A platinum complex catalyst for hydrosilylation reaction and its preparation method and application

Abstract

The present invention relates to a platinum complex catalyst for hydrosilylation reaction, which is an organic ligand-platinum complex obtained by a ligand exchange reaction between a platinum (IV) compound and a first ligand to obtain a preligand; the first ligand is at least one of tetramethyl divinyl disiloxane, tetramethyl tetravinyl cyclotetrasiloxane, and vinyl silicone oil; the second ligand is an allyl polyether, and the structural formula is: wherein m and n are integers of 5 to 10, and the difference between n and m is within 4. The platinum complex catalyst provided by the present invention has high catalytic efficiency in hydrosilylation reaction, reduces isomerization side reactions, and reduces hydrogen generation during the reaction.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a platinum complex catalyst for hydrosilylation reaction and a preparation method and application thereof. Background Art

[0002] The hydrosilylation reaction is a type of reaction in which compounds containing Si-H bonds react with unsaturated organic matter under the action of a catalyst to form organosilicon compounds. The hydrosilylation reaction is the most studied and widely used type of reaction in organosilicon chemistry. It is one of the most important methods for synthesizing organosilicon products containing C-Si bonds in organosilicon chemistry. Through this reaction, a series of organosilicon compounds containing different functional groups that are difficult to obtain by other methods can be prepared. In the hydrosilylation reaction, the commonly used catalyst is a platinum complex catalyst, which mainly has two categories: the first category is the Speier catalyst, which is an isopropanol solution of chloroplatinic acid; the second category is the Karstedt catalyst, which is developed on the basis of the Speier catalyst. Chloroplatinic acid or chloroplatinate is heated in ethanol with vinyl siloxane and sodium bicarbonate to form a platinum vinyl siloxane complex. Compared with the Speier catalyst, the catalytic efficiency of the Karstedt catalyst is higher. The Karstedt catalyst is still the most commonly used catalyst in the hydrosilylation reaction today. However, the catalytic efficiency of this type of catalyst needs to be further improved, especially in the hydrosilylation reaction of olefins with special functional groups (such as epoxy, acryloxy, etc.). In addition, Karstedt catalysts are accompanied by a variety of side reactions in the hydrosilylation reaction, producing unwanted isomerization byproducts; in addition, hydrogen is easily generated during the hydrosilylation process, and the product is prone to yellowing.

[0003] The applicant disclosed a complex platinum catalyst for the production of epoxy-terminated silicone oil and its preparation method and application in the previous patent CN110252411B. The complex platinum catalyst is an organic ligand-platinum complex obtained by complexing a compound containing platinum (II) with a first ligand and a second ligand. The first ligand is at least one of tetramethyldivinyldisiloxane, acetylacetone or ethyl acetoacetate, and the second ligand is N,N'-bis(diphenylphosphine)piperazine or N,N'-bis(diphenylphosphinemethyl)piperazine. The present invention provides a complex platinum catalyst for the production of epoxy-terminated silicone oil. A very high yield can be obtained at a very low dosage, but the catalytic efficiency needs to be further improved, and there is no improvement in reducing the isomerization side reaction during the reaction. Summary of the invention

[0004] In order to solve the shortcomings of the above-mentioned prior art that the catalytic activity of platinum catalysts for hydrosilylation reaction needs to be further improved, and there are many isomerization side reactions and a lot of hydrogen released during the reaction, the present invention provides a platinum complex catalyst for hydrosilylation reaction, which has high catalytic activity, reduces isomerization side reactions during the reaction, and reduces the generation of hydrogen.

[0005] The present invention achieves the above object through the following technical solutions:

[0006] A platinum complex catalyst for hydrosilylation reaction is an organic ligand-platinum complex obtained by complexing a platinum (IV) compound with a first ligand to obtain a preligand, and then reacting the preligand with a second ligand through a ligand exchange reaction; the first ligand is at least one of tetramethyldivinyldisiloxane, tetramethyltetravinylcyclotetrasiloxane, and vinyl silicone oil; the second ligand is an allyl polyether, and the structural formula is as follows:

[0007]

[0008] Among them, m and n are integers of 5 to 10, and the difference between n and m is within 4, for example, the difference between n and m is 4, 3, 2, 1, and 0.

[0009] The allyl polyether is an oligomer with good flexibility, in which the lengths of the two segments are close, that is, the ratios of the hydrophilic group and the lipophilic group are close, achieving a balance between hydrophilicity and hydrophobicity; and has good compatibility with the raw material olefinic compound in the hydrosilylation reaction. The inventor unexpectedly found that by adding the allyl polyether to the preligand formed by the complexation of the platinum (IV) compound and the first ligand for partial ligand exchange, a new platinum complex catalyst is formed, and its catalytic efficiency in the hydrosilylation reaction is greatly improved compared with the general complex type platinum catalyst.

[0010] Preferably, the molar ratio of the first ligand to the second ligand is 1:(1-3), more preferably 1:(2-3). The reaction activity of the second ligand is lower than that of the first ligand. The excess second ligand in the present invention ensures that part of the first ligand can be replaced during the ligand exchange reaction, and also improves the uniformity of the prepared platinum complex catalyst in the reactants.

[0011] Preferably, the mass ratio of the platinum (IV) compound to the first ligand is 1:(8-20), more preferably 1:(10-15).

[0012] The platinum (IV)-containing compound is not particularly limited, as long as it is a substance that can produce Pt (IV) in the above system, including but not limited to at least one of H2PtCl6 and PtCl4; the platinum (IV)-containing compound also includes hydrates of the above compounds, including H2PtCl6·xH2O, PtCl4·xH2O, where x is an integer between 1 and 6.

[0013] In a second aspect, the present invention also provides a method for preparing the above-mentioned platinum complex catalyst for hydrosilylation reaction, comprising the following steps:

[0014] (S1) Complexation: Add a platinum (IV) compound, a first ligand and an acid-binding agent to an organic solvent, react at 40 to 65° C. for 3 to 6 hours, filter and wash to remove the acid-binding agent after the reaction, and then remove the solvent under vacuum to obtain a preligand;

[0015] (S2) Ligand exchange: The preligand and the second ligand are mixed, reacted at 40-65° C. for 1-3 hours, and then low boiling products are removed at 80-120° C. under vacuum to obtain a platinum complex catalyst.

[0016] Preferably, in step (S1), the mass ratio of the platinum (IV) compound to the acid binding agent is 1:(1-5).

[0017] Preferably, in step (S1), the acid binding agent is at least one of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, magnesium carbonate, and calcium carbonate; and the organic solvent is at least one of N,N-dimethylacetamide, N-methylpyrrolidone, methanol, ethanol, n-propanol, isopropanol, tetrahydrofuran, acetone, ethyl acetate, dichloromethane, and chloroform.

[0018] Preferably, in step (S1), the washing is performed using ethanol or isopropanol as a washing agent; and the vacuum degree is between -0.05 MPa and -0.09 MPa.

[0019] In step (S2), the second ligand undergoes an exchange reaction with the first ligand in the preligand, thereby replacing part of the first ligand. The replaced first ligand has a lower boiling point than the second ligand and can be released at 80-120°C under vacuum.

[0020] Preferably, step (S2) further comprises adding an antioxidant after the low-boiling products are removed, wherein the amount of the antioxidant added is (1 to 5) times the mass of the platinum (IV) compound; the antioxidant is at least one of tri-n-butylamine, triphenylamine, triphenylphosphine, hexahydropyridine, and 2,2′-bipyridine. The addition of the antioxidant can improve the antioxidant and yellowing resistance of the catalyst.

[0021] In a third aspect, the present invention also provides the use of the aforementioned platinum complex catalyst in a hydrosilylation reaction, wherein the amount used is 5 to 50 ppm (based on Pt content) of the reaction system, preferably 10 to 20 ppm (based on Pt content). Hydrosilylation reaction refers to a type of reaction in which a compound containing a Si-H bond reacts with an unsaturated organic matter under the action of a catalyst to generate an organosilicon compound, and the reaction system described herein is the sum of the compound containing a Si-H bond and the unsaturated organic matter.

[0022] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0023] (1) The inventors unexpectedly discovered that by adding an allyl polyether of a specific structure to a preligand formed by complexing a platinum (IV) compound with a first ligand, i.e., a general complex-type platinum catalyst, partial ligand exchange was performed to form a new platinum complex catalyst, whose catalytic efficiency was greatly improved compared with that of a general complex-type platinum catalyst.

[0024] (2) The novel platinum complex catalyst provided by the present invention not only has high catalytic efficiency in the hydrosilylation reaction, but also reduces isomerization side reactions and reduces hydrogen generation during the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the DSC curve of the raw material mixture of Application Example 1.

[0026] Figure 2 The DSC curve of the raw material mixture of Comparative Application Example 1 is shown in FIG.

[0027] Figure 3 The H1-NMR spectra of the organosilicon products prepared in Application Example 1 and Comparative Application Example 1 and Comparative Application Example 2 are shown.

[0028] Figure 4 This is the hydrogen release curve during the preparation of the organosilicon product in Application Example 1 and Comparative Application Example 1 and Comparative Application Example 2. DETAILED DESCRIPTION

[0029] The platinum complex catalyst of the present invention and the production of organosilicon products using the catalyst are further described in detail below in conjunction with specific examples. Unless otherwise specified, all reagents used are commercially available reagents in the art.

[0030] Allyl polyether JQYN-F4 (molecular weight 568), JQYN-F9 (molecular weight 888), JQYN-F6 (molecular weight 758), and HMS-260B (molecular weight 938) were all selected from Nanjing Jinqi Chemical Group Co., Ltd.

[0031] Example 1

[0032] (S1) adding 1 g of H2PtCl6·6H2O to 50 g of isopropanol, and then adding 15 g of tetramethyltetravinylcyclotetrasiloxane and 1.6 g of sodium bicarbonate, and reacting at 60°C for 3 to 6 hours until the color of the sodium bicarbonate changes to off-white; after filtering out the sodium bicarbonate, the solvent is removed at -0.08 MPa to obtain a preligand;

[0033] (S2) All of the above preligands were mixed with 74.1 g of allyl polyether JQYN-F4 (i.e., the molar ratio of tetramethyltetravinylcyclotetrasiloxane to allyl polyether was 1:3), and then reacted at 50° C. for 1.5 h; then the temperature was raised to 100° C., and low-boiling substances were removed at -0.08 MPa, and a total of 8 g of low-boiling substances were removed to obtain a platinum complex catalyst with a platinum content of 0.46%. The structural formula of the allyl polyether JQYN-F4 is:

[0034]

[0035] Example 2

[0036] (S1) adding 1 g of H2PtCl6·6H2O to 50 g of isopropanol, and then adding 10 g of tetramethyldivinyldisiloxane and 1.5 g of sodium bicarbonate, and reacting at 60°C for 3 to 6 h until the color of the sodium bicarbonate changes to off-white; filtering out the sodium bicarbonate, and then removing the solvent at -0.08 MPa to obtain a preligand;

[0037] (S2) All of the above preligands were mixed with 95.4 g of allyl polyether JQYN-F9 (i.e., the molar ratio of tetramethyl divinyl disiloxane to allyl polyether was 1:2), and then reacted at 60° C. for 2 h, and then heated to 100° C., and low-boiling substances were removed at -0.08 MPa, and a total of 6 g of low-boiling substances were removed to obtain a platinum complex catalyst with a platinum content of 0.37%. The structural formula of the allyl polyether JQYN-F9 is:

[0038]

[0039] Example 3

[0040] (S1) adding 1 g of H2PtCl6·6H2O to 60 g of isopropanol, and then adding 15 g of tetramethyldivinyldisiloxane and 2.0 g of sodium bicarbonate, and reacting at 60°C for 3 to 6 h until the color of the sodium bicarbonate changes to off-white; filtering out the sodium bicarbonate, and then removing the solvent at -0.08 MPa to obtain a preligand;

[0041] (S2) All of the above preligands were mixed with 122.3 g of allyl polyether JQYN-F6 (i.e., the molar ratio of tetramethyl divinyl disiloxane to allyl polyether was 1:2), and then reacted at 60° C. for 2 h, and then heated to 100° C., and low-boiling substances were removed at -0.08 MPa, and a total of 6 g of low-boiling substances were removed to obtain a platinum complex catalyst with a platinum content of 0.28%. The structural formula of the allyl polyether JQYN-F6 is:

[0042]

[0043] Example 4

[0044] (S1) adding 1 g of H2PtCl6·6H2O to 50 g of isopropanol, and then adding 8 g of tetramethyldivinyldisiloxane and 2.0 g of sodium bicarbonate, and reacting at 60°C for 3 to 6 h until the color of the sodium bicarbonate changes to off-white; filtering out the sodium bicarbonate, and then removing the solvent at -0.08 MPa to obtain a preligand;

[0045] (S2) All of the above-mentioned preligands are mixed with 32.6 g of allyl polyether JQYN-F6 (i.e., the molar ratio of tetramethyldivinyldisiloxane to allyl polyether is 1:1), and then reacted at 60°C for 2 hours, and then the temperature is raised to 100°C, and low-boiling substances are removed at -0.08 MPa. A total of 2.5 g of low-boiling substances are removed to obtain a platinum complex catalyst with a platinum content of 0.95%.

[0046] Example 5

[0047] (S1) adding 1 g of H2PtCl6·6H2O to 60 g of isopropanol, and then adding 20 g of tetramethyldivinyldisiloxane and 3.0 g of sodium bicarbonate, and reacting at 60°C for 3 to 6 hours until the color of the sodium bicarbonate changes to off-white; after filtering out the sodium bicarbonate, the solvent is removed at -0.08 MPa to obtain a preligand;

[0048] (S2) All of the above-mentioned preligands are mixed with 163 g of allyl polyether JQYN-F6 (i.e., the molar ratio of tetramethyldivinyldisiloxane to allyl polyether is 1:2), and then reacted at 60°C for 2 hours, and then the temperature is raised to 100°C, and low-boiling substances are removed at -0.08 MPa. A total of 10 g of low-boiling substances are removed to obtain a platinum complex catalyst with a platinum content of 0.21%.

[0049] Comparative Example 1

[0050] The other conditions were the same as those in Example 1, except that step (S2) was omitted and the preligand with a platinum content of 2.31% obtained in step (S1) was directly used as a platinum complex catalyst.

[0051] Comparative Example 2

[0052] The other conditions are the same as those in Example 1, except that 121.8 g of allyl polyether HMS-260B is used in step (S2) to replace 74.1 g of allyl polyether JQYN-F4 (i.e., equimolar substitution) to obtain a platinum complex catalyst with a platinum content of 0.29%. The structural formula of the allyl polyether HMS-260B is:

[0053]

[0054] Application Example 1

[0055] 150 g of hydrogen-containing silicone oil with a hydrogen content of 0.1%, 17.1 g of allyl glycidyl ether and 0.55 g of the platinum complex catalyst prepared in Example 1 (i.e., 15 ppm in terms of Pt) were mixed, and then the temperature was raised to 80° C. to carry out a hydrosilylation reaction for 5 hours. After maintaining the temperature and removing low-boiling substances, an organosilicon product was obtained.

[0056] Application Example 2

[0057] Other conditions are the same as those in Application Example 1, except that the platinum complex catalyst is prepared from Example 2 and the amount used is 0.68 g (ie, 15 ppm in terms of Pt).

[0058] Application Example 3

[0059] Other conditions are the same as those in Application Example 1, except that the platinum complex catalyst is prepared from Example 3 and the amount used is 0.90 g (ie, 15 ppm in terms of Pt).

[0060] Application Example 4

[0061] Other conditions are the same as those in Application Example 1, except that the platinum complex catalyst is prepared from Example 4 and the amount used is 0.26 g (ie, 15 ppm in terms of Pt).

[0062] Application Example 5

[0063] Other conditions are the same as those in Application Example 1, except that the platinum complex catalyst is prepared from Example 5 and the amount used is 1.19 g (ie, 15 ppm in terms of Pt).

[0064] Comparative application example 1

[0065] Other conditions are the same as those in Application Example 1, except that the platinum complex catalyst is prepared from Comparative Example 1 and the amount used is 0.11 g (ie, 15 ppm in terms of Pt).

[0066] Comparative Application Example 2

[0067] Other conditions are the same as those in Application Example 1, except that the platinum complex catalyst is prepared from Comparative Example 2 and the amount used is 0.86 g (ie, 15 ppm in terms of Pt).

[0068] Analysis and Results

[0069] 1) DSC thermal analysis: The raw materials of the corresponding application example and the comparative application example are mixed and subjected to DSC test at a test temperature of 20 to 130°C. The DSC curve of the raw material mixture of application example 1 is as follows: Figure 1 As shown, the DSC curve of the raw material mixture of comparative application example 1 is as follows Figure 2 shown.

[0070] from Figure 1 and Figure 2 From the comparison of the DSC curves, it can be seen that under the same catalyst usage (in terms of Pt, 15 ppm), the initial reaction temperature of the platinum complex catalyst prepared in Example 1 of the present invention is 49.95°C, which is lower than 54.62°C of Comparative Example 1. The lower the initial reaction temperature, the shorter the induction time in the hydrosilylation reaction process, and the greater the catalyst reaction activity.

[0071] 2) Mass spectrometry test: The organic products prepared in the corresponding application examples and comparative application examples were subjected to nuclear magnetic analysis using a nuclear magnetic mass spectrometer from Bruker, Switzerland. The H1-NMR spectra of the organic silicon products prepared in application example 1 and comparative application example 1 and comparative application example 2 are shown in FIG. Figure 3 shown.

[0072] exist Figure 3 In the figure, the chemical shift δ=0.4ppm is the Si-CH2-CH2-peak produced by the addition of Si-H and C=C; the chemical shift δ=4.7ppm is the CH3-CH=CH-peak produced by the isomerization of CH2=CH-CH2, and its peak area reflects the amount of isomerized double bonds; the chemical shift δ=5.3ppm is the peak produced by residual CH2=CH, and its corresponding peak area reflects the amount of residual double bonds. Through fitting calculation, it is found that at δ=4.7ppm, the peak area of ​​Application Example 1 is 0.11, which is lower than 0.32 of Comparative Application Example 1 and 0.25 of Comparative Application Example 2, that is, the ratio of isomerized double bonds of the platinum complex catalyst prepared in Example 1 when catalyzing the hydrosilylation reaction is lower than that of the catalysts in Comparative Example 1 and Comparative Example 2, indicating that the platinum complex catalyst prepared in Example 1 can reduce the isomerization side reaction of double bonds. At δ=5.3ppm, the peak area of ​​Application Example 1 is only 0.03, which is lower than 0.12 of Comparative Application Example 1 and 0.09 of Comparative Application Example 2. That is, the residual double bonds in the system of the platinum complex catalyst prepared in Example 1 after catalyzing the hydrosilylation reaction are lower than those of the catalysts in Comparative Examples 1 and 2, indicating that the catalytic efficiency of the platinum complex catalyst prepared in Example 1 is higher.

[0073] 3) Hydrogen release test: The hydrogen release during the silanization reaction of the corresponding application example and the comparative application example was tested using Agilent Mirc-GC990, with argon as the carrier gas and a carrier gas flow rate of 80 ml / min; the test interval was 80 s; and the total test time was 230 min. The hydrogen release curves during the preparation of the organosilicon product in Application Example 1 and Comparative Application Example 1 and Comparative Application Example 2 are shown in the figure. Figure 4 shown.

[0074] from Figure 4 It can be seen that the hydrogen release rate during the preparation process of Application Example 1 is significantly lower than that of Comparative Application Example 1 and Comparative Application Example 2.

[0075] 4) Determination of residual hydrogen content after silanization lengthening reaction: According to the test method in "HG / T 4804-2015 Methyl High Hydrogen Silicone Oil", the residual hydrogen content of the prepared silicone products corresponding to the use case and comparative application example is tested.

[0076] The yields of the organosilicon products prepared in the application examples and comparative application examples are shown in Table 1.

[0077] Table 1 Residual hydrogen content

[0078] Group Residual hydrogen content (ppm) Application Example 1 18 Application Example 2 15 Application Example 3 14 Application Example 4 24 Application Example 5 21 Comparative application example 1 60 Comparative Application Example 2 41

[0079] As can be seen from Table 1, the residual hydrogen content in the organosilicon product obtained by using the platinum complex catalyst provided by the present invention for hydrosilylation reaction is significantly lower than that in the comparative application example, both of which are lower than 25 ppm, indicating that the platinum complex catalyst provided by the present invention has very excellent catalytic efficiency in the process of hydrosilylation reaction.

[0080] The above specific implementations are only illustrative of the content of the present invention and do not represent limitations of the content of the present invention. Those skilled in the art can imagine that the specific structure of the present invention may have other variations.

Claims

1. A platinum complex catalyst for hydrosilylation reaction, characterized in that: The organic ligand-platinum complex is obtained by a complexation reaction between a platinum (IV) compound and a first ligand to obtain a preligand, and then a ligand exchange reaction with a second ligand; the first ligand is at least one of tetramethyldivinyldisiloxane, tetramethyltetravinylcyclotetrasiloxane, and vinyl silicone oil; the second ligand is an allyl polyether, and the structural formula is as follows: Wherein, m and n are integers of 5 to 10, and the difference between n and m is within 4.

2. The platinum complex catalyst according to claim 1, characterized in that The molar ratio of the first ligand to the second ligand is 1:(1-3); more preferably 1:(2-3).

3. The platinum complex catalyst according to claim 1, characterized in that The mass ratio of the platinum (IV) compound to the first ligand is 1:(8-20); more preferably 1:(10-15).

4. The platinum complex catalyst according to claim 1, characterized in that The platinum (IV)-containing compound includes at least one of H2PtCl6 and PtCl4; the platinum (IV)-containing compound also includes hydrates of the above compounds, including H2PtCl6·xH2O and PtCl4·xH2O, where x is an integer between 1 and 6.

5. The method for preparing the platinum complex catalyst according to any one of claims 1 to 4, characterized in that: The following steps are involved: (S1) Complexation: Add a platinum (IV) compound, a first ligand and an acid-binding agent to an organic solvent, react at 40 to 65° C. for 3 to 6 hours, filter and wash to remove the acid-binding agent after the reaction, and then remove the solvent under vacuum to obtain a preligand; (S2) Ligand exchange: The preligand and the second ligand are mixed, reacted at 40-65° C. for 1-3 hours, and then low boiling products are removed at 80-120° C. under vacuum to obtain a platinum complex catalyst.

6. The preparation method according to claim 5, characterized in that: In step (S1), the mass ratio of the platinum (IV) compound to the acid binding agent is 1:(1-5).

7. The preparation method according to claim 5, characterized in that: In step (S1), the acid binding agent is at least one of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, magnesium carbonate, and calcium carbonate; and the organic solvent is at least one of N,N-dimethylacetamide, N-methylpyrrolidone, methanol, ethanol, n-propanol, isopropanol, tetrahydrofuran, acetone, ethyl acetate, dichloromethane, and chloroform.

8. The preparation method according to claim 5, characterized in that: In step (S1), the washing is performed using ethanol or isopropanol as a washing agent; the vacuum degree is between -0.05MPa and -0.09MPa.

9. The preparation method according to claim 5, characterized in that: Step (S2) also includes adding an antioxidant after the low boiling point product is removed, and the amount of the antioxidant added is (1 to 5) times the mass of the platinum (IV) compound; the antioxidant is at least one of tri-n-butylamine, triphenylamine, triphenylphosphine, hexahydropyridine, and 2,2′-bipyridine.

10. Use of the platinum complex catalyst according to any one of claims 1 to 4 in a hydrosilylation reaction, characterized in that: The dosage thereof is 5 to 50 ppm (based on Pt content) of the reaction system, preferably 10 to 20 ppm (based on Pt content).

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