Process of manufacturing of alkali o-cresolate or alkali pxylenolate

Abstract

The present invention relates to a process of manufacturing alkali o- cresolate or alkali p-xylenolate, respectively of o-cresol or p-xylenol. It has been shown that this process using an extruder for the reaction of the compound of the formula (II) with sodium hydroxide or potassium hydroxide is very advantages and enables significantly faster reaction times and continuous process. Formula (II), wherein R is either H or CH3 and Y is SO3H or SO3 -X+ or Cl and X is either Na or K, preferably Na.

Description

[0001] PROCESS OF MANUFACTURING OF ALKALI O-CRESOLATE OR ALKALI P- XYLENOLATE

[0002] Technical Field

[0003] The present invention relates to the field of production of o-cresol and p- xylenol.

[0004] Background of the invention

[0005] The compounds o-cresol (=2-methyl phenol) and p-xylenol (=2,5-dimethyl- phenol) are highly valuated ingredients which are used for different purposes. Xylenols are used as starting materials for pesticides, antioxidants or pharmaceuticals

[0006] Cresols are precursors or synthetic intermediates to other compounds and materials, including plastics, pesticides, pharmaceuticals, and dyes.

[0007] The compound o-cresol is a very interesting as it is used as an industrial solvent and in disinfectants and fungicides or used to make synthetic resins herbicides, pesticides, dyes, drugs, antioxidants, perfumes, and other chemicals and is used as a food antioxidant, textile scouring agent, surfactant, metal cleaner, and ore flotation agent, used as ingredient in cleaning compounds, degreasers, paints and paint strippers, adhesives, fiber treatment, wood preservatives, and cutting oils.

[0008] The compound p-xylenol, is used for the synthesis of pH indicators xylenolphthalein, xylenol blue or bromo xylenol blue for example as well as medicine and the main raw material for gemfibrozil which can be used as medicine to treat abnormal blood lipid levels.

[0009] The compound p-xylenol is of key interest for the large-scale industrial synthesis of 2,3,6-trimethylphenol or 2,3,5-trimethylphenol, or 2,3,5- trimethylhydroquinone, or alpha-tocopherol.

[0010] Presently, 2,5-dimethylphenol is prepared by alkali fusion of sulfonated p- xylene using a batch type process. The alkali fusion is a process which is of highest concerns in view to corrosion and safety issues when the process is a batch process.

[0011] For example, CN 102627531 discloses such a batch process.

[0012] CN 114805034 discloses a process in which in a first step sodium 2,5- dimethyl benzene sulphonate and a strong base are mixed in a rake dryer to get a very fine powder (1 -5 micrometre) after 5 hours of grinding, sieving and drying. In a second step this powder is then transferred to a spiral pipe reactor and reacted during a lengthy time of 1 to 5 hours at high temperature to yield in a third step by acid quenching p-xylenol. Due to the use of a rake dryer and a spiral pipe the disclosed process is very slow and particular requires the preparation of fine powder in the first step.

[0013] The use of extruders for mixing and compounding thermoplastic material is known in the field of thermoplastics.

[0014] Summary of the invention

[0015] The problem to be solved is to find a process for preparing alkali o- cresolate or alkali p-xylenolate in a fast, efficient way without the need to form a very fine powder by a lengthy drying and grinding process.

[0016] Surprisingly, it has been found that the process of claim 1 offers a solution to this problem.

[0017] The use of an extruder for melting and reacting the compound of the formula (II) and the base XOH is very advantageous, as it does not require to grind the sodium 2,5-dimethyl benzene sulphonate and the base XOH prior to the reaction in step b) and is significantly faster (minutes instead of hours) the known process. Despite the shorter reaction time high yield and conversion could be observed. Due to the shorter exposure to high temperatures in the reaction step b) the amounts of undesired degradation products are reduced.

[0018] The process of the invention is highly advantageous in view of reduction of cost for energy, time as well as safety risks during production. The possibility of performing the process as a full continuous process, these advantages become even more pronounced.

[0019] Further aspects of the invention are subject of further independent claims. Particularly preferred embodiments are subject of dependent claims. Detailed description of the invention

[0020] In a first aspect the present invention relates to a process for the manufacture of a compound of the formula (I) from a compound of the formula (II) comprising the steps a) providing the compound of the formula (II) b) melting and reacting the compound of the formula (II) with XOH in an extruder 1 at a temperature of above the melting point of XOH, particularly between 320°C and 450°C, more particularly between 330°C and 450°C, even more particularly between 360°C and 450°C, preferably between 360°C and 420°C, more preferably between 380°C and 400°C, to yield the compound of the formula (I); characterized in that R is either H or CH3 and Y is SO3H or SOs'X+or Cl and X is either Na or K, preferably Na.

[0021] For sake of clarity, some terms used in the present document are defined as follows:

[0022] In case identical labels for symbols or groups are present in several formulae, in the present document, the definition of said group or symbol made in the context of one specific formula applies also to other formulae which comprises the same said label.

[0023] As melting point of a specific substance in this document is used as the temperature where said substance is melting at ambient temperature (23°C) and pressure (1013 mbar).

[0024] The term "essentially free of water" is used in this document to mean that the substance at issue does comprise only traces of water, particularly not more than 10% by weight. Step a)

[0025] In step a), a compound of the formula (II) is provided.

[0026] The compound of the formula (II) is selected from the groups consisting of compounds of the formula (l-A), (l-B) and (l-C)

[0027] (Il-A) (H-B) (ll-C).

[0028] The compound of the formula (I l-A) can be prepared by sulfonation of the compound of the formula (III), particularly by the reaction of sulfuric acid and the compound of the formula (III). Particularly suitable is concentrated sulfuric acid. Said reaction typically yields a mixture of isomers comprising the compound of the formula (I l-A). The person skilled in the art knows that the amount of the compound of the formula (I l-A) in said mixture strongly depends on the reaction conditions in the sulfonation.

[0029] In one of the embodiments an isomeric mixture comprising the compound of formula (I l-A) is used for the process of invention. In another embodiment, isomer (I l-A) is isolated from said mixture and used for the process of invention.

[0030] The compound of the formula (I l-B) can be prepared by neutralizing the compound of the formula (I l-A), particularly as shown later in this document in more detail.

[0031] The compound of the formula (I l-C) can be prepared from the reaction of the compound of the formula (III) and chlorine.

[0032] Said reaction is known by the person skilled in the art and yields typically a mixture of isomers comprising the compound of formula (I l-C). In one of the embodiments an isomeric mixture comprising the compound of formula (I l-C) is used for the process of invention. In another embodiment, isomer ( I l-C) is isolated from said mixture and used for the process of invention.

[0033] It is preferred that the compound of formula (II) is the compound either of the formula (I l-A) or of the formula (I l-B).

[0034] The compound of the formula (II) is selected from the groups consisting of

[0035] It is preferred that R = CH3.

[0036] So, preferred compound of the formula (II) is compound of the formula (II- 0) and, accordingly, the preferred compound of the formula (I) is the compound of the formula (1-0) It is, furthermore, preferred that in that Y = SO3'X+, particularly SO3'Na+.

[0037] It more preferred that compound of the formula (II) is the compound of the formula (I l-B), particularly (II-B2), preferably (ll-BB) Accordingly, the preferred compound of formula (I) is the compound of the formula (l-A), preferably of the formula (l-BB).

[0038]

[0039] From the class of potassium salts, the most preferred compound of formula (II) is the compound of the formula (ll-CC) and the most preferred compound of formula (I) is the compound of the formula (l-CC) Reaction Step b)

[0040] In step b), the compound of the formula (II) is melted and reacted with XOH in an extruder 1 at a temperature of above the melting point of XOH, particularly between 320°C and 450°C, more particularly between 330°C and 450°C, even more particularly between 360°C and 450°C, preferably between 360°C and 420°C, more preferably between 380°C and 400°C, to yield the compound of the formula (I).

[0041] The melting point of NaOH is about 320°C and of KOH is 360°C.

[0042] Hence, it is obvious that the temperature ranging between 320°C and 360°C, as part of the temperature ranges indicated above, are suited only in case of NaOH being used for the reaction.

[0043] It is preferred that step b) of melting and reacting the compound of the formula (II) with XOH is performed in the presence of a molar excess of XOH, so that the molar ratio of XOH and / or to the compound of the formula (II) is > 2, particularly between 2 and 4, preferably between 2 and 3, more preferably between 3 and 2.5.

[0044] More preferred is said molar ratio in the range of 2.01 to 3.99, preferably of 2.01 to 2.99, more preferably of 2.01 to 2.49.

[0045] It is also possible that a mixture of NaOH and KOH might be used. However, it is most preferred that NaOH alone is used.

[0046] Temperatures of above 450°C in step b) are principally possible.

[0047] Despite the higher temperature would lead to faster reaction time, hence, enabling principally shorter residence time in the extruder, it is advised, however, to perform the reaction in step b) not at too high temperatures as this leads to the formation of higher amounts of degradation products of the compound of the formula (I) or (II). The formation of such degradation products is particularly pronounced if extended residence time of compound of the formula (II), respectively (I), are used.

[0048] The residence time of the compound of the formula (II), respectively (I), are controlled by the speed of the extrusion speed, i.e. by the rotational speed of the extrusion screw. If it is too short, the rection is not complete, and significant amounts of unreacted compounds of the formula (II) are observed in the product leaving the extruder. If it is too long, particularly at elevated temperature, particularly higher that 450°C, there exists the risk that undesired side products are formed by thermal degradation of the compound of the formula (I) or (II).

[0049] The reaction of step b) is performed inside an extruder.

[0050] The extruder 1 comprises comprising at least -a casing 6

[0051] -a cavity 5 inside the casing 6

[0052] -a extruder screw 7 inside the cavity 5

[0053] -an inlet 2 for the compound of the formula (II)

[0054] -an outlet 3 for the compound of the formula (I)

[0055] -a mixture of XOH and the compound of the formula (II) inside the cavity 5.

[0056] In other words, the extruder comprising XOH and the compound of the formula (II) represents an apparatus which produces the compound of the formula (I)-

[0057] The compound of the formula (II) can be NaOH, can be introduced to the extruder 1 by the inlet 2 of the extruder.

[0058] The base XOH, preferably NaOH, can be introduced to the extruder 1 either as a mixture with the compound of the formula (II) by the inlet of the extruder 2 or, preferably, by a separate inlet 4 for KOH and / or NaOH.

[0059] It is preferred that XOH is transferred to the extruder in form of solid XOH or in form of a melt of XOH. Preferably, XOH is introduced as melt into the extruder.

[0060] Preferably, the extruder 1 further comprises at heating elements 9 which allows an adjustment of the temperature of the reaction mixture of XOH and compound of the formula (II) within the extruder 1 . It is particularly advantageous if said reaction mixture shows a temperature gradient extending from lower temperatures near the inlet 2 entry of the extruder to higher temperatures at the outlet 2 of the extruder. It is preferred that differences of temperatures of this temperature gradient is at least 20 K, preferably at least 40 K.

[0061] Therefore, it is preferred that the temperature of the material in the region of the inlet 2 of the extruder 1 is lower than in the region of the outlet 3 of the extruder 1 . During the reaction some gases are produced. It is, therefore, further preferred that the extruder comprises at least one of the degassing outlet 10. This degassing outlet allows said gases to escape from the extruder. The position of such a degassing outlet 10 along the axis of the extruder are chosen so that the gas formed during the reaction does not form to high pressures inside the extrude, which might be critical in view of safety. Typically said degassing outlet 10 comprises a mean to control the pressure release, e.g. pressure control valve 1 1 .

[0062] The extruder 1 is either a single screw or a multi screw extruder.

[0063] Compared to single screw extruders, multi screw extruders are more efficient in providing homogeneous mixing of the reaction partners. Mixing efficacy of single screw extruders could be improved by using mixing elements but not as effective as multi screw extruders. Larger variety of multi screw extruders are available that may vary in construction, could have parallel or conical screws that may rotate in same direction (corotating) or opposite direction (counter-rotating), and have different degree of intermeshing. In contrast to a spiral pipe reactor which has no moving internal parts and, hence, mixing is only made by fluid flow itself, an extruder has an active rotating screw which is very efficient in mixing. Hence, an extruder manages to handle also very course materials to achieve homogenous mixtures which is not the case with spiral pipe reactors. It has been uis known that an extruder is very efficient.

[0064] It is preferred that the extruder 1 is a twin or triple screw extruder.

[0065] Neutralisation Step

[0066] In the case where the compound of the formula (II) is the compound of the formula (I l-B), particularly of the formula (I I-B2), preferably of the formula (I l-BB), said compound is preferably prepared by neutralization of the compound of the formula (I l-A) or (II-A2), respectively.

[0067] The neutralization is preferably performed by the reaction with NaOH and / or KOH, preferably by NaOH.

[0068] Said neutralization of compound of the formula (I l-B) can be performed in the extruder or can be performed outside of the extruder.

[0069] In one of these embodiments, the neutralization reaction is performed in an extruder.

[0070] Hence, it is preferred that the compound of formula (II) is compound of the formula (I l-B) which is prepared by step aO) aO) neutralizing a compound of the formula (I l-A), particularly of the formula (II-A2), with XOH in an extruder at a temperature of between 100°C and 200°C, particularly between 100°C and 180°C, more particularly between 100°C and 150°C, preferably between 110°C and 130°C, to f

[0071] In one of the embodiments, the neutralization step aO) is performed in the same extruder as the step b). However, in that case it is preferred that the neutralization is performed near in the section close to the inlet of the extruder, preferably at a lower temperature than the reaction step b) which occurs further downstream in the extruder, i.e. closer to the outlet of the extruder.

[0072] In a preferred manner, however, the neutralization step aO) is preferred in a separate extruder.

[0073] In other words, it is preferred that the step of neutralizing (aO) is performed in a first extruder 1 a and step b) of melt reaction is performed in a second extruder 1 b and that the compound of the formula (II) is transferred from the outlet 3a of first extruder 1 a to the inlet 2b of the second extruder 1 b.

[0074] It is very preferred that the transfer of material between the first extruder 1 a and the second extruder 1 b is performed by a connection means 12 which is closed towards the environment.

[0075] This allows the possibility to enable the process for the manufacture of a compound of the formula (I) from a compound of the formula (II) to be a continuous process.

[0076] It is preferred that the step aO) of neutralizing the compound of the formula (II) with sodium hydroxide and / or potassium hydroxide is performed in the presence of a molar excess of XOH, so that the molar ratio of XOH to the compound of the formula (II) is > 1 , particularly between 1 and 2, preferably between 1 and 1 .5, more preferably between 1 and 1 .25.

[0077] More preferred is said molar ratio in the range of 1 .01 to 1 .99, preferably of 1 .01 to 1 .49, more preferably of 1 .01 to 1 .24.

[0078] The compound of the formula (I l-A), particularly of formula (I I-A2), are fed to the extruder preferably at a temperature of between 100°C and 200°C, particularly between 100°C and 180°C, more particularly between 100°C and 150°C, preferably between 110°C and 130°C. At this temperature the compound of the formula (I l-A), particularly of formula (I I-A2), form a viscous liquid.

[0079] The base XOH is fed to the extruder preferably as pearls or pellets of several millimeters, as commercially available Due to the use of an extruder, coarse particle up to several millimeters of compound of the formula (I l-A) or (II-A2) or XOH can be used without any problems. Hence, no lengthy grinding or powdering is needed.

[0080] It is also possible that a mixture of NaOH and KOH might be used for the neutralization step aO).

[0081] However, it is most preferred that NaOH alone is used.

[0082] By the neutralization reaction between the compound of the formula ( I l-A) or (II-A2), respectively, and the base XOH, water is formed in a stoechiometric amount.

[0083] As the presence of large amount of water is unfavorable in the reaction of step b) the neutralization step aO) is performed at elevated temperature, i.e. at a temperature higher than 100°C. Temperatures of above 200°C in step aO) are principally possible. However, it is advised to perform the neutralization aO) not at too high temperatures as this might to lead to a significant built-up of gas pressure which might lead to safety problems.

[0084] As the reaction step b) is performed at elevated temperatures, it is highly advisable to avoid or reduce the amount of water, forming steam (i.e. water vapor) at the reaction temperature, as much as possible in the starting products, particularly in the compound of the formula (II) and XOH. As NaOH and KOH are highly hygroscopic, it is preferred to store this compound in a water and vapor- tight container prior to the use and perform the whole process of the present invention in a closed and / or under inert atmosphere. It is also preferably that the starting materials are water-free or at least essentially free of water.

[0085] The residence time of the compound of the formula (II), respectively (I), are controlled by the speed of the extrusion speed, i.e. by the rotational speed of the extrusion screw. If it is too short, the rection is not complete, and significant amounts of unreacted compounds of the formula (II) are observed in the product leaving the extruder. If it is too long, particularly at elevated temperature, particularly higher that 450°C, there exists the risk that undesired side products are formed by thermal degradation of the compound of the formula (I) or (II).

[0086] It has been observed that the residence time in the extruder 1 a for the neutralization step aO) could be significantly shorter than the residence time in the extruder 1 b for the reaction step b) as the neutralization is a very fast reaction which is significantly faster even at lower temperature than the reaction of step b).

[0087] It has been found that the residence time in the first extruder 1 a are typically less than a minute, particularly between 30 second and 2 minutes, preferably between 30 seconds and 60 seconds.

[0088] It has been found that the residence time in the second extruder 1 b are typically several minutes, particularly between 3 and 30 minutes, preferably between 10 and 20 minutes.

[0089] For better timing of the steps aO) and b) in the framework of a continuous process, the residence time in the first extruder can be extended so that the residence time in both extruders 1 a and 1 b are the same, i.e. of typically several minutes, particularly between 3 and 30 minutes, preferably between 10 and 20 minutes. Such an extension of the residence time in the first extruder 1 a is not very detrimental as the decomposition reactions are not significantly pronounced, at the relative low temperature in first extruder 1 a.

[0090] To optimize productivity and reduction of production cost, it is preferred that the whole process of the invention is a continuous process. This goal easily can be reached by the described features as described above.

[0091] In a preferred embodiment, the material leaving the extruder 1 , particularly the second extruder 1 b, is transferred to a heated vessel, particular to a heated tubular reactor or pipe reactor or spiral pipe reactor. It is advantageous to heat said heated vessel to the same temperature range as the second extruder. By residing the product in said heated vessel for an additional time, a higher yield may be obtained and / or the extruder(s) to be allowed to operate at higher extruding speed which leads to higher product output of the whole process equipment.

[0092] It is preferred that the reaction product, i.e. the compound of the formula (I), particularly together with excess of molten XOH is transferred after the step b) to a vessel 13 comprising water, particularly into an aqueous sulphite solution, preferably an aqueous solution of Na2SOs. Due to its limited solubility in water the compound of the formula (I) can be easily isolated, for example by means of a filter or a frit. If desired, the so isolated compound of formula (I) can be further purified.

[0093] It is preferred that this transfer is realized by a connection means 22, such as a tube, between the outlet of the extruder 3, particularly the outlet of the second extruder 3b, and the vessel with water 13.

[0094] To allow a smooth reaction, and constant mass flow, preferably in continuous way, it is preferred that pumps are used to feed starting products and / or to expedite the product formed out of the extruder. Preferred pumps are gear or screw pumps.

[0095] It is obvious to the person skilled in the art, that all parts of the extruder, eventual existing pipes, tubes leading to or from the extruder 1 or pumps involved in the mass flow, being in the contact with the starting product, the reaction mixture or products are chosen so to be made out of a material which is chemically resistant to the respective chemicals in contact at the temperatures used in operation.

[0096] The compound of the formula (I), particularly formula (l-BB) or (l-CC), preferably (l-BB) can be used to prepare the compound of the formula (IV), particularly

[0097] Therefore, a further aspect of the present invention is a process of manufacturing of a compound of the formula (IV), particularly of the formula (IV-B), characterized in that the process comprises the step i) preparing a compound of the formula (I), particularly of the formula (I-

[0098] 0), by a process as discussed above in great detail, followed by a step c) acidifying the compound of formula (I), particularly of the formula (1-0) with an acid to yield the compound of the formula (IV), particularly of the formula (IV-B) wherein

[0099] R is either H or CH3, preferably CH3.

[0100] The acid used in step c) for acidifying are typically inorganic acids, particularly hydrochloric acid or sulfuric acid, preferably diluted HCI or H2SO4.

[0101] It is advantageous that compound of the formula (I) is acidified in water to obtain a pH of 5 or lower.

[0102] Particularly suitable is the use of gaseous SO2 or CO2 to form an "aqueous SO2 solution" or "CO2 solution", respectively sulfurous acid or carbonic acid.

[0103] As shown above, the use of extruders is a key element for the advantages of the described process very advantageous for the process for the manufacture of a compound of the formula (I) or of the compound of the formula (IV), respectively.

[0104] Hence, in a further aspect, the present invention relates to the use of an extruder 1 in the manufacturing of the compound of the formula (I) or (IV)

[0105] R is either H or CH3, preferably CH3 and X is either Na or K, preferably Na.

[0106] The preferred embodiments of compound of formulae (l)= and IV have discussed above already in great details.

[0107] Figures

[0108] In the following the invention, and particular preferred embodiments thereof, are described in more details in more details. It is stressed that only elements necessary for the understanding are shown. Same elements are shown with the same reference signs in different figures. Furthermore, it is stressed that the figures are schematic and particularly do not relate to real size and proportions.

[0109] Figure 1 shows schematically view of a generic extruder 1 suitable for the process of the invention. The compound of the formula (II) is introduced through an inlet 2 of the extruder 1 where the melting and reaction step b) at a temperature of above the melting point of XOH, particularly between 320°C and 450°C, more particularly between 330°C and 450°C, even more particularly between 360°C and 450°C, preferably between 360°C and 420°C, more preferably between 380°C and 400°C, to yield the compound of the formula (I), is performed and compound of the formula (I) is leaving the extruder 1 through the outlet 3 of the extruder.

[0110] The base XOH might be feed to the extruder by a separate inlet (inlet for KOH and / or NaOH 4) or directly with the compound of the formula (II) by the inlet 2 to the extruder. In the later case, a premix of XOH and compound of the formula (II) is formed prior to entering the extruder. It is preferred that XOH, particularly NaOH, is introduced as a melt to the extruder 1 .

[0111] Figure 2 shows in a schematic manner more details of figure 1 in a cross- sectional view of the embodiment with a separate inlet for XOH. The extruder 1 comprises a cavity 5 surrounded by a casing 6. Inside the cavity 5, a screw 7 of the extruder is localized. The compound of the formula (II), respectively XOH, is introduced through the inlet 2 and the inlet 4 for KOH and / or NaOH into the cavity 5 of the extruder. It is preferred that XOH, preferably particularly NaOH, is introduced as a melt to the extruder 1 . The screw 7 is rotated (indicated by arrow

[0112] A) by a motor 8 around its longitudinal axis. By the rotating action of the screw 7 the compound of formula (II) and XOH are thoroughly mixed and transported along the axis from the entry to the outlet of the extruder (indicated by the arrow

[0113] B). The heating elements 9 inside or at the surface of the casing 6 assure the temperature that the compound of the formula (II) and XOH, are at a temperature of above the melting point of XOH, particularly between 320°C and 450°C, more particularly between 330°C and 450°C, even more particularly between 360°C and 450°C, preferably between 360°C and 420°C, more preferably between 380°C and 400°C, so that the reaction can occur and the compound of the formula (I) is formed in the extruder, which leaves the extruder through the outlet of the extruder 3. It is preferred that the reaction mixture is heated in such a way that the temperature gradient of reaction mixture of compound of the formula (II) and XOH is obtained so that said reaction mixture in the section near the inlet 2,4 are at lower temperature than the reaction mixture in the section near the outlet 3. It is preferred that the extruder provides at least one degassing outlet 10 to enable gas to escape from the cavity to reduce the pressure built-up by gas formed during the reaction. The degassing outlet preferably has a pressure control valve 1 1 .

[0114] Figure 3 shows in a schematic manner an embodiment of the process of the invention with a first extruder 1 a, in which in step aO) the compound of the formula (II), particularly of formula (I l-A), is neutralized and with a second extruder 1 b, in which reaction step b) is performed to yield the compound of the formula(l).

[0115] The compound of the formula (II), particularly of the formula (I l-A), is introduced into the first extruder 1 a by the inlet 2a and the base XOH, particularly NaOH, preferably in form of pearls or pellets of several millimeters, as commercially available, is introduced into the first extruder 1 a by the inlet 4. In the first extruder 1 a the neutralization reaction is performed at a temperature of between 100°C and 200°C, particularly between 100°C and 180°C, more particularly between 100°C and 150°C, preferably between 1 10°C and 130°C, to form the compound of the formula (I l-B) which leaves the first extruder 1 a through the outlet 3a of the first extruder 1 a. The compound of the formula (I l-B) is transferred from the outlet 3a of the first extruder to the inlet of the second extruder 1 b by a connection means 12, such as for example a tube, which is closed towards the environment.

[0116] The base the base XOH, particularly NaOH, preferably as a melt, is introduced by the inlet 4 into the second extruder 1 b, where the reaction of step b) occurs at a temperature of above the melting point of XOH, particularly between 320°C and 450°C, more particularly between 330°C and 450°C, even more particularly between 360°C and 450°C, preferably between 360°C and 420°C, more preferably between 380°C and 400°C, to yield the compound of the formula (I), and compound of the formula (I) is leaving the second extruder through the outlet 3b of the second extruder. Furthermore, figure 3 shows that the compound of formula (I) is transferred from the outlet 3b of the second extruder to a vessel with water 13 by a connection means 12, such as for example a tube, which is closed towards the environment. The compound of the formula (I) can be isolated from the vessel with water 13. To enable escaping gas, particular water vapor from the first extruder 1 a and the second extruder 1 b the extruders comprise in the shown figure 3 a degassing outlet 10, which comprises preferably a pressure control valve.

[0117] Figure 4 shows in a schematic manner in a cross-sectional view more details of the preferred embodiment with a first extruder 1 a and second extruder 1 b. The extruder 1 a comprises a cavity 5 surrounded by a casing 6. Inside the cavity 5, a screw 7 of the first extruder is localized. The compound of the formula (ll-A), particularly (II-A2), respectively XOH, is introduced, preferably by means of a pump 15, through the inlet 2a and the inlet 4 for KOH and / or NaOH into the cavity 5 of the first extruder. It is preferred that XOH, preferably particularly NaOH, is introduced in form of pearls or pellets of several millimeters, as commercially available, to the first extruder 1 . The screw 7 is rotated (indicated by arrow A) by a motor 8 around its longitudinal axis. By the rotating action of the screw 7 the compound of formula (ll-A) and XOH are thoroughly mixed and transported along the axis from the entry to the outlet of the extruder (indicated by the arrow B). The heating elements 9 inside or at the surface of the casing 6 assure the temperature that the compound of the formula (ll-A) and XOH, are at a temperature of between 100°C and 200°C, particularly between 100°C and 180°C, more particularly between 100°C and 150°C, preferably between 1 10°C and 130°C, to perform the neutralization step aO), i.e. to form the compound of the formula (ll-B).

[0118] It is preferred that the mixture of compound of the formula (ll-A) and XOH is heated in such a way that the temperature gradient is obtained so that said mixture in the section near the inlets 2a, 4 are at lower temperature than the mixture in the section near the outlet 3a. The compound of the formula (I l-B) leaves the first extruder 1 a through the outlet 3a of the first extruder and transferred to the inlet 2b of the second extruder 1 b by a connection means 12, such as for example a tube, which is closed towards the environment. In the present figure shows that this transport is supported by a pump 15.

[0119] The second extruder 1 b comprises a cavity 5 surrounded by a casing 6. Inside the cavity 5, a screw 7 of the second extruder is localized. The compound of the formula (I l-B), respectively XOH, is introduced, preferably by means of a pump 15, through the inlet 2b and the inlet 4 for KOH and / or NaOH into the cavity 5 of the second extruder. It is preferred that XOH, preferably particularly NaOH, is introduced as a melt to the second extruder 1 . The screw 7 is rotated (indicated by arrow A) by a motor 8 around its longitudinal axis. By the rotating action of the screw 7 the compound of formula (I l-B) and XOH are thoroughly mixed and transported along the axis from the entry to the outlet of the extruder (indicated by the arrow B). The heating elements 9 inside or at the surface of the casing 6 assure the temperature that the compound of the formula (I l-B) and XOH, are at a temperature of above the melting point of XOH, particularly between 320°C and 450°C, more particularly between 330°C and 450°C, even more particularly between 360°C and 450°C, preferably between 360°C and 420°C, more preferably between 380°C and 400°C, to perform the reaction step b) as to yield the compound of the formula (I).

[0120] It is preferred that the mixture of compound of the formula (I l-B) and XOH is heated in such a way that the temperature gradient is obtained so that said mixture in the section near the inlets 3a, 4 are at lower temperature than the mixture in the section near the outlet 3b.

[0121] The compound of the formula (I) leaves the second extruder 1 b through the outlet 3b of the second extruder and transferred to vessel 13 with water by a connection means 12, such as for example a tube, which is closed towards the environment. It is preferred that all the connection means 12 and pumps 15 of this embodiment are heated to avoid cooling and solidifying substances inside the connection means. In the present figure shows that this transport is supported by a pump 15. The adding of compound the formula (I) to the water in the vessel 13 is preferably made by stirring using a stirring means 14, such as for example a paddle stirrer. By adding the molten mixture of compound of the formula (I) and residual XOH to the water in the vessel 13 the compound of the formula (I) is coolded down to temperature of less than 100°C, particularly less than 60°C, preferable less than 40°C. By this action the compound of the formula (I) forms solid particles which (not shown in figure 4) whereas other reaction production remain is solution. Therefore, the solid particles of compound of the formula (I) can be easily separated (not shown in figure 4), for example by filtering.

[0122] To enable escaping gas, particular water vapor from the first extruder 1 a and the second extruder 1 b the extruders comprise in the shown figure 4 a degassing outlet 10, which comprises preferably a pressure control valve 11 .

[0123] List of reference signs

[0124] 1 extruder 6 casing

[0125] 1 a first extruder 7 screw of the extruder

[0126] 1 b second extruder 8 motor for rotation of screw 7

[0127] 2 inlet of the extruder 9 heating element

[0128] 2a inlet of the first extruder 1 a 10 degassing outlet

[0129] 2b inlet of the second extruder 1 b 1 1 pressure control valve

[0130] 3 outlet of the extruder 12 connection means

[0131] 3a outlet of the first extruder 1 a 13 vessel with water

[0132] 3b outlet of the second first extruder 1 b 14 stirring means

[0133] 4 inlet for KOH and / or NaOH 15 pump

[0134] 5 cavity

[0135] Examples

[0136] The present invention is further illustrated by the following experiments.

[0137] For the following experiments a lab extruder is used (corresponding to figure 2 (except feeding as a pre-mixture, see below).

[0138] The extruder uses three screws (Length (L) = 2504 mm, outer diameter (D) = 52 mm, L / D s = 48, screw speed (A / ) = as given in table 1 ) which are arranged in line in parallel. A pre-mixture of solid sodium hydroxide and solid sodium 2,5-dimethylbenzenesulfonate (40 / 60 (wt. / wt.)) was introduced by means of a screw pump from a closed funnel at the inlet of the triple screw extruder in a feed rate (Q) as given in table 1 . The barrel of the extruder was heating by 12 individual heating element (210 mm) located along the extruder. Each element was individually heated so that a specific temperature (°C) was obtained to get a temperature gradient from the inlet (left) to the outlet (right):

[0139] In the first zone, the neutralization (step aO) is performed and in the latter zones the melting and reaction (step b) is performed. In the last third of the extruder, a degassing outlet with a pressure control valve is provided.

[0140] Different feed rates leading to different residence time (fr) have been tested. The conversion (C) to sodium 2,5-dimethylphenolate (sodium p-xylenolate) has been determined by analysing the reaction product leaving the extruder at the outlet of the extruder by GCMS and HPLC.

[0141] Table i . examples

Claims

Claims1 . A process for the manufacture of a compound of the formula (I)from a compound of the formula (II)comprising the steps a) providing the compound of the formula (II) b) melting and reacting the compound of the formula (II) with XOH in an extruder (1 ) at a temperature of above the melting point of XOH, particularly between 320°C and 450°C, more particularly between 330°C and 450°C, even more particularly between 360°C and 450°C, preferably between 360°C and 420°C, more preferably between 380°C and 400°C, to yield the compound of the formula (I); characterized in that R is either H or CH3 and Y is SO3H or SOs X+or Cl and X is either Na or K, preferably Na.

2. The process according to claim 1 , characterized in that R = CH3.

3. The process according to claim 1 or 2, characterized in that Y = SO3'X+, particularly SO3'Na+.

4. The process according to claim 3, characterized in that the compound of formula (II) is compound of the formula (I l-B) which is prepared by step aO) aO) neutralizing a compound of the formula (I l-A) with XOH in an extruder at a temperature of between 100°C and 200°C, particularly between 100°C and 180°C, more particularly between 100°C and 150°C, preferably between 110°C and 130°C, to form the compound of the formula (I l-B)5. The process according to claim 4 characterized in that the step of neutralizing aO) is performed in a first extruder (1 a) and step b) of melt reaction is performed in a second extruder (1 b) and that the compound of the formula (II) is transferred from the outlet (3a) of first extruder (1 a) to the inlet (2b) of the second extruder (1 b).

6. The process according to any of the preceding claims 4 or 5 characterized in that step aO) of neutralizing the compound of the formula (II) with sodium hydroxide and / or potassium hydroxide is performed in the presence of a molar excess of XOH, so that the molar ratio of XOH to the compound of the formula (II) is > 1 , particularly between 1 and 2, preferably between 1 and1 .5, more preferably between 1 and 1 .25.

7. The process according to any of the preceding claims 4 to 6 characterized in that the transfer of material between the first extruder (1 a) and the second extruder (1 b) is performed by a connection means (12) which is closed towards the environment.

8. The process according to any of the preceding claims 4 to 7, characterized in that the compound of the formula (I l-A) is obtained by the reaction of the compound of the formula (III) and sulfuric acid (H2SO4)whereinR is either H or CH3, preferably CH3.

9. The process according to any of the preceding claims characterized in that step b) of melting and reacting the compound of the formula (II) with XOH is performed in the presence of a molar excess of XOH, so that the molar ratio of XOH and / or to then compound of the formula (II) is > 2, particularly between 2 and 4, preferably between 2 and 3, more preferably between 2 and 2.5.

10. The process according to any of the preceding claims characterized in that the temperature of the material in the region of the inlet (2) of the extruder (1 ) is lower than in the region of the outlet (3) of the extruder (1 ).1 1 . The process according to any of the preceding claims characterized in that the extruder (1 ) comprises at least one degassing outlet (10).

12. The process according to any of the preceding claims characterized in that XOH is transferred to the extruder in form of solid XOH or in form of a melt of XOH.

13. The process according to any of the preceding claims characterized in that the process is a continuous process.

14. The process according to any of the preceding claims characterized in that the extruder (1 ) is a twin or triple screw extruder.

15. The process according to any of the preceding claims characterized in that the compound of the formula (I), particularly together with excess of molten XOH, is transferred after the step b) to a vessel (13) comprising water, particularly into an aqueous sulphite solution, preferably an aqueous solution of Na2SC>3.

16. A process of manufacturing of a compound of the formula (IV)characterized in that the process comprises the step i) preparing a compound of the formula (I) by a process according to any of the preceding claims 1 -15,followed by a step c) acidifying the compound of formula (I) with an acid to yield the compound of the formula (IV), whereinR is either H or CH3, preferably CH3.

17. Use of an extruder (1 ) in the manufacturing of the compound of the formulawhereinR is either H or CH3, preferably CH3 and X is either Na or K, preferably Na.

18. Extruder (1 ) for the manufacturing of the compound of the formula (I) comprising at least -a casing (6) -a cavity (5) inside the casing (6)-a extruder screw (7) inside the cavity (5)-an inlet (2) for the compound of the formula (II)-an outlet (3) for the compound of the formula (I)-a mixture of XOH and the compound of the formula (II) inside the cavity (5);characterized in that R is either H or CH3 and Y is SO3H or SOs'X+or Cl and X is either Na or K, preferably Na.

Images