Method for reducing aldehydes in polyether polyol modified silicone oil and used catalyst

Abstract

The invention belongs to the technical field of organic silicon fine chemical engineering, and particularly provides a preparation method of a FeNi-Mo-coated BNC catalyst, which comprises the following steps: dissolving ferric chloride, nickel chloride and ammonium molybdate in a mixed solvent composed of alcohols and water, and then adding phenylboronic acid and dicyandiamide to form a complexing precursor solution; then preparing a nanofiber membrane through electrostatic spinning, and then carrying out multi-stage pyrolysis and doping, pore regulation and surface activation to obtain the Fe-Ni-Mo-coated BNC catalyst. The invention also provides a method for reducing aldehydes in the polyether polyol modified silicone oil, the FeNi-Mo-coated BNC catalyst is selected, and the method comprises the steps of raw material pretreatment, hydrosilylation reaction, multi-stage adsorption purification and stabilization treatment to obtain the polyether polyol modified silicone oil of which the total content of aldehydes is less than 20 ppm.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine silicone chemicals, and specifically relates to a method for reducing aldehyde substances in polyether polyol-modified silicone oil and a catalyst used therefor. Background Art

[0002] Polyether polyol-modified silicone oil has important application value in the fields of daily chemicals, textiles, and coatings due to its unique surface activity and compatibility. However, the problem of aldehyde residues generally exists in the existing production process (typical content 200 - 500 ppm), which severely restricts the application of the product in the high-end market. The existing technology fails to effectively solve the problem of continuous generation of aldehyde substances in a humid and hot environment, resulting in poor long-term stability of the product and prominent safety risks.

[0003] Ultimately, the generation of aldehyde substances runs through the whole process of raw material storage, synthesis reaction, and post-treatment; specifically as follows:

[0004] Firstly, the residual transition metal ions (such as Fe 3+ / Cu 2+ ) in the raw material allyl alcohol polyether will catalyze the autoxidation chain reaction of the intramolecular unsaturated double bond, and through the cleavage of the hydroperoxide intermediate, straight-chain aldehydes with C3 - C6 (such as the monthly average production amount of acrolein disclosed in CN109876512A reaches 80 ppm) are generated;

[0005] Secondly, in the platinum-catalyzed hydrosilylation process, the activation efficiency of the traditional platinum-based catalyst (such as Pt / C) for the Si - H bond is limited, resulting in a residual rate of Si - H bonds in the reaction system > 5% (such as the residual rate in the process of CN110591122B reaches 6.8%). The unreacted Si - H bonds hydrolyze with water vapor during subsequent storage to generate ≡Si - OH active sites, inducing the homolytic cleavage of the C - O bond of the adjacent polyether segment, and continuously releasing aldehyde substances through the formate intermediate pathway (the aldehyde content in the product of the process of US20180273622A1 increases by more than 30% in a humid and hot environment);

[0006] Furthermore, the traditional aldehyde removal technology has systematic defects - vacuum distillation method results in the residue of high-boiling aldehydes due to the boiling point difference of aldehyde substances (the removal rate of formaldehyde by activated carbon adsorption in JP2019152024A is less than 40%), chemical treatment methods such as the addition of bisulfite are difficult to eliminate α,β-unsaturated aldehydes (the residual amount of acrolein in KR1020180034567B is > 50 ppm), while high-temperature physical purification means instead trigger the pyrolysis of the polyether chain to generate new aldehyde pollutants (the increment of propionaldehyde in the nitrogen purge process of CN110591122B reaches 28 ppm).

[0007] The prior art is mostly limited to local improvements in a single link and fails to construct a collaborative control system starting from multiple generation mechanisms such as the preparation of new catalysts, oxidative chain reactions, hydrolysis side reactions, and thermal degradation, resulting in poor long-term stability of products and prominent safety risks. Therefore, developing a multi-stage collaborative aldehyde removal process that combines source inhibition, deep capture, and stabilization treatment has become an urgent need in the industry.

[0008] In summary, the technical problems existing in the prior art are:

[0009] The platinum-based catalyst for the common hydrosilylation reaction is prone to poisoning on the surface, with a high residual rate of Si-H bonds. The formation path of aldehydes is complex (oxidation, hydrolysis, thermal degradation), the efficiency of single treatment technology is low (such as the adsorption rate of activated carbon <40%, and α,β-unsaturated aldehydes remain after chemical treatment), and there is a lack of a full-chain collaborative control system, etc., resulting in limited high-end applications. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a method for reducing aldehyde substances in polyether polyol modified silicone oil and the catalyst used.

[0011] To solve the above technical problems, the present invention provides a preparation method of a FeNi-Mo@BNC catalyst, including the following steps:

[0012] Dissolve ferric chloride, nickel chloride, and ammonium molybdate in a mixed solvent composed of alcohols and water, and then add phenylboronic acid and dicyandiamide to form a complex precursor solution;

[0013] The complex precursor solution is prepared into a nanofiber membrane by electrospinning, and then through multi-stage pyrolysis and doping, pore regulation and surface activation, a Fe-Ni-Mo@BNC catalyst is obtained.

[0014] Note: B represents boron; N represents nitrogen; C represents doping.

[0015] As an improvement to the preparation method of the FeNi-Mo@BNC catalyst of the present invention, the following steps are included:

[0016] ①. Preparation of the precursor solution:

[0017] According to the molar ratio of ferric chloride: nickel chloride: ammonium molybdate = 1: 0.24 - 0.35: 0.03 - 0.05 (preferably 1: 0.24 - 0.33: 0.035 - 0.045), dissolve the metal salts composed of ferric chloride, nickel chloride, and ammonium molybdate in a mixed solvent composed of alcohols and water, and then add an aqueous solution of phenylboronic acid as a complexing agent and an aqueous solution of dicyandiamide, and stir evenly (stir evenly at 60 ± 10 °C) to form a complex precursor solution (a homogeneous metal complex precursor solution);

[0018] The molar ratio of ferric chloride to phenylboronic acid is 1:(1.5±0.1), and the molar ratio of ferric chloride to dicyandiamide is 1:(2.5±0.1);

[0019] ②. Preparation of composite fibers by electrospinning:

[0020] Mix the complex precursor solution obtained in step ① with polyacrylonitrile (PAN, Mw = 150,000), and stir magnetically for 24±2 hours to form a homogeneous spinning solution; the mass ratio of polyacrylonitrile to the complex precursor solution is (2±0.2):1;

[0021] Prepare the homogeneous spinning solution into a nanofiber membrane (fiber diameter is 80±10nm), and then dry it;

[0022] ③. Multi-stage pyrolysis and doping:

[0023] Place the dried fiber membrane obtained in step ② in a tube furnace, and carry out reactions in the following stages in sequence:

[0024] The first stage (pyrolysis and pre-carbonization): Heat up to 400±20°C, introduce N2, and keep the temperature for reaction for 1±0.1 hour;

[0025] The second stage (gas-phase doping): Stop introducing N2, after heating up to 850±20°C, switch to introducing a mixture of NH3 / BCl3, and the volume flow ratio of NH3:BCl3 is (5±0.5):1; keep the temperature for reaction for 2±0.1 hour;

[0026] The third stage (reductive annealing): Stop introducing the NH3 / BCl3 mixture, after heating up to 900±20°C, switch to introducing a mixture of Ar / H2, so as to replace all the gases in the tube furnace with Ar / H2; then, in the atmosphere of Ar / H2, keep the temperature for annealing reaction for 30±5 minutes, and then cool down to obtain the Fe-Ni-Mo@BNC crude product; the volume flow ratio of Ar:H2 is 94 - 96:4 - 6 (preferably 95:5);

[0027] Note:

[0028] The first stage (pyrolysis and pre-carbonization): Formation of carbon skeleton and generation of metal oxides;

[0029] The second stage (gas-phase doping): B / N co-doping to construct a B-N-C active interface;

[0030] The third stage (reductive annealing): Generation and dispersion of metal nanoparticles;

[0031] ④. Pore regulation and surface activation

[0032] Immerse the Fe-Ni-Mo@BNC crude product in a NaOH solution with a concentration of 0.08 - 0.12 mol / L (preferably 0.1 mol / L), and ultrasonically treat it for 2 ± 0.5 hours (at room temperature, with a power of 100 ± 20 W), thereby achieving pore regulation (forming a gradient pore structure);

[0033] Then wash it with a HNO3 solution with a concentration of 0.04 - 0.06 mol / L (preferably 0.05 mol / L), and finally place it in a tube furnace heated to 300 ± 20 °C, and introduce an Ar / H2 mixed gas, with the volume flow ratio of Ar:H2 = 94 - 96:4 - 6 (preferably 95:5), and keep it warm for the reduction reaction for 1 ± 0.1 hours; to obtain the active catalyst FeNi-Mo@BNC.

[0034] Note: The material-liquid ratio of the Fe-Ni-Mo@BNC crude product to the NaOH solution is 1 g / (10 ± 2) ml.

[0035] As a further improvement to the preparation method of the FeNi-Mo@BNC catalyst of the present invention, in the step ①:

[0036] For every 20 - 30 mmol of ferric chloride, 120 - 140 mL of the mixed solvent is used;

[0037] In the mixed solvent, the volume ratio of alcohol to water = (4 ± 0.2):1;

[0038] The concentration of the phenylboric acid aqueous solution is 0.25 - 0.35 mol / L (preferably 0.3 mol / L), and the concentration of the dicyandiamide aqueous solution is 0.45 - 0.55 mol / L (preferably 0.5 mol / L).

[0039] The ferric chloride is FeCl3·6H2O, the nickel chloride is NiCl2·6H2O, and the ammonium molybdate is (NH4)4Mo4O 24 ·4H2O.

[0040] As a further improvement to the preparation method of the FeNi-Mo@BNC catalyst of the present invention, in the step ①:

[0041] The alcohol in the mixed solvent is ethylene glycol.

[0042] As a further improvement to the preparation method of the FeNi-Mo@BNC catalyst of the present invention, in the step ②:

[0043] Prepare a nanofiber membrane through an electrospinning machine, and the electrospinning machine parameters: voltage 18 ± 1 kV, propulsion rate 1.2 ± 0.1 mL / h, receiving distance 15 ± 1 cm;

[0044] The obtained fiber membrane was dried in vacuum at 80 ± 10 °C for 12 ± 1 hour, and finally a dried fiber membrane (with solvent residue < 0.5%) was obtained.

[0045] Note: By using the method of the present invention, the fiber diameter of the nanofiber membrane can be controlled within 80 ± 10 nm, thereby ensuring the specific surface area and activity of the obtained catalyst; the fiber diameter can be detected by conventional SEM (scanning electron microscope).

[0046] As an improvement of the preparation method of the FeNi-Mo@BNC catalyst of the present invention,

[0047] In step ③:

[0048] The first stage: Heat up to 400 ± 20 °C at a rate of (3 ± 0.5) °C / min, and the N2 flow rate per minute is 0.8 - 1.2% (preferably 1%) of the volume of the tubular furnace;

[0049] The second stage: Heat up to 850 ± 20 °C at a rate of (5 ± 0.5) °C / min, and the flow rate of the NH3 / BCl3 mixed gas per minute is 1.8 - 2.2% (preferably 2%) of the volume of the tubular furnace;

[0050] In step ④: The flow rate of Ar / H2 per minute is 4 - 6% (preferably 5%) of the volume of the tubular furnace;

[0051] That is, in step ③: The volume of the tubular furnace is 10 L (about 350 - 450 g of the dried fiber membrane is placed inside), the preferred N2 flow rate in the first stage is 100 mL / min, and the preferred flow rate of the NH3 / BCl3 mixed gas in the second stage is 200 mL / min;

[0052] In step ④: The volume of the tubular furnace is 1 L (about 50 - 100 g of the coarsened product after pickling is placed inside), and the preferred flow rate is 50 mL / min.

[0053] The present invention also simultaneously provides an FeNi-Mo@BNC catalyst prepared by any of the above methods: The metal loadings of the FeNi-Mo@BNC catalyst are Fe 4.0 - 4.5 wt%, Ni 1.0 - 1.5 wt%, Mo 0.4 - 0.6 wt%, and the BET specific surface area > 400 m 2 / g.

[0054] In the present invention, it can be achieved that in FeNi-Mo@BNC, the B / N atomic ratio is 1:1.2, as verified by XPS.

[0055] The present invention also simultaneously provides a method for reducing aldehyde substances in polyether polyol modified silicone oil (that is, a method for inhibiting the formation and multi-stage synergistic removal of aldehyde substances in polyether polyol modified silicone oil): Select an FeNi-Mo@BNC catalyst, and the method includes the following steps:

[0056] 1), Raw material pretreatment:

[0057] Ethylenediaminetetramethylenephosphonic acid (EDTMP) as a complexing agent and diatomaceous earth as an adsorption carrier are added to allyl alcohol polyether (molecular weight 750), and the mixture is stirred and reacted for 2 hours (300 ± 50 rpm) under the protection of an inert gas (nitrogen), and then centrifuged / filtered to obtain pretreated allyl alcohol polyether;

[0058] The addition amount of the ethylenediaminetetramethylenephosphonic acid (EDTMP) is 0.1% - 0.5% (preferably 0.3% - 0.5%) of the mass of allyl alcohol polyether, and the addition amount of diatomaceous earth is 1% - 3% (preferably 2% - 3%) of the mass of allyl alcohol polyether;

[0059] Note: The purpose of this step 1) is to remove Fe 3+ / Cu 2+ impurities; the sum of the residual amounts of Fe 3+ and Cu 2+ in the obtained pretreated allyl alcohol polyether is < 2 ppm;

[0060] 2), Hydrosilylation reaction:

[0061] All of the pretreated allyl alcohol polyether obtained in step 1) and hydrogen-containing silicone oil are subjected to the following two-stage temperature-controlled reaction under the action of an FeNi-Mo@BNC catalyst and under the protection of a slightly positive pressure (0.05 ± 0.01 Mpa) inert gas (nitrogen):

[0062] The first stage is a reaction at 75 - 90 °C for 2 - 5 hours (preferably a reaction at 85 ± 5 °C for 3 ± 0.5 h),

[0063] The second stage is to cool down to 60 - 70 °C and react for 5 ± 0.5 hours; a crude product of polyether polyol modified silicone oil is obtained;

[0064] The molar ratio of pretreated allyl alcohol polyether to hydrogen-containing silicone oil is 1:0.92 - 1.25 (preferably 1:0.95 - 1.2);

[0065] The total weight of the allyl alcohol polyether and hydrogen-containing silicone oil in step 1) is named the total weight of raw materials;

[0066] The dosage of the FeNi-Mo@BNC catalyst is 0.05% - 0.15% (preferably 0.08% - 0.12%) of the total weight of raw materials;

[0067] The Si-H bond content of the hydrogen-containing silicone oil is 1.0 - 2.5 mol / kg (preferably 1.2 mol / kg);

[0068] Note: The residual rate of the Si-H bond after the reaction is < 3%;

[0069] 3), Multi-stage adsorption purification:

[0070] Add a composite adsorbent to the crude polyether polyol-modified silicone oil obtained from all of Step 2), and stir at 50 ± 10 °C under vacuum conditions (vacuum degree -0.08 ± 0.01 MPa) for 4 ± 0.5 hours, then filter to obtain purified polyether-modified silicone oil;

[0071] The composite adsorbent is composed of activated carbon, β-cyclodextrin, and aminated mesoporous SiO2 in a weight ratio of 1 - 5:1:1 - 5 (preferably 3 - 5:1:2 - 5);

[0072] The composite adsorbent accounts for 1% - 10% of the total weight of the raw materials (preferably 5% - 10%);

[0073] 4), Stabilization treatment:

[0074] Add triethanolamine (as a Si-OH blocking agent) and a hindered phenol antioxidant to the purified polyether-modified silicone oil obtained from all of Step 3), vacuum degas and then filter to obtain polyether polyol-modified silicone oil (polyether polyol-modified silicone oil with a total aldehyde content < 20 ppm);

[0075] Triethanolamine: total weight of raw materials = 0.5% - 2% (preferably 1% - 2%) by mass ratio;

[0076] Hindered phenol antioxidant: total weight of raw materials = 0.1% - 1% (preferably 0.5% - 1%) by mass ratio.

[0077] As an improvement to the method for reducing aldehyde substances in polyether polyol-modified silicone oil according to the present invention:

[0078] The hindered phenol antioxidant in Step 4) is Irganox 1010.

[0079] As a further improvement to the method for reducing aldehyde substances in polyether polyol-modified silicone oil according to the present invention:

[0080] In Step 4): The vacuum degassing is: vacuum degassing at 60 ± 10 °C for 1 hour; the filtration is through a 0.45 μm filter membrane.

[0081] The present invention proposes a multi-stage cooperative aldehyde removal method, which realizes the full-chain control from source inhibition to deep removal through a multi-stage cooperative process.

[0082] The present invention particularly aims at polyether-modified silicone oil prepared from allyl alcohol polyether and hydrogen-containing silicone oil, and realizes the source inhibition and deep removal of aldehyde impurities through a multi-stage cooperative process including catalyst design and preparation, raw material purification, reaction control, composite adsorption, and stabilization treatment.

[0083] In the present invention:

[0084] 1. The innovative design of the FeNi-Mo@BNC catalyst is beneficial to reducing the residual of Si-H bonds in the hydrosilylation reaction.

[0085] Specifically:

[0086] The introduction of Mo can shift the d-band center of Fe upward by 0.3 eV, enhance the polarization ability of the Si-H bond, and form a ternary alloy electronic effect.

[0087] XPS analysis shows that the B / N co-doped layer preferentially adsorbs the hydrosilyl group, while the sulfur / nitrogen-containing compound is restricted outside the carbon shell due to steric hindrance, thus improving the performance of the catalyst.

[0088] That is, the FeNi-Mo@BNC catalyst of the present invention realizes the unity of high activity and anti-poisoning performance.

[0089] 2. Raw material pretreatment: The combined use of a phosphonic acid-based complexing agent - ethylenediaminetetramethylenephosphonic acid (such as EDTMP) and diatomite adsorption can remove Fe 3+ / Cu 2+ impurities (residual amount < 2 ppm) and inhibit the formation of aldehydes in the auto-oxidation path.

[0090] 3. Synthesis reaction control: In the hydrosilylation stage, stepwise temperature control and slightly positive pressure protection with inert gas are adopted. Using the FeNi-Mo@BNC catalyst, the residual rate of Si-H bonds is reduced to < 3%, avoiding the generation of aldehydes by subsequent hydrolysis.

[0091] 4. Multi-stage adsorption purification: A composite adsorbent combination (activated carbon-β-cyclodextrin-aminated mesoporous SiO2) is used to adsorb C3-C6 aldehydes in a gradient manner (total removal rate ≥ 95%).

[0092] 5. Stabilization treatment: Adding a nitrogen-containing blocking agent triethanolamine and a hindered phenolic antioxidant (Irganox 1010) to block the path of aldehyde generation by hydrolysis and thermal degradation.

[0093] In summary, the present invention belongs to a method for inhibiting the formation of aldehyde substances in polyether polyol modified silicone oil and multi-stage synergistic removal, which is applicable to the fields of high-end daily chemicals, textiles and coatings. In the present invention, multi-stage synergistic kinetics is set: based on the pore distribution and chemical bonding of the adsorbent, gradient capture is realized (activated carbon adsorbs low-boiling aldehydes, β-cyclodextrin encapsulates medium-chain aldehydes, and amino SiO2 chelates high-boiling α,β-unsaturated aldehydes); a stabilization dual mechanism is also set: the synergistic effect of the blocking agent and the antioxidant inhibits the Si-OH active sites and the free radical chain reaction, and the aldehyde increment after damp heat aging is small. Using the method of the present invention, the total content of aldehyde substances in the final product is <20 ppm, and the aldehyde increment is ≤5 ppm after 30 days of damp heat accelerated test at 70 °C and RH 85%. Detailed implementation mode

[0094] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0095] The stirring speed in the present invention is 200-350 rmp.

[0096] Preparation example 1 of catalyst, preparation of FeNi-Mo@BNC catalyst:

[0097] (1) Preparation of precursor solution:

[0098] Dissolve 25.9 mmol of ferric chloride hexahydrate (FeCl3·6H2O, 7.00 g), 7.8 mmol of nickel chloride hexahydrate (NiCl2·6H2O, 1.85 g) and 1 mmol of ammonium molybdate tetrahydrate ((NH4)6Mo7O 24 ·4H2O, 1.28 g) in 129.4 ml of a mixed solvent composed of ethylene glycol / deionized water (ethylene glycol / deionized water = 4:1 volume ratio). Subsequently, add an aqueous solution of phenylboronic acid containing 39 mmol of phenylboronic acid (0.3 mol / L) and an aqueous solution of dicyandiamide containing 65 mmol of dicyandiamide (0.5 mol / L) as complexing agents, and stir evenly at 60 °C to form a precursor solution (a homogeneous metal complex precursor solution).

[0099] (2) Preparation of composite fibers by electrospinning:

[0100] Take 155 g of the precursor solution obtained in step (1) and mix it with 310 g of polyacrylonitrile (PAN, Mw = 150,000), and stir magnetically for 24 hours to form a homogeneous spinning solution.

[0101] Then, use an electrospinning machine to prepare the homogeneous spinning solution into a nanofiber membrane, and set the parameters of the electrospinning machine as: voltage 18 kV, propulsion rate 1.2 mL / h, and receiving distance 15 cm.

[0102] The fiber diameter in the obtained fiber membrane is about 80 nm; the fiber membrane is vacuum-dried at 80 °C for 12 hours to finally obtain a dried fiber membrane (ethylene glycol residue < 0.5%).

[0103] Note: The fiber diameter can be detected by conventional SEM (scanning electron microscope).

[0104] (3) Multi-stage pyrolysis and doping:

[0105] Place the dried fiber membrane (about 386 g) obtained in step (2) in a tubular furnace (volume 10 L), and conduct reactions in the following stages in sequence:

[0106] The first stage (pyrolysis and pre-carbonization): Heat up to 400 °C at a rate of 3 °C / min, introduce N2 with a flow rate of 100 mL / min, keep the temperature for 1 hour, and name the obtained product as the intermediate, obtaining about 200 g of the intermediate; the tail gas generated by the reaction is discharged from the tubular furnace in real time;

[0107] The second stage (gas-phase doping): Stop introducing N2, heat up to 850 °C at a rate of 5 °C / min, switch to introducing a mixed gas of NH3 / BCl3 (volume flow ratio of NH3:BCl3 = 5:1, total flow rate 200 mL / min), and keep the temperature for 2 hours; the tail gas generated by the reaction is discharged from the tubular furnace in real time;

[0108] The third stage (reductive annealing): Stop introducing the mixed gas of NH3 / BCl3, quickly heat up to 900 °C (heating rate 15 °C / min), replace all the gas in the tubular furnace with Ar / H2 (Ar:H 2＝ volume ratio of 95:5), and then anneal at 900 °C in an Ar / H2 atmosphere for 30 minutes. After cooling, obtain about 72 g of the Fe-Ni-Mo@BNC crude product;

[0109] Verified by XPS, due to the gas-phase doping in the second stage, in the obtained Fe-Ni-Mo@BNC crude product, the B / N atomic ratio is 1:1.2.

[0110] (4) Pore regulation and surface activation

[0111] According to the dosage ratio of Fe-Ni-Mo@BNC crude product:NaOH solution = 1 g / 10 ml, immerse the Fe-Ni-Mo@BNC crude product in 0.1 mol / L NaOH solution and ultrasonically treat for 2 hours (power 100 W, frequency 20 kHz) to form a gradient pore structure (measured by BET method: specific surface area increased to 420 m 2 / g).

[0112] Then wash with 0.05 mol / L HNO3 solution 3 times to obtain the pickled crude product;

[0113] The crude product after pickling was placed in a tube furnace (volume: 1 L) heated to 300 °C, and an Ar / H₂ mixed gas (total flow rate: 50 mL / min, Ar:H₂ = 95:5) was introduced. It was kept at 300 °C for reduction for 1 hour, and finally the active catalyst Fe-Ni-Mo@BNC was obtained. The metal loadings of this catalyst were determined by ICP: Fe 4.2 wt%, Ni 1.3 wt%, Mo 0.5 wt%.

[0114] Catalyst Preparation Example 2: The amounts of ferric chloride hexahydrate, nickel chloride hexahydrate, and ammonium molybdate tetrahydrate in step (1) of Catalyst Preparation Example 1 were changed to 24.7 mmol of ferric chloride hexahydrate, 6 mmol of nickel chloride hexahydrate, and 0.8 mmol of ammonium molybdate tetrahydrate, respectively; the rest was the same as in Catalyst Preparation Example 1.

[0115] The metal loadings of the catalyst were determined by ICP: Fe 4.0 wt%, Ni 1.0 wt%, Mo 0.4 wt%.

[0116] Catalyst Preparation Example 3: The amounts of ferric chloride hexahydrate, nickel chloride hexahydrate, and ammonium molybdate tetrahydrate in step (1) of Catalyst Preparation Example 1 were changed to 27.8 mmol of ferric chloride hexahydrate, 9 mmol of nickel chloride hexahydrate, and 1.2 mmol of ammonium molybdate tetrahydrate, respectively; the rest was the same as in Catalyst Preparation Example 1.

[0117] The metal loadings of the catalyst were determined by ICP: Fe 4.5 wt%, Ni 1.5 wt%, Mo 0.6 wt%.

[0118] Catalyst Comparative Example 1: The use of ammonium molybdate tetrahydrate in step (1) of Catalyst Preparation Example 1 was cancelled; and the amount of nickel chloride hexahydrate was correspondingly increased, that is, the amount of nickel chloride hexahydrate was changed from 7.8 mmol to 8.8 mmol; the rest was the same as in Catalyst Preparation Example 1.

[0119] The metal loadings of the catalyst were determined by ICP: Fe 4.2 wt%, Ni 1.5 wt%.

[0120] Catalyst Comparative Example 2: The amount of ammonium molybdate tetrahydrate in step (1) of Catalyst Preparation Example 1 was increased, such that the amount of ammonium molybdate tetrahydrate was changed from 1 mmol to 2 mmol; the rest was the same as in Catalyst Preparation Example 1.

[0121] The metal loadings of the catalyst were determined by ICP: Fe 4.2 wt%, Ni 1.3 wt%, Mo 1 wt%.

[0122] Catalyst Comparative Example 3: In the second stage (gas-phase doping) of step (3) of Catalyst Preparation Example 1, the "NH₃ / BCl₃ mixed gas" was changed to all NH₃, and the rest was the same as in Catalyst Preparation Example 1.

[0123] Catalyst Comparative Example 4: In the second stage (gas-phase doping) of Step (3) of Catalyst Preparation Example 1, change the "NH3 / BCl3 mixed gas" to "NH3:BCl3 = 5:2 flow ratio" from "NH3:BCl3 = 5:1 flow ratio", and the rest is the same as Catalyst Preparation Example 1.

[0124] Catalyst Comparative Example 5: The parameters of the electrospinning machine for "electrospinning to prepare composite fibers" in Step (2) of Catalyst Preparation Example 1 are: voltage 16 kV, feeding rate 1.5 mL / h, and receiving distance 12 cm. Thus, the fiber diameter in the obtained fiber membrane is about 100 nm; the rest is the same as Catalyst Preparation Example 1.

[0125] Catalyst Comparative Example 6: The parameters of the electrospinning machine for "electrospinning to prepare composite fibers" in Step (2) of Catalyst Preparation Example 1 are: voltage 20 kV, feeding rate 0.9 mL / h, and receiving distance 18 cm. Thus, the fiber diameter in the obtained fiber membrane is about 60 nm; the rest is the same as Catalyst Preparation Example 1.

[0126] The molecular weight of the following allyl alcohol polyethers refers to the average molecular weight.

[0127] Example 1:

[0128] In this example, allyl alcohol polyether with a molecular weight of 750 (g / mol) is used as the raw material, and the efficient inhibition and removal of aldehyde substances are realized through a multi-stage collaborative process. The specific steps are as follows:

[0129] 1. Raw material pretreatment:

[0130] Mix 506.3 g (0.675 mol) of allyl alcohol polyether (initial Fe 3+ content 50 ppm) with 1.52 g of EDTMP complexing agent, add 10.13 g of diatomite as an adsorption carrier, and stir at 300 ± 50 rpm for 2 hours under nitrogen protection. After centrifugal separation, remove the filter residue, and the obtained filtrate is the pretreated allyl alcohol polyether. The Fe 3+ residual amount of the pretreated allyl alcohol polyether is reduced to 0.8 ppm. And it satisfies that the sum of the Fe 3+ and Cu 2+ residual amounts is < 2 ppm.

[0131] That is, the weight ratio of EDTMP:allyl alcohol polyether = 0.3%; the weight ratio of diatomite:allyl alcohol polyether = 2%;

[0132] 2. Hydrosilylation reaction:

[0133] About 466.2 g (0.6216 mol) of all the pre-treated allyl alcohol polyether obtained in Step 1 and 493.7 g (0.592 mol, i.e., the Si-H bond content is 1.2 mol / kg) of hydrosilicone oil were put into a reaction kettle (i.e., the molar ratio of pre-treated allyl alcohol polyether to hydrosilicone oil is 1:0.95), and 0.80 g of the FeNi-Mo@BNC catalyst obtained in Preparation Example 1 was added. Under the protection of nitrogen environment with a slightly positive pressure (0.05 Mpa), the following two-stage temperature-controlled reaction was carried out in sequence:

[0134] In the first stage, the reaction was carried out at 85 °C for 3 hours to complete about 80% of the Si-H bond addition;

[0135] In the second stage, the temperature was lowered to 65 °C and the reaction was continued for 5 hours to obtain a crude product of polyether polyol-modified silicone oil, and the residual rate of Si-H bond in the crude product was 1.5% (tested by nuclear magnetic resonance).

[0136] The total weight of the allyl alcohol polyether in Step 1 and the hydrosilicone oil in Step 2 was named the total weight of raw materials; therefore, the FeNi-Mo@BNC catalyst accounted for 0.08% of the total weight of raw materials.

[0137] 3. Multi-stage adsorption purification:

[0138] 50 g of a composite adsorbent was added to the reaction product obtained in Step 2, and the mixture was stirred at 50 °C and a vacuum degree of -0.08 Mpa for 4 hours and then filtered. The filtrate was the purified polyether-modified silicone oil with a number average molecular weight of 12,000 and a molecular weight distribution of 1.15.

[0139] The composite adsorbent was composed of activated carbon:β-cyclodextrin:aminated mesoporous SiO2 (activated carbon:β-CD:SiO2) in a weight ratio of 3:1:2; that is, the composite adsorbent accounted for 5% of the total weight of raw materials.

[0140] The aminated mesoporous SiO2 was aminated mesoporous silica nanoparticles (NH2-MSN) prepared with reference to the publicly disclosed "Synthesis and Formation Mechanism of Aminated Mesoporous Silica Nanoparticles". The specific preparation method was as follows:

[0141] At room temperature, 0.9 g of cetyltrimethylammonium bromide (CTAB) was added to a mixed solution of 1.4 mL of ammonia water, 90 mL of ultrapure water and 70 mL of absolute ethanol. After mechanical stirring for 30 minutes, 0.8 mL of tetraethyl orthosilicate (TEOS) and 0.4 mL of 3-aminopropyltriethoxysilane (APTES) were successively added dropwise to the continuously stirred mixed solution. After reacting for 24 hours, the sample was centrifuged, washed repeatedly with ultrapure water and absolute ethanol, and then dried. The dried product was placed in a mixed solution of 5 mL of hydrochloric acid and 90 mL of absolute methanol and refluxed at 75 °C for 24 h. This reflux operation was repeated 3 times to ensure complete removal of the template agent CTAB. The product obtained by reflux was washed repeatedly with absolute ethanol and dried at 50 °C and then ground (passed through a 200-mesh sieve) to obtain amino-functionalized mesoporous silica nanoparticles.

[0142] 4. Stabilization treatment:

[0143] 10 g of triethanolamine was added to the purified polyether-modified silicone oil obtained in Step 3 as a Si-OH blocking agent, and at the same time, 5 g of the hindered phenol antioxidant Irganox 1010 was introduced. After vacuum degassing at 60 °C for 1 hour, the product was filtered through a 0.45 μm filter membrane to obtain the final product - polyether polyol-modified silicone oil with a total aldehyde content of 12 ppm.

[0144] That is, triethanolamine accounted for 1% of the total weight of the raw materials, and the hindered phenol antioxidant Irganox 1010 accounted for 0.5% of the total weight of the raw materials.

[0145] Verified by the damp heat accelerated test (stored at 70 °C, RH 85% for 30 days), the aldehyde increment was 3 ppm.

[0146] The key data of Example 1 are as described in Table 1-1 below.

[0147] Table 1 Key data table of Example 1

[0148]

[0149] Example 1-2: The catalyst used in Example 1 (prepared in Catalyst Preparation Example 1) was changed as described in Table 1-2 below, and the rest was the same as in Example 1. The comparison of the obtained results is as shown in Table 1-2:

[0150] Table 1-2

[0151]

[0152]

[0153] Example 2: Change "493.7 g (0.592 mol) of hydrogen-containing silicone oil" in Example 1 to "622.13 g (0.746 mol) of hydrogen-containing silicone oil", that is, the molar ratio of allyl alcohol polyether to hydrogen-containing silicone oil after pretreatment is 1:1.2; and appropriately adjust the dosage of the FeNi-Mo@BNC catalyst so that the FeNi-Mo@BNC catalyst accounts for 0.08% of the total weight of the raw materials remains unchanged, and the rest is the same as in Example 1.

[0154] Comparative Example 1: Change "493.7 g (0.592 mol) of hydrogen-containing silicone oil" in Example 1 to "466.18 g (0.559 mol)", that is, the molar ratio of allyl alcohol polyether to hydrogen-containing silicone oil after pretreatment is 1:0.9, and appropriately adjust the dosage of the FeNi-Mo@BNC catalyst so that the FeNi-Mo@BNC catalyst accounts for 0.08% of the total weight of the raw materials remains unchanged, and the rest is the same as in Example 1.

[0155] Example 3: Change the dosage of the EDTMP complexing agent in Example 1 so that the weight ratio of EDTMP to allyl alcohol polyether is 0.5%; the rest of the conditions are the same as in Example 1.

[0156] Comparative Example 2: Change the dosage of the EDTMP complexing agent in Example 1 so that the weight ratio of EDTMP to allyl alcohol polyether is 0.05%; the rest of the conditions are the same as in Example 1.

[0157] Example 4: Change the dosage of diatomaceous earth in Example 1 so that the weight ratio of diatomaceous earth to allyl alcohol polyether is 3%; the rest of the conditions are the same as in Example 1.

[0158] Comparative Example 3: Change the dosage of diatomaceous earth in Example 1 so that the weight ratio of diatomaceous earth to allyl alcohol polyether is 0.5%; the rest of the conditions are the same as in Example 1.

[0159] The comparison of the key data of the above cases is shown in Table 2 below.

[0160] Table 2

[0161]

[0162]

[0163] Example 5: Change the dosage of the FeNi-Mo@BNC catalyst in Example 1 to 1.2 g (that is, the FeNi-Mo@BNC catalyst accounts for 0.12% of the total weight of the raw materials), and the rest of the conditions are the same as in Example 1.

[0164] Comparative Example 4: The dosage of the FeNi-Mo@BNC catalyst in Example 1 is 0.3 g (the FeNi-Mo@BNC catalyst accounts for 0.03% of the total weight of the raw materials), and the rest of the conditions are the same as in Example 1.

[0165] The comparison of the key data of the above cases is shown in Table 3 below.

[0166] Table 3

[0167]

[0168]

[0169] Example 6: Change the compound adsorbent ratio (activated carbon: β-CD: SiO2) in Example 1 to 5:1:3, and the other conditions are the same as those in Example 1.

[0170] Example 7: Change the compound adsorbent ratio (activated carbon: β-CD: SiO2) in Example 1 to 3:1:5, and the other conditions are the same as those in Example 1.

[0171] Comparative Example 5: Change the compound adsorbent ratio (activated carbon: β-CD: SiO2) in Example 1 to 1:1:1, and the other conditions are the same as those in Example 1.

[0172] Example 8: Change the amount of the compound adsorbent in Example 1 to 10 g (i.e., the compound adsorbent accounts for 1% of the total weight of the raw materials), and the ratio of activated carbon: β-CD: SiO2 is still 3:1:2, and the other conditions are the same as those in Example 1.

[0173] Example 9: Change the amount of the compound adsorbent in Example 1 to 100 g (i.e., the compound adsorbent accounts for 10% of the total weight of the raw materials), and the ratio of activated carbon: β-CD: SiO2 is still 3:1:2, and the other conditions are the same as those in Example 1.

[0174] The comparison of the key data of the above cases is shown in Table 4 below.

[0175] Table 4

[0176]

[0177] Example 10: Change the addition amount of triethanolamine in Example 1 to 20 g (i.e., triethanolamine accounts for 2% of the total weight of the raw materials), and the other conditions are the same as those in Example 1.

[0178] Example 11: Change the addition amount of Irganox 1010 in Example 1 to 10 g (i.e., Irganox 1010 accounts for 1% of the total weight of the raw materials), and the other conditions are the same as those in Example 1.

[0179] Comparative Example 6: Change the addition amount of triethanolamine in Example 1 to 5 g (i.e., triethanolamine accounts for 0.5% of the total weight of the raw materials), and the other conditions are the same as those in Example 1.

[0180] Comparative Example 7: The amount of Irganox 1010 added in Example 1 was 1 g (ie, Irganox 1010 accounted for 0.1% of the total weight of the raw materials), and the other conditions were the same as those in Example 1.

[0181] The comparison of key data of the above cases is shown in Table 5.

[0182] Table 5

[0183] Examples and Comparative Examples Example 1 Example 10 Example 11 Comparative Example 6 Comparative Example 7 Triethanolamine addition amount (%) 1 2 1 0.5 1 Irganox 1010 (%) 0.5 0.5 1 0.5 0.1 Residual rate of Si-H bond (%) 1.5 1.7 1.6 2.3 3.8 Final product mass (g) ≈998 ≈998 ≈998 ≈999 ≈998 Molecular weight (Mn) 12,000 12100 12200 11900 11850 PDI 1.15 1.14 1.13 1.17 1.16 Total aldehyde content (ppm) 12 11 10 14 13 Increment of aldehydes in damp heat (ppm) 3 2 1 6 5

[0184] According to Table 5, the increment of wet heat aldehydes in Comparative Examples 6 and 7 is relatively large.

[0185] Comparative Example 8: The raw material pretreatment in step 1 of Example 1 was eliminated, that is, the allyl alcohol polyether was directly subjected to the subsequent hydrosilylation reaction in step 2, and the rest was the same as Example 1.

[0186] Comparative Example 9-1: Change the "first stage, react at 85°C for 3 hours, second stage, cool to 65°C, and continue reacting for 5 hours" of Example 1 to "react at 85°C for 8 hours", and the rest is the same as Example 1.

[0187] Comparative Example 9-2: Change the "first stage, react at 85°C for 3 hours, second stage, cool to 65°C, and continue reacting for 5 hours" of Example 1 to "react at 65°C for 8 hours", and the rest is the same as Example 1.

[0188] The comparison of key data of the above cases is shown in Table 6.

[0189] Table 6

[0190]

[0191]

[0192] Note: All the above embodiments of the present invention meet the requirements of Fe 3+ and Cu 2+ The sum of the residual amounts is less than 2ppm.

[0193] Finally, it should be noted that the above are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by ordinary technicians in this field should be considered as the protection scope of the present invention.

Claims

1. Preparation method of FeNi-Mo@BNC catalyst, characterized in that It includes the following steps: Dissolve ferric chloride, nickel chloride and ammonium molybdate in a mixed solvent composed of alcohols and water, and then add phenylboronic acid and dicyandiamide to form a complex precursor solution; The complex precursor solution is prepared into a nanofiber membrane by electrospinning, and then through multi-stage pyrolysis and doping, pore regulation and surface activation, the Fe-Ni-Mo@BNC catalyst is obtained.

2. The preparation method of the FeNi-Mo@BNC catalyst according to claim 1, characterized in that It includes the following steps: ①. Preparation of the precursor solution: According to the molar ratio of ferric chloride:nickel chloride:ammonium molybdate = 1:0.24 - 0.35:0.03 - 0.05, dissolve the metal salts composed of ferric chloride, nickel chloride and ammonium molybdate in a mixed solvent composed of alcohols and water, and then add an aqueous solution of phenylboronic acid as a complexing agent and an aqueous solution of dicyandiamide, and stir evenly to form a complex precursor solution; The molar ratio of ferric chloride:phenylboronic acid = 1:(1.5 ± 0.1), and the molar ratio of ferric chloride:dicyandiamide = 1:(2.5 ± 0.1); ②. Preparation of composite fibers by electrospinning: Mix the complex precursor solution obtained in step ① with polyacrylonitrile, and stir magnetically for 24 ± 2 hours to form a homogeneous spinning solution; The mass ratio of polyacrylonitrile:complex precursor solution = (2 ± 0.2):1; Prepare the homogeneous spinning solution into a nanofiber membrane and then dry it; ③. Multi-stage pyrolysis and doping: Place the dried fiber membrane obtained in step ② in a tube furnace and carry out the reactions in the following stages in sequence: The first stage: Heat up to 400 ± 20 °C, introduce N2, and keep the temperature for reaction for 1 ± 0.1 hour; The second stage: Stop introducing N2, heat up to 850 ± 20 °C, and then switch to introducing a mixture of NH3 / BCl3, and the volume flow ratio of NH3:BCl3 = (5 ± 0.5):1; keep the temperature for reaction for 2 ± 0.1 hour; The third stage: Stop introducing the NH3 / BCl3 mixture, heat up to 900 ± 20 °C, and then switch to introducing a mixture of Ar / H2, so as to replace all the gases in the tube furnace with Ar / H2; then in the atmosphere of Ar / H2, keep the temperature for annealing reaction for 30 ± 5 minutes, and then cool to obtain the Fe-Ni-Mo@BNC crude product; the volume flow ratio of Ar:H2 = 94 - 96:4 - 6; ④. Pore regulation and surface activation Immerse the Fe-Ni-Mo@BNC crude product in a 0.08 - 0.12 mol / L NaOH solution and perform ultrasonic treatment for 2 ± 0.5 hours to achieve pore regulation; Then wash it with a 0.04 - 0.06 mol / L HNO3 solution, and finally place it in a tube furnace that has been heated up to 300 ± 20 °C, introduce a mixture of Ar / H2, and the volume flow ratio of Ar:H2 = 94 - 96:4 - 6, and keep the temperature for reduction reaction for 1 ± 0.1 hour; obtain the active catalyst FeNi-Mo@BNC.

3. The preparation method of the FeNi-Mo@BNC catalyst according to claim 2, characterized in that In step ①: For every 20 - 30 mmol of ferric chloride, 120 - 140 mL of the mixed solvent is used; In the mixed solvent, the volume ratio of alcohols:water = (4 ± 0.2):1; The concentration of the aqueous solution of phenylboronic acid is 0.25 - 0.35 mol / L, and the concentration of the aqueous solution of dicyandiamide is 0.45 - 0.55 mol / L.

4. The preparation method of the FeNi-Mo@BNC catalyst according to claim 3, characterized in that In step ①: The alcohol in the mixed solvent is ethylene glycol.

5. The preparation method of the FeNi-Mo@BNC catalyst according to any one of claims 2 to 4, characterized in that: In step ②: Prepare the nanofiber membrane by an electrospinning machine, and the parameters of the electrospinning machine are: voltage 18±1 kV, propulsion rate 1.2±0.1 mL / h, receiving distance 15±1 cm; The obtained fiber membrane is vacuum-dried at 80±10 °C for 12±1 hours to finally obtain a dried fiber membrane.

6. The preparation method of the FeNi-Mo@BNC catalyst according to claim 5, characterized in that: In step ③: The first stage: heat up to 400±20 °C at a rate of (3±0.5) °C / min, and the N2 flow rate per minute is 0.8-1.2% of the volume of the tubular furnace; The second stage: heat up to 850±20 °C at a rate of (5±0.5) °C / min, and the flow rate of the NH3 / BCl3 mixed gas per minute is 1.8-2.2% of the volume of the tubular furnace; In step ④: the flow rate of Ar / H2 per minute is 4-6% of the volume of the tubular furnace.

7. The FeNi-Mo@BNC catalyst prepared by the method according to any one of claims 1-6, characterized in that: The metal loading of the FeNi-Mo@BNC catalyst is Fe 4.0-4.5 wt%, Ni 1.0-1.5 wt%, Mo 0.4-0.6 wt%.

8. A method for reducing aldehyde substances in polyether polyol modified silicone oil, characterized in that: Select the FeNi-Mo@BNC catalyst, including the following steps: 1), Raw material pretreatment: Add ethylenediaminetetramethylenephosphonic acid as a complexing agent and diatomite as an adsorption carrier to allyl alcohol polyether, stir and react for 2 hours under the protection of an inert gas, and then centrifuge / filter to obtain pretreated allyl alcohol polyether; The addition amount of ethylenediaminetetramethylenephosphonic acid is 0.1%-0.5% of the mass of allyl alcohol polyether, and the addition amount of diatomite is 1%-3% of the mass of allyl alcohol polyether; 2), Hydrosilylation reaction: Under the action of the FeNi-Mo@BNC catalyst, all the pretreated allyl alcohol polyether obtained in step 1) and hydrogen-containing silicone oil are subjected to the following two-stage temperature-controlled reaction in turn under the protection of a slightly positive pressure inert gas: The first stage is to react at 75-90 °C for 2-5 hours; The second stage is to cool down to 60-70 °C and react for 5±0.5 hours; to obtain a crude product of polyether polyol modified silicone oil; The molar ratio of pretreated allyl alcohol polyether to hydrogen-containing silicone oil is 1:0.92-1.25; The total weight of the allyl alcohol polyether and hydrogen-containing silicone oil in step 1) is named the total weight of the raw materials; The dosage of the FeNi-Mo@BNC catalyst is 0.05%-0.15% of the total weight of the raw materials; The Si-H bond content of the hydrogen-containing silicone oil is 1.0-2.5 mol / kg; 3), Multi-stage adsorption purification: Add a composite adsorbent to all the crude polyether polyol modified silicone oil obtained in step 2), stir at 50±10 °C under vacuum conditions for 4±0.5 hours, and filter to obtain purified polyether modified silicone oil; The composite adsorbent is composed of activated carbon, β-cyclodextrin and amino-functionalized mesoporous SiO2 in a weight ratio of 1-5:1:1-5; The composite adsorbent is 1%-10% of the total weight of the raw materials; 4), Stabilization treatment: Triethanolamine and a hindered phenol antioxidant are added to the purified polyether-modified silicone oil obtained in all of step 3), and after vacuum degassing, filtration is carried out to obtain a polyether polyol-modified silicone oil; Triethanolamine: raw material total weight = mass ratio of 0.5% to 2%; Hindered phenol antioxidant: raw material total weight = mass ratio of 0.1% to 1%.

9. The method for reducing aldehyde substances in a polyether polyol-modified silicone oil according to claim 8, wherein: The hindered phenol antioxidant in step 4) is Irganox 1010.

10. The method for reducing aldehyde substances in polyether polyol modified silicone oil according to claim 9, characterized in that: In step 4): the vacuum degassing is carried out at 60 ± 10 °C for 1 hour; the filtration is carried out through a 0.45 μm filter membrane.

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