preferably greater than 0.27 ml / g, more preferably greater than 0.28 ml / g, more preferably greater than 0.29 ml / g, most preferably greater than 0.30 ml / g, smaller than 0.40 ml / g, preferably smaller than 0.37 ml / g, and most preferably smaller than 0.34 ml / g.

[0099] The first intermediate Y zeolite has a total surface area greater than 700 m2 / g, preferably greater than 750 m2 / g, more preferably greater than 800, most preferably greater than 850 m2 / g, preferably below 1200 m2 / g, and more preferably below 1100 m2 / g.

[0100] The relative crystallinity of the first intermediate Y zeolite may be at least 50 % relative to a NaY preferably at least 60%, more preferably at least 70%, most preferably at least 75%, typically below 120%, and more typically below 100%.

[0101] Applicants found that the low-SAR USY materials obtained after the steaming step (iv), that is, before the final dealumination step (v), feature unique properties. Steaming in prior art processes applied to low-SAR mesoporous faujasites as for example described in Catal. Sci. Technol., 2013, 3, 972-981 result in severe amorphization of the obtained USY zeolite and reduction of Vmeso. In the present process such severe amorphization does not take place resulting in an intermediate USY zeolite having a unique combination of properties, such as an increased Vmeso. The invention is therefore also directed to a second intermediate USY zeolite having a micropore volume greater than 0.18 ml / g and a mesopore volume greater than 0.30 ml / g, a SiO2 / Al2O3 ratio of 5 to 10 mol / mol, a unit cell size smaller than 24.45 A, a total surface area greater than 500 m2 / g, and a relative crystallinity of at least 35 % relative to a NaY.

[0102] The second intermediate USY zeolite preferably has a SiO2 / Al2O3 ratio greater than 6 mol / mol, more preferably greater than 7 mol / mol, most preferably greater than 7.5 mol / mol and preferably smaller than 10, preferably smaller than 9.5 mol / mol, and most preferably smaller than 9 mol / mol. The unit cell size is preferably smaller than 24.40 A, more preferably smaller than 24.35 A, even more preferably smaller than 24.32 A, most preferably smaller than 24.30 A, preferably greater than 24.20 A, and more preferably greater than 24.25 A. The second intermediate USY is preferably in the protonic form. The sodium content of the second intermediate USY zeolite, as expressed as the soda (Na2O) is below 1 .0 wt%, preferably below 0.8 wt%, more preferably below 0.6 %, and more preferably below 0.4%. The NAR is typically below 0.15 mol / mol, suitably below 0.10 mol / mol, preferably below 0.08 mol / mol, more preferably below 0.06 mol / mol, and most preferably below 0.05 mol / mol. The second intermediate USY zeolite has a mesopore volume (Vmeso) greater than 0.30 ml / g, suitably greater than 0.35 ml / g, preferably greater than 0.40 ml / g, preferably greater than 0.50 ml / g, suitably below 0.80 ml / g, preferably below 0.60 ml / g, and more preferably below 0.55 ml / g.

[0103] The second intermediate USY zeolite has a micropore volume (Vmicro) greater than 0.17 ml / g and lower than 0.28 ml / g. The Vmicro is preferably at least 0.18 ml / g, more preferably at least 0.19 ml / g, more preferably at least 0.20 ml / g, most preferably at least 0.21 ml / g, typically below 0.26 ml / g, and more typically below 0.25 ml / g.

[0104] The second intermediate USY zeolite has a total surface area greater than 500 m^ / g, preferably greater than 550 m^ / g, more preferably greater than 600 m^ / g, most preferably greater than 650 m^ / g, preferably below 900 m^ / g, and more preferably below 800 m2 / g.

[0105] The relative crystallinity of the zeolite USY as obtainable by the process may be at least 25 % relative to a NaY as measured via ASTM 3906, preferably greater than 30%, more preferably greater than 35%, most preferably greater than 40%. A higher relative crystallinity is preferred but it is found that typically the relative crystallinity remains below 75%, and more even below 60% relative to NaY.

[0106] In view of the favorable catalytic activity especially in its selectivity to middle distillates the invention is also directed to the use of the USY zeolite according to this invention or obtained by the processes of this invention as part of a hydrocracking catalyst composition.

[0107] The application of a USY zeolite in a hydrocracking catalyst and in a hydrocracking process is well known. The zeolite USY as prepared by this process can be advantageously used in such known hydrocracking compositions and provide improved yields to middle distillates and activity when applied in a hydrocracking process. Such a hydrocracking catalyst suitably comprises the USY zeolite according to this invention or obtainable by the process of this invention, an old- ILIPAC Group VIII metal and a binder. The Group VIII metal is suitably platinum, palladium, nickel or cobalt.

[0108] The binder preferably comprises, and preferably even consists of, one or more non-zeolitic inorganic oxides. Preferably, the non-zeolitic inorganic oxide(s) make up more than 90 wt. of the binder, more preferably more than 95 wt. of the binder. Exemplary non-zeolitic inorganic oxides are alumina, silica, silica-alumina, zirconia, clays, aluminium phosphate, magnesia, titania, silica-zirconia and silica- boria. Preferably, the binder comprises a component selected from the group consisting of silica, alumina and amorphous silica-alumina.

[0109] Typically, the content of binder is between 50 to 95 wt% on the total of binder and USY zeolite.

[0110] When the Group VIII metal is palladium and / or platinum the total amount of platinum and / or palladium present in the catalyst is suitably in the range of from 100 ppm to 5.0 percent by weight calculated as element based on total weight of the catalyst, more suitably in the range of from 0.1 to 2.0 percent by weight. If both present, the weight ratio of platinum to palladium (calculated as element) may vary within wide limits, but suitably is in the range of from 0.05 to 10, more suitably 0.1 to 5. In one preferred embodiment of the present invention the catalyst comprises platinum as the sole catalytically active metal, whilst in another preferred embodiment of the present invention the catalyst comprises a combination of platinum and palladium. Platinum and palladium may be present as element, as oxide and / or as sulphide.

[0111] Preferably the hydrocracking catalyst comprises a non-noble Group VIII metal and a group VIB metal. The non-noble Group VIII metal is suitably nickel or cobalt. The group VIB metal is suitably molybdenum or tungsten. Examples of suitable combinations are nickel-tungsten, nickel-molybdenum and cobalt-molybdenum. The content of non-noble group VIII metals oxide is preferably between 0.1 and 20 wt%, more preferably between 1 and 10 wt%, most preferably between 2 and 8 wt%. The content of group VIB metal oxide is preferably between 0,1 and 40 wt%, more preferably between 1 and 35 wt%, most preferably between 10 and 30 wt%. The binder may be silica, silica-alumina or alumina. Examples of hydrocracking catalyst compositions for USY zeolite containing catalysts are described in US20110100875, WO201 1069150, WO2022162680, WO2021185721 . The hydrocracking catalysts described in these publications may be advantageously prepared using the USY zeolite according to the invention. The content of the USY zeolite in the catalyst is preferably between 5 and 50 wt%, preferably between 5 and 35 wt%.

[0112] The catalyst may be pre-sulphided hydrocracking catalyst.

[0113] The invention is also directed to a process to prepare middle distillates by contacting a hydrocarbonaceous feedstock boiling for more than 90 wt% above 350°C under hydrocracking conditions with a hydrocracking catalyst of this invention. Hydrocracking of various feedstocks is a well-known refinery unit operation to prepare middle distillates, such as kerosene and gas oil from petroleum derived feedstocks.

[0114] Hydrocarbonaceous feedstocks refers to a mixture composed mostly of hydrocarbon compounds. Hydrocarbonaceous feedstock may include, crude oil, atmospheric residues, atmospheric distillates, vacuum distillates for example vacuum gas oil (VGO), Light Cycle Oil (LCO) obtained from catalytic cracking unit, a feed obtained after extraction of aromatics from base oil or lubricating oil, a feed obtained after solvent dewaxing of base oil or lubricating oil, thermally cracked oil, coal-derived distillates, light or heavy coker gas oil, deasphalted oil, demetallized oil, animal oil and fat, triglycerides, carboxylic acids, carboxylic esters, fatty acid alkyl esters, Fischer-Tropsch derived stream, pyrolysis oil of plastic waste and / or biomass, vegetable oil, used cooking oil, and any combination thereof. All of the above-mentioned feedstocks may optionally contain metals, and / or nitrogen, and / or oxygen and / or sulphur. The list hereinabove is non-exhaustive. Hydrocracking basically involves catalytically converting hydrocarbon molecules into smaller hydrocarbon molecules in the presence of hydrogen. The hydrocracking catalyst is suitably present as part of a fixed bed of catalyst in a hydrocracking reactor. Hydrocracking conditions usually comprise temperatures in the range of from 250 to 500 °C, hydrogen partial pressures in the range of from 1 to 300 bar, weight hourly space velocities of from 0.1 to 10 kg feed per litre of catalyst per hour and gas / feed ratios of from 100 to 5000 Nl of gas per kg of feed.

[0115] The catalyst is preferably used to convert hydrocarbonaceous feedstocks boiling substantially above 360 C and preferably boiling for 90 wt% above 360 C. The catalyst may be used in a base oil hydrocracker which main products are base oil fractions and which process operates at a feed conversion of below 50 wt percent% and more typically between 20 and 40 wt% percent. Preferably the hydrocracking catalyst is used in a fuels hydrocracker process which main products are preferably naphtha, kerosene and gas oil and wherein the feed conversion is above 40 wt%. The conversion is expressed in the weight percentage of the fraction in the feed which boils above 360 degrees centigrade which are converted to products boiling below 360 degrees centigrade.

[0116] Preferably the fuels hydrocracker is operated in two steps, consisting of a preliminary hydrotreating step followed by a hydrocracking step. In the hydrotreating step nitrogen and sulphur are removed and aromatics are saturated to naphthenes. In the hydrocracking step the heavier fraction of the feedstock boiling at a temperature higher than 360°C is cracked to lower boiling range products such as gas, naphtha, kerosene and diesel.

[0117] The invention is relevant for hydrocracking in the absence of the products from the hydrotreating step, being ammonia and H2S, referred to as ‘sweet mode’. Yet also in the presence of these species, referred to as ‘sour mode’, the benefits, that is, the increased yield of middle distillates, can be achieved.

[0118] Brief description of the Figures:

[0119] Figure 1 shows the classical configuration used to analyze the acidity of faujasites with pyridine adsorbed using in situ infrared spectroscopy.

[0120] Figure 2 shows a flowsheet of one of the preferred embodiments of the process according to this invention.

[0121] Figure 3 shows a graphical representation of the Vmicro and Vmeso of USY zeolites obtained by prior art processes and by the process of this invention. For specific inventive and comparative materials, the associated SAR is mentioned at each data point.

[0122] Figure 4 shows the Vmeso of the USY zeolites obtained in the final acid treatment against the solid yield of the final acid treatment.

[0123] Figure 5 shows the amount of aluminum removed in the final acid treatment against the solid yield of the final acid treatment.

[0124] Figure 6 shows the micropore volumes of mesoporous USY zeolites prepared in comparative experiments A, B, C, D, F, G, H, I, N, 0, P using state of the art technology (triangles) or according to the invention in Example 12 (circle).

[0125] Figure 7 relates the changes in unit cell size (UCS, left side) and molar SAR (right side) to the development of mesopore volume (Vmeso) for state of the art zeolites (P1-P6, empty diamonds, dotted arrows), mesoporous zeolites prepared using state of the art methods by mesoporising high-SAR USYs (D and H, empty triangles, dashed arrows), and mesoporous USY prepared by mesoporising low-SAR Y zeolites using the inventive process involving steps (i, ii, iia, iii, iv, and v) (Examples 16-19, solid circles, solid arrows).

[0126] Figure 8 relates the micropore volumes with the SAR of selected samples.

[0127] Figure 9 relates the relative crystallinity (RC) to NaY with the SAR of selected samples.

[0128] Figure 10 illustrates the micropore volume with the mesopore volume for unsteamed inventive and state of the art samples.

[0129] Figure 11 illustrates the SBET surface area with the mesopore volume for unsteamed inventive and state of the art samples.

[0130] The invention will be illustrated by the following non-limiting examples.

[0131] Example 1

[0132] In this example it will be illustrated how the process of this invention is more energy efficient. Steam treatment is typically performed at elevated temperatures of between 400-800°C. Mesoporisation, like the base treatments, induces loss of material by dissolution. In the prior art processes the heat treatment is typically performed prior to dealumination via acid treatment, and the acid treatment is performed prior to mesoporisation. Applicant has now found that by performing the mesoporisation prior to steaming / dealumination a significantly more efficient use of heat results (Table 1 ).

[0133] For example, in a conventional synthesis, an 80% solid yield of the dealumination step, implies that the total amount of heat per kg of product increases by 25%. Moreover, by executing on such material another step inducing solid losses (e.g. a mesoporisation step with 70% solid yield), the relative energy requirement per kg increases to 179%. Finally, the required calcination step boosts the energy demand with another 100% to 279%, and, in addition, an extra ion exchange step is needed. In contrast, executing the mesoporisation prior the steaming and dealumination yields a similar energy profile as the conventional zeolite, without the need for an extra ion exchange step. Moreover, during the mesoporisation and step (iia), a partial dealumination can be achieved, yielding prior to steaming, instead of a SAR of 5-6, a higher SAR of 8-10, attesting to the removal of 30-50% of the aluminum. This implies that the solid yield during the mesoporisation step may be lower, whereas the solid yield during the dealuminaton after steam treatment step (v) may be higher, as less alumina species need to be removed, which reduces the relative weight-based energy demand from 125% to 118% (Table 1 ). Hence, Table 1 illustrates that the current invention enables to yield mesoporous zeolites using less steps and less energy as compared to the state-of-the-art mesoporous zeolites. Moreover, Table 1 illustrates how the invention enables to reduce the energy demand as compared to conventional non-mesoporous zeolites. Further advantages will be described below when discussing the invention in more detail.

[0134] Table 1

[0135] Steam = 100% yield, Dealumination = 80% yield, mesoporisation = 70% yield, calcination = 100% yield, Mesopor.-syn = 65% yield, dealum.-syn = 85% yield. For sake of simplicity, a similar energy demand for steaming as for calcination was used. *Values in brackets indicate the relative weight-based energy to obtain the product as compared to the product following steam treatment.

[0136] Parent Zeolites

[0137] In the below experiments various parent zeolite-Y were used, provided by Zeolyst International (P1-P6), Tosoh (P7), or Jalon (P8). The properties of these starting parent zeolites are listed in Table 2. Other chemicals were purchased from Fisher Scientific and Sigma-Aldrich and used as received. All below-described wet treatments involve rigorous stirring using magnetic or mechanical stirrers, typically around 250 rpm. Water used for making solutes and washing is standard lab-grade reverse-osmosis (RO) also referred to as demi-water, unless indicated otherwise. Table 2: Parent zeolites. Comparative Experiments

[0138] In the state of the art, synthesis of mesoporous high-SAR USY zeolites involves base treatments on conventional non-mesoporised high-SAR parent zeolites, such as R1 , P2, and P5. Herein such materials have been reproduced, resulting in the materials with properties as in Table 3. Comparative Experiments based on low-SAR parent zeolites are summarized in Tables 4 and 10.

[0139] Table 3: Overview of comparative experiments derived from mesoporisation of high- SAR parent USY zeolites. Table 4: Overview of comparative experiments derived from low-SAR parent Y zeolites.

[0140] Comparative Experiment A

[0141] An aqueous solution containing 40 g of tetrapropylammonium bromide (TPABr) and 2000 mL of water was prepared, placed in a stirred round-bottom flask and heated to 80°C. To this aqueous solution, 100 g of Powder Ref P1 was added, and subsequently an extra 250 mL water was added to the suspension. To this suspension 750 mL of 0.8 M sodium hydroxide (NaOH) aqueous solution was gradually added at a constant rate during 30 min using a peristaltic pump at a temperature of 80°C and at ambient pressure.

[0142] Once the addition was finished, the suspension was immediately filtered on a Buchner, the cake consisting of the intermediate alkaline-treated zeolite-Y was thoroughly washed with water.

[0143] The obtained cake was immediately resuspended in an aqueous solution containing 109 g of (NH4)2SO4 and 1650 mL of water at room temperature. After 1 h the suspension was filtered on a Buchner. This ion exchange procedure was repeated twice. The final cake was washed thoroughly with water, before being dried for 16 h in an oven at 110°C. Finally, the solid was calcined in air for 5 h at 550°C using a ramp of 5°C / min. The properties of the obtained zeolite are described in Table 3.

[0144] Comparative Experiment B

[0145] Comparative Experiment A was repeated except that P2 (CBV760) was used instead of P1 (CBV720), and the concentration of the NaOH aqueous solution was 0.6 M instead of 0.8 M. The properties of the obtained zeolite are described in Table 3.

[0146] Comparative Experiment C

[0147] Comparative Experiment C was prepared following the procedure to prepare material “MZ1” as described on pages 13-14 of WO2021185721 with the addition that an acid treatment was executed prior to the calcination step, as described on page 14 of WO2021185721 for the “MZ2” material. Accordingly, the cake obtained after the filtration step following the base treatment was resuspended in a solution containing 9.2 g of 65% HNO3 and 600 mL of water at 70°C. After 1 h at 70°C, the stirred suspension was filtered and the cake thoroughly washed with water. The obtained zeolite cake was then dried for 16h in an oven at 110°C, finally the solid was calcined in air for 5h at 550°C using a ramp of 5°C / min. The properties of the obtained zeolite are described in Table 3.

[0148] Comparative Experiment D

[0149] Comparative Experiment D was prepared following the procedure for preparing FAU15-AT2-AW described by M. Milina et al. in Catalysis Today, 2014, 235, 176- 183. The properties of the obtained zeolite are described in Table 3.

[0150] Comparative Experiment E

[0151] Comparative Experiment B was repeated except that P5 (CBV780) was used instead of P2 (CBV760). The properties of the obtained zeolite are described in Table 3.

[0152] Comparative Experiments F-L, N, and O

[0153] In Table 5 known materials obtained by the mesoporisation of high-SAR USY materials of different molars SARs are reproduced by exactly repeating experiments of the cited publication for each of the reproduced examples. The properties of the obtained zeolite are described in Table 3.

[0154] Table 5:

[0155] Comparative Experiments N and 0

[0156] Experiments N and 0 were performed by repeating experiment ‘AT-TPA-0.2’ as described in Cryst. Growth Des. 2012, 12, 6, 3123-3132. Applicants have learnt that the calcination of an alkaline-treated and ion-exchanged USY zeolite (Step 6, Table 1 ) in the state of the art leads to severe amorphization of the USY and this increases with the SAR of material. For example, Comparative experiment N yields a material in the sodium form (NAR of 0.62) with a high relative crystallinity of 54% as compared to NaY. Upon ion exchange and calcination (Comparative experiment 0), the NAR goes down to 0.03, but the crystallinity reduces strongly down to 36% relative to NaY.

[0157] Comparative Experiment P

[0158] Experiment E was repeated except in that instead of the ion exchange in ammonium sulphate, the alkaline-treated cake was treated in hydrochloric acid. To do so, the alkane-treated cake was resuspended in 1440 mL of water, after which 480 ml of 0.4 M HCI was added gradually added over the course of one 1 h using a dosing pomp. Filtration and drying was executed similar as for the ion exchange.

[0159] Limitations of mesoporous high-SAR materials prepared in the state of the art

[0160] The data in Table 3 enable a number of conclusions to be drawn:

[0161] • A variety of mesopore volumes can be achieved by the state of the art processes, yet the micropore volumes never exceed 0.25 ml / g (See also Figure 3).

[0162] • The upper limit of the micropore volumes reduces strongly with SARs increasing over 30 mol / mol for the state of the art mesoporous USY zeolites (See also Figure 6). • The relative acid strength (B350 / AI) strongly reduces as compared to the parent zeolites, and never exceeds 0.09.

[0163] • Samples with the highest intrinsic zeolitic properties, such as micropore volume, crystallinity, and acidity, are made using organic additives in the base treatment, such as TPABr or CTACI, wherein TPABr seems to perform better than CTACI.

[0164] • The mesoporous USY samples strongly amorphize upon removal of sodium via ion exchange and calcination.

[0165] • The NAR is typically around 0.05 mol / mol, being much higher than in the parent zeolites, which display NARs of 0.00 mol / mol.

[0166] Inventive Examples

[0167] Inventive examples illustrate the nature of the invention. Obtained properties of the resulting solids are summarized in Tables 6, 8, 9, and 10.

[0168] Table 6: Overview of high SAR mesoporous USY zeolites. Examples derived from P4, after steaming and final acid treatment according to the process of this invention and illustrated by Figure 2.

[0169] Na=not ana ysed

[0170] Example 2

[0171] Example 2 was made by an acid-base-acid sequence followed by ion exchange, steam and acid treatment. This was achieved by, in step (i), introducing 25 g of P4 (CBV400) in 250 ml of 0.15 M monosodium citrate in demi water, let it react at 95°C for 1 h, followed by filtration and washing using a Buchner filter. In step (ii), the obtained acid-treated zeolite cake was resuspended 160 ml of demi water, heated to 65°C, and treated in base by the gradual drop-wise introduction of 63 ml of a 2.4 M NaOH solution over the course of 30 min, followed by 15 min of stirring at the same temperature, followed by separation and washing as mentioned above. In step (iia), the obtained acid-base-treated zeolite cake was subsequently resuspended in 225 ml of 0.05 M monosodium citrate in demi water, reacted at 65°C for 1 h, followed by separation and washing as mentioned above. Next, in step (iii), the obtained acid- base-acid-treated zeolite was ion exchanged to the ammonium form by resuspending the obtained zeolite cake in 225 ml of 0.5 M ammonium sulphate in demi water, reacted at 80°C for 1 h, followed by separation and washing as mentioned above, repeating this procedure twice, followed by drying overnight in air at 110°C. Finally, the zeolite powder was steamed (step (iv)), and acid treated (step (v)). Hereto, 2.5 g of the obtained material was steamed in a tubular oven at 700°C for 2.5 h (ramp rate 25°C / min), in an atmosphere of 100% steam created by introducing 30 ml / h of distilled water into one side of the oven. 1 .5 g of the hereby obtained material was subsequently treated in 40 ml of 0.3 M H2SO4, reacted at 65°C for 1 h, followed by separation and drying as mentioned above.

[0172] The properties of the obtained zeolite are described in Table 6. This experiment yielded a mesoporous material of high SAR, which displays a higher micropore volume, crystallinity, relative acid strength, and lower NAR as compared to the materials obtained using methods known in the state of the art. Importantly, this was achieved in absence of costly and undesired organics in the base treatment, such as TPABr or CTACI.

[0173] Examples 3-8

[0174] Examples 3-8 were made in the same manner as Example 2, with the exception that an inorganic salt was added during the first acid treatment and that the concentration of monosodium citrate in the first acid treatment was either 0.15 M or 0.10 M. The applied variations are summarized in Table 7. Table 7: Variations applied to the first acid treatment (step i) in Examples 2-8

[0175] The properties of the solids obtained from Examples 3-8, as described in Table 6, reveal that the addition of salts leads to a better preservation of intrinsic zeolitic properties, and the use of sodium salts did not negatively influence the NAR in the final product. Moreover, when examining the results at fixed acid concentration of 0.10 M (Examples 3-5) or 0.15 M (Examples 6-8), it proves that the use of sodium and potassium salts yield similar micropore volumes of >0.25 ml / g as compared to ammonium salts, yet concomitantly yield about 0.10 ml / g, i.e. 33-50%, more mesopore volume. In addition to this advantage in mesopore efficiency, sodium and potassium salts also prevent the release of undesired NH3 in the base step following the first acid treatment.

[0176] Example 9

[0177] Example 9 was synthesized exactly as Example 2, with the exception that the first acid treatment (step (i)) was executed in a gradual fashion. Accordingly, the first acid treatment was performed by suspending 25 g of P4 (CBV400) in 187 ml of demi water and heated to 95°C, after which over the course of 45 min 63 ml of 0.60 M of monosodium citrate was added dropwise in a gradual fashion. Afterwards, the suspension was left stirring at 95°C for another 15 min, followed by the separation and washing and the further base-acid-ion exchange-steam-acid treatment sequence (steps (ii), (iia), (iii), (iv), and (v)) as described for Example 2. The gradual manner of executing the first acid treatment enhanced the intrinsic zeolitic properties of the obtained material, as compared to the direct contacting of Example 2.

[0178] Example 10

[0179] Example 10 was synthesized exactly as Example 5, with the exception that instead of 63 ml of 2.4 M NaOH, 63 ml of 2.0 M KOH was added during the base treatment, and that during the base and the second acid treatment 1 M KNO3 was present in the suspension from the start of the treatments. Hence, at each step of the 3 treatments of the acid-base-acid sequence (steps (i), (ii), and (iia)) 1 M KNO3 was present.

[0180] Example 9 shows that the entire acid-base-acid sequence can be performed in an excess of potassium cations, yielding attractive mesoporosity and intrinsic zeolitic properties. Moreover, this approach enables to reach a lower sodium content than the other samples prior to steps iv and v, that is, prior to steaming and acid treatment (Table 8).

[0181] Comparative Experiment M

[0182] In Comparative Experiment M, only 3 of the 5 steps of the inventive process were executed, that is, by only executing steps (iii), (iv), and (v), without steps (i), (ii), or (iia). Hereto, 3 g of zeolite P4 (CBV 400) was ion exchanged in 30 ml of 0.5 M ammonium sulphate, reacted at 80°C for 1 h, followed by separation using Buchner filtration. This ion exchange procedure was repeated twice more, followed by drying overnight in air at 110°C. Next, the steaming (step (iv)) and acid treatment (step (v)) as described for Example 2 were executed.

[0183] Executing only the ion exchanging, steaming, and acid treatment on a low-SAR parent faujasite with UCS of ca. 24.50 A yielded a high-SAR USY material of high intrinsic properties, with a high Vmicro, low NAR, high relative acid strength, yet of limited mesopore volume around 0.20 ml / g. The properties of the obtained zeolite are described in Table 4. Hence, this process yields materials largely similar as the parent USY zeolites of the state of the art (P1 , P2, P5, Table 2) Experiment M and Examples 2 to 10 prior to step (iv) and step (v)

[0184] For selected samples the intermediate products obtained after ion exchange (Step (iii)) and before steaming and subsequent acid treatment were analyzed. Table 8 demonstrates that the effect of the addition of salt on the creation of mesopore volume is about 50% smaller before the steam and acid treatment, which makes the beneficial effect of the Na and K salts more surprising. In addition, Table 8 reveals that the SAR is generally around 7 to 8 mol / mol prior to the steam and acid treatment, which makes that roughly 25% of the alumina is removed from the bulk prior to steaming and acid treatment. Many inventive samples displayed up to sevenfold increased sodium contents, which is generally not be preferred. Yet surprisingly, after steam and acid treatment, the NAR was 0.00 as for the conventional non-mesoporised and non-base-treated zeolites (Table 2). Hence, not in the order of 0.03 to 0.07 as when the base treatment is executed on high SAR USY zeolites (Table 3).

[0185] Table 8 also reveals that the NAR of the mesoporised non-steamed Y zeolite can be lowered down to 0.01 mol / mol by working with the potassium salts and / or KOH as demonstrated in Examples 5, 8, 10.

[0186] Table 8: Overview of Y zeolite Examples derived from P4, prior to steaming and acid treatment. n.a.=not applicable The yield of the final acid treatment in H2SO4 following the steam treatment (step (v)), was in many cases higher than that of the sample prepared according to the method in the state of the art (Table 9). Surprisingly, the increased solid yields related better to the degree of mesopore volume (Figure 4), as compared to the amount of aluminum removed by the steam and subsequent acid treatment (steps (iv) and (v), Figure 5), implying that an altogether different -yet still unknownleaching mechanism to take place during the last acid treatment. Herein, the aluminum removed was calculated by the difference in aluminum content before and after steam and subsequent acid treatment. The enhanced yield of the final acid treatment (step (v)) enables to produce high-SAR USY zeolites at using less energy in the severe steaming step, as elaborated in Example 1 .

[0187] Table 9: Solid yields of the final H2SO4 acid treatment following the steam treatment for Experiment M and Examples 2 to 10.

[0188] Figure 3 shows the Vmicro and Vmeso values of the USY zeolites derived from Examples 2-19 (closed circles), non-base-treated materials (P1 -P5, M, empty diamonds), Comparative examples A-L, N, 0, and P (empty triangles), and mesoporous USY zeolites disclosed in the state of the art. It becomes clear that both US2004 / 0141911 and US5601798 feature either materials of limited mesoporosity (<0.25 ml / g) and / or of limited micropore volume (<0.24 ml / g). Materials obtained using existing methods (Comparative experiments), display that a variety of mesopore volumes can be achieved, yet that the Vmicro is never above 0.25 ml / g. Materials disclosed in Catalysis Today 235, 2014, 176-183, display relatively high micropore volumes at reported mesopore volumes, yet feature only materials with mesopore volumes >0.40 ml / g of SARs 25 and lower. Hence, as indicated by the samples complemented with SAR values, the state of the art does not disclose the novel USY zeolites having the claimed combination of at least mesopore volume, micropore volume and SAR. In Table 10, the unit cell size (UCS) as measured using ASTM D3942-19, the crystallinity relative to NaY, as measured using ASTM 3906, the volume of argon sorbed at 87K at relative pressure of p / p0=0.004 (Vmicro-Ar), in addition to the SAR, porosity, and acidity are displayed for selected samples. Only the materials obtained using the inventive process combine high mesoporosity with high intrinsic zeolitic properties, such as microporosity, crystallinity, and acidity.

[0189] Example 11

[0190] Example 7 was repeated except in that the concentration of mono-sodium citrate in step (i) was 0.20 M instead of 0.15 M, and the concentration of mono-sodium citrate in (step iia) was 0.10 M instead of 0.05 M, and that the final acid treatment in H2SO4 (step v) was not executed. The NAR of this intermediate USY zeolite was 0.05, the soda content was 0.3 wt%. See results in Table 10.

[0191] This example demonstrates that a low-SAR material with a relatively small unit cell size can be obtained as the second intermediate USY zeolite, featuring a unique combination of micropore volume, mesopore volume, and crystallinity.

[0192] Example 11 was repeated except in that the final acid step (step v) was executed according to Example 7, except using 0.25 M H2SO4 instead of 0.30 M. The NAR of this material was 0.00, the soda content was 0.0 wt%. See further results in

[0193] Table 10. This example shows that a novel mesoporous USY was prepared having a high SAR (>50 mol / mol) combined with high mesoporosity (>0.5 ml / g) and high microporosity (>0.25 ml / g). The unique nature of this sample is illustrated in Figures 3 ,8 and 9.

[0194] Example 12 was repeated except that the parent zeolite was a low-SAR USY provided by Jalon (P8), instead of P4. P8 is in the hydrogen form with unit cell size of 24.58 Angstrom and contains about 20% of extra-framework aluminium as compared to the bulk aluminium as assessed with 27AI MAS NMR. The content of aluminum as part of the framework is 80% relative to the total amount of aluminium in the bulk. The material obtained after step (v) displays all the preferred properties (Table 10), indicating that a zeolite with a unit cell size of 24.58 Angstrom is a suitable parent zeolite Y for the process of this invention. The NAR was 0.00 of this sample.

[0195] Comparative experiment Q

[0196] Example 12 was repeated except that the acid treatment step (iia) directly following the alkaline treatment was not performed and that step (v) was performed at 0.30 M instead of 0.25 M H2SO4. See other properties in Table 10.

[0197] The properties of this material are clearly inferior in terms of microporosity, crystallinity, and mesoporosity compared to that of Example 12, highlighting the value of the second acid step (iia), see also Figure 8.

[0198] Analysis using argon sorption at 87 K reveals that Example 12 features a Vmicro-Ar of 179 ml / g, that is about 83% as compared to non-mesoporised Comparative Experiment M (215 ml / g). This relates well to the micropore volume as determined by nitrogen sorption at 77 K where a retention of 85% was attained. In line with the nitrogen sorption-based Vmicro, the material obtained from Comparative Experiment Q shows a reduced Vmicro-Ar of 163 ml / g, that is roughly 10% lower as compared to Example 12. Hence, argon sorption confirms that the inventive USY materials display high zeolitic microporosity, and not those which amorphous materials such as, MCM-41 or SBA-15, may display when analysed using nitrogen sorption at 77 K, and that step (iia) is instrumental in maximizing the intrinsic zeolitic properties.

[0199] Example 14

[0200] Example 12 was repeated except that the molarity of H2SO4 in the final acid treatment step (v) was varied in the range of 0.15 to 0.30 M. This resulted in that the obtained USY zeolite had a varying SAR as shown in Figure 8. In Figure 8 also the resulting Vmicro is plotted. It shows that an optimum in Vmicro is achieved at a SAR of about 80. See also Table 11 . Comparative experiment R

[0201] Comparative experiment Q was repeated except that the molarity of H2SO4 in the final acid treatment step (v) was varied in the range of 0.25 to 0.40 M. This resulted in that the obtained USY zeolite had a varying SAR as a function of Vmicro

[0202] (Figure 8). See also Table 11 . From Table 11 , it can be concluded that a higher SAR is obtained at a similar concentration of H2SO4 according to the invention, as well as a higher solid yield of step (v) at fixed SAR level. This means that step (iia) not only makes the final acid step more effective (as less acid is needed to obtain the same SAR), it also makes the steaming step less energy consuming (as less precious material is lost), in line with the teachings of Example 1 .

[0203] Comparative experiment S

[0204] Example 12 was repeated except that instead of P4 (CBV400), P3 (CBV100) was used. The resulting material displayed an increased SAR and a high micropore volume (Table 10). Yet, the mesoporosity was similar to commercial materials such as P1 and P2, indicating that the inventive process is not suitable for parent zeolites with UCS of 24.65 Angstrom, and that the invention is specific for parent zeolites with unit cell sizes below 24.65 Angstrom.

[0205] Comparative experiment T

[0206] Example 12 was repeated except that instead of P4 (CBV400), P6 (CBV600) was used. The resulting material was completely amorphous (Table 10), indicating that the inventive process is most suitable for parent zeolites with unit cell sizes above 24.35 Angstrom.

[0207] Comparative experiment II

[0208] Example 12 was repeated except the acid treatment of Step (i) was replaced with the acid treatment described in Example 5 of WO2015100171 , yet executed at the same scale of Step (i) of Example 12. Accordingly, 25 g of anhydrous P4 (CBV400) was combined with deionized water to provide 125 g of 20 weight percent slurry. Next, 21 ,3 g of sodium sulfate was added to the slurry, which was agitated at 30°C for several minutes. Thereafter, 27.6 g of 20 percent sulfuric acid was added to the dispersion during agitation for 35 minutes. Next steps (ii-v) were executed as in Example 12.

[0209] The resulting USY after step (v) did not display more mesoporosity than conventional USY zeolites (Table 10), indicating that the presence of carboxylate anions in Step (i) is required to achieve the desired level of mesoporosity, and that the teachings of W02015100171 do not enable to yield the inventive materials disclosed herein.

[0210] Example 15

[0211] Example 15 was executed according to Example 12, except that in Step (i) 0.15 M mono-sodium EDTA (Na1 H3EDTA) was used instead of 0.20 M mono-sodium citrate. Na1 H3EDTA features 75% of protonic cations and is therefore according to the invention. The resulting USY material demonstrates the desired mesoporosity, microporosity, SAR, and crystallinity (Table 10). The NAR of this material was 0.00.

[0212] The USY materials obtained from Examples 12-15, Q-U, demonstrate that:

[0213] - The invention is effective using various organic salts and parent zeolites.

[0214] - The unit cell size of the parent zeolite needs to be lower than 24.65 and higher than 24.35 Angstrom to obtain favourable results.

[0215] - The acid in step (i) needs to be of carboxylic nature.

[0216] - The microporosity displays a trend as a function of SAR, with a maximum around 80 mol / mol (Figure 8).

[0217] - The microporosity is highest for the USY zeolites obtained in Examples 12 and 14 and much lower for Experiments Q and R. This highlights the value of the step (iia).

[0218] - Mesoporous materials obtained by alkaline-treatment of conventional high SAR USY zeolites (comparative experiments D, O, P) display lower crystallinity, and particularly strongly reduced crystallinity SAR values above 40 mol / mol (Figure 9). This is attributed to the relatively high tendency of high SAR USYs to amorphized in alkaline media. This relates well to disclosures in hydrocracking (WO2021 / 185721 ), where, at similar zeolite loading in the catalyst, the activity of alkaline-treated mesoporous USY zeolites was lower than that of the parent zeolites, and the reduction in activity becomes larger as a function of the SAR of the parent zeolite. - The mesoporous materials obtained by the invention display relatively constant crystallinities around 45% compared to NaY (See Figure 9).

[0219] - The mesoporous materials obtained by the invention display superior crystallinities as compared to the state of the art at SARs above 40 mol / mol, relating well to the observations in Figure 3 and Figure 6.

[0220] Examples 16

[0221] Steps (i), (ii), (iia), and (iii) of Example 11 were repeated except in that the scale was forty times larger, and that for steps (i), (ii), and (iia) soft water was used instead of RO water. Accordingly, a jacketed 50L reactor combined with a plate filter fitted with 25 plates of 20 cm x 20 cm cellulose depth plates was used to execute the treatments and subsequent separations. The NAR of this intermediate Y zeolite material was 0.06, the soda content was 0.6 wt%. See other properties in Table 10.

[0222] Example 17

[0223] The intermediate Y zeolite obtained in Example 16, was steamed (step iv), as described for Example 11 to obtain a intermediate steam modified USY. The NAR of this material was 0.05, the soda content was 0.5 wt%. See other properties in Table 10.

[0224] Example 18

[0225] The intermediate steam modified USY obtained in Example 17 was subjected to a final acid step (v) as in Example 7, yet with 0.20 M H2SO4 instead of 0.30 M. See other properties in Table 10.

[0226] Example 19

[0227] The intermediate steam modified USY obtained in Example 17 was subjected to a final acid step (v) as in Example 7, yet with 0.25 M H2SO4 instead of 0.30 M resulting in a higher SAR product than in Example 18. See other properties in Table 10.

[0228] The results demonstrate that similar or better materials can be obtained when moving to larger scales of Steps (i, ii, iia, and iii) and that the more cost-attractive soft water can be suitably used. This is in contrast with the state of the art, as mesoporisation by base treatment of high-SAR USY zeolites gives rise to substantial process difficulties, such as separation complications and resulting amorphization, which makes that suitable properties are typically only obtained at the gram scale, and not at the kg or ton scale.

[0229] Moreover, the properties of the sample from Example 16, and the fresh sample from Example 7 included in Table 8, (hence the unsteamed materials), are attractive as they feature sizable gains in micropore volume and surface area as compared to those derived from similar parent materials disclosed in US2022073359 illustrated in Figures 10 and 11.

[0230] Paradigm shift in the synthesis of mesoporous USY zeolites

[0231] The fundamental difference of the inventive process can be suitably illustrated by closely evaluating the unit cell size, SAR, and mesopore volume of inventive and state of the art materials (Figure 7).

[0232] Within the state of the art on conventional non-mesoporised USY zeolites (dotted arrows), first a reduction in the UCS is achieved (moving from P3 to P4, on to P6). Next, dealumination of the bulk is achieved, yielding P1 , P2, and P5. During this process some mesoporosity is formed. Existing methods to yield mesoporous high- SAR USY zeolites treat the high-SAR conventional USYs in alkaline media (typically using organic additives), yielding samples H and D (dashed arrows).

[0233] In contrast, the inventive process mesoporises in steps (i-iii) a low-SAR Y zeolites, followed by further lowering of the UCS, and only then followed by bulk dealumination (solid arrows). This has at advantage:

[0234] 1 ) A more efficient use of energy (see Example 1 ).

[0235] 2) No need for additional ion exchange and calcination (see Example 1 ).

[0236] 3) The mesoporisation can be done in the absence or organic additives and using low-cost soft water.

[0237] 4) Salts based on combinations of sodium, potassium, chloride, nitrate, and sulfates, can be used to enhance material properties, leaching efficiency, safety, and improve washing efficiency. 5) Unique low-SAR intermediates are obtained after Step (iii) (see Example 16) and after Step (iv) (see Example 17).

[0238] 6) Unique high-SAR USY are made based on the high intrinsic properties and low NARs, particularly at high SARs (see Examples 18+19).

[0239] Table 10: Properties of various inventive examples and comparative experiments. Table 11 Composition and properties of various samples exposed to different end concentrations of step (v).

Claims

CLAIMS1 . Process to obtain a USY zeolite having a high mesoporosity starting from a parent zeolite Y with a unit cell in the range of 24.45 to 24.60 A and having a SiO2 / Al2O3 ratio of between 4 and 8 mol / mol, comprising the following steps:(i) contacting the parent zeolite Y with an aqueous solution comprising a carboxylate salt, of which at least 40 mol% and at most 80 mol% of the cations are protons and wherein the pH is in the range of 1 to 5 to obtain an intermediate acid-treated zeolite Y,(ii) contacting the intermediate acid-treated zeolite Y with a solid base or a base solution to obtain an intermediate acid-alkaline-treated zeolite Y, (iia) wherein the obtained intermediate acid-alkaline-treated zeolite Y of step (ii) is subjected to an additional acid treatment step (iia) by contacting the intermediate acid-alkaline-treated zeolite Y of step (ii) with an aqueous solution comprising a carboxylate salt, of which at least 40 mol% and at most 80 mol% of the cations are protons, and wherein the pH is in the range of 1 to 5 to obtain an intermediate acid-alkaline-acid-treated zeolite Y,(iii) contacting the intermediate acid-alkaline-acid-treated zeolite Y with an aqueous solution containing an ammonium salt and obtaining a zeolite Y in the ammonium form,(iv) subjecting the zeolite Y in the ammonium form to a steam treatment to obtain an intermediate steam modified USY zeolite, and(v) contacting the intermediate steam modified USY zeolite with an acid to obtain the USY zeolite having a high mesoporosity.

2. Process according to claim 1 , wherein the parent zeolite-Y is obtained by ion exchange to the ammonium form of a NaY zeolite followed by a mild steam treatment, wherein the mild steam treatment is performed at a temperature of below 550 °C and wherein the obtained parent zeolite-Y is in the protonic cation form.

3. Process according to claim 1 , wherein the parent zeolite Y has a mesopore volume of between 0.02 and 0.10 ml / g and is in the hydrogen, sodium or ammonium cation form and preferably in the hydrogen cation form.

4. Process according to any one of claims 1 -3, wherein the content of aluminum as part of the framework is below 90% relative to the total amount of aluminium in the bulk.

5. Process according to any one of claims 1 -4, wherein the anion of the carboxylate salt in step (i) and / or in step (iia) is an anion of one or more of the following acids: oxalic acid, malic acid, citric acid, acetic acid, benzoic acid, lactic acid, formic acid, ethylenediaminetetraacetic acid, and tartaric acid and wherein the cation of the carboxylate salt in step (i) and / or in step (iia) is an alkali metal cation, a water-soluble alkaline earth metal cation or an ammonium cation and combinations thereof.

6. Process according to any one claims of 1 to 5, wherein in step (i) and / or Step (ii) and / or Step (iia) an inorganic salt is present having cations chosen from sodium and / or potassium and anions chosen from chloride, nitrate and / or sulfate.

7. The process of any one of claims 1 to 6, wherein the solid base or the base solution in step (ii) is an inorganic base chosen from LiOH, NaOH, KOH, CsOH, and / or NH4OH.

8. Process according to any one of claims 1 -7, wherein the base treatment of step (ii) is executed in a gradual contacting as performed in a time period of between 15 seconds and 60 minutes, wherein the solid base or base solution is added to the intermediate acid-treated zeolite Y at a rate of below 5 mmol base per gram of intermediate acid-treated zeolite Y per minute and wherein between 0.1 and 15 mmol base is added in total pergram of intermediate acid-treated zeolite Y and wherein the pH is between 9 and 13.5.

9. The process according to any one of claims 1 -8, wherein the acid in step (v) is a mineral acid, and wherein the pH is between -2 and 5 and wherein the mineral acid is HNO3, HCI, H2SO4, H3BO4, H3PO4, HF and / or NH4F.

10. The process according to any one of claims 1 -9, wherein the acid treatment of step (v) is executed in a gradual contacting in a time period of between 15 seconds and 300 minutes, wherein a solid acid or acid solution is added to the intermediate steam modified USY zeolite at a rate of below 3 mmol acid per gram of intermediate steam modified USY zeolite per minute and wherein between 0.1 and 10 mmol acid is added in total per gram of intermediate steam modified treated USY zeolite.11 . The process according to any one of claims 1 -10, wherein step (i) and / or step (iia) is performed in a gradual contacting in a time period of between 15 seconds and 300 minutes, wherein the aqueous solution comprising a carboxylate salt is added to the parent zeolite Y at a rate of below 3 mmol carboxylate salt per gram of parent zeolite Y per minute and wherein between 0.1 and 10 mmol of carboxylate salt is added in total per gram of parent zeolite Y.

12. Process according to claim 11 , wherein the amount of carboxylate salt per gram of intermediate acid-alkaline-treated zeolite Y in step (iia) is between 20-50% lower than the amount of carboxylate salt per gram of the parent zeolite Y in step (i).

13. The process according to any one of claims 1 -12, wherein the contacting in step (i) is performed in a suspension of the parent zeolite Y and the aqueous solution,wherein the acid-treated zeolite Y is separated from the suspension using a plate filter resulting in a cake of the acid-treated zeolite Y, wherein in step (ii) is performed starting with the acid-treated zeolite Y as present as the cake in the plate filter resulting in a cake of the intermediate acid-alkaline-treated zeolite Y in the plate filter, wherein step (iia) is performed is performed starting with the acid-alkaline treated zeolite Y as present as the cake in the plate filter resulting in a cake of the intermediate acid-alkaline-acid-treated zeolite Y in the plate filter, and wherein the cake obtained in step (i), (ii) and (iia) is washed before performing the next step and wherein between performing step (i) and (ii) and between step (ii) and (iia) no drying of the cake takes place.

14. A process according to claim 13, wherein the cake is washed with an aluminum-free and silicon-free aqueous solution of pH 6-9 not containing more than 0.1 g / L of silicon and aluminum combined and wherein a resulting washing solutions is obtained after washing.

15. A process according to claim 14, wherein the washing aqueous solution comprises sodium and potassium salts.

16. A process according to any one of claims 14-15, wherein the washing is continued until the resulting aqueous washing solution contains less than 3 g / L of silicon or aluminum combined.

17. A process according to any one of claims 1 -16, wherein in steps (i), (ii) and (iia) the mesopore volume increases relative to the parent zeolite Y with a volume of between 0.10 and 0.50 ml / g and in steps (iv) and (v) with a volume of between 0.10 and 0.30 ml / g.

18. A process according to any one of claims 1 -17 wherein the SiO2 / Al2O3 ratio (SAR) after step (i) is between 7 and 11 mol / mol, after step (ii) isbetween 5 and 8 mol / mol, after step (iia) is between 5 and 10 mol / mol and after step (v) is above 20 mol / mol.

19. A process according to any one of claims 1 -18, wherein the USY zeolite obtained in step (v) has a micropore volume greater than 0.24 ml / g, a mesopore volume greater than 0.30 ml / g, and a SiO2 / Al2O3 ratio (SAR) greater than 40 mol / mol, a unit cell size smaller than 24.45 A, and a relative crystallinity of at least 40 % relative to a NaY.

20. A USY zeolite having a micropore volume greater than 0.24 ml / g, a mesopore volume greater than 0.30 ml / g, and a SiO2 / Al2O3 ratio (SAR) greater than 40 mol / mol, a unit cell size smaller than 24.45 A, and a relative crystallinity of at least 40 % relative to a NaY.21 . The USY zeolite according to claim 20, wherein the micropore volume is greater than 0.26 ml / g.

22. The USY zeolite according to any one of claims 20-21 , wherein the SiO2 / Al2O3 ratio (SAR) is between 40 and 150.

23. The USY zeolite according to any one of claims 20-22, wherein the zeolite USY has a total surface area greater than 600 m2 / g.

24. The USY zeolite according to any one of claims 20-23, wherein the micropore volume measured by argon (Vmicro-Ar) is greater than 165 ml / g.

25. The USY zeolite according to any one of claims 20-24, wherein the soda (Na2O) to alumina (AI2O3) molar ratio (NAR) of the USY zeolite is below 0.03 mol / mol.

26. The USY zeolite according to any one of claims 20-25 as obtainable by the process of any one of claims 1 -18 or the process of any one of claims 29 and 33.

27. An intermediate USY zeolite having a micropore volume greater than 0.17 ml / g and a mesopore volume greater than 0.30 ml / g, a SiO2 / Al2O3 ratio of 5 to 10 mol / mol, a unit cell size smaller than 24.45 A, a total surface area greater than 500 m^ / g, and a relative crystallinity of at least 35 % relative to a NaY.

28. An intermediate USY zeolite according to claim 27 as obtainable by the process of any one of claims 1-18 except that step (v) is not performed.

29. A process to prepare a USY zeolite according to any one of claims 20-25 by contacting the intermediate USY zeolite according to any one of claims 27 and 28 with an acid.

30. The process according to claim 29, wherein the acid is HNO3, HCI and / or H2SO4.and wherein the pH is between -2 and 5.31 . An intermediate Y zeolite in the ammonium cation form having a micropore volume greater than 0.28 ml / g and a mesopore volume greater than 0.15 ml / g as measured by nitrogen physisorption, a SiO2 / Al2O3 ratio of 5 to 12 mol / mol, a unit cell size smaller than 24.55 A and larger than 24.45 A, a total surface area greater than 700 m2 / g, a NAR below 0.15, and a relative crystallinity of at least 75 % relative to a NaY.

32. An intermediate Y zeolite according to claim 31 as obtainable by the process of any one of claims 1-18 except that steps (iv) and (v) are not performed.

33. A process to prepare a USY zeolite according to any one of claims 20-25 by subjecting the intermediate Y zeolite according to any one of claims 31and 32 to a steam treatment to obtain an intermediate steam modified USY zeolite, and contacting the intermediate steam modified USY zeolite with an acid.

34. The process according to claim 33, wherein the acid is HNO3, HCI and / or H2SO4 and wherein the pH is between -2 and 5.

35. A hydrocracking catalyst comprising a USY zeolite according to any one of claims 20-25, a binder and an old IUPAC Group VIII metal.

36. The hydrocracking catalyst according to claim 35, wherein the metal is platinum, palladium, nickel or cobalt.

37. The hydrocracking catalyst according to claim 36, wherein the binder is silica, alumina and amorphous silica-alumina.

38. A process to prepare middle distillates by contacting a hydrocarbonaceous feedstock boiling for more than 90 wt% above 350°C under hydrocracking conditions with a hydrocracking catalyst according to any one of claims 35-37.

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