CN115340570A - Alkynyl phosphite ligand, preparation method thereof and application thereof in hydrosilylation platinum catalyst - Google Patents

Abstract

The invention discloses an alkynyl phosphite ligand and its preparation method and its application in a hydrogen silylation platinum catalyst. The preparation method of the alkynyl phosphite ligand in the invention is: using phosphite The compound and the acetylenic alcohol compound are obtained by transesterification under the condition of 90-150 DEG C and adding a basic catalyst. The preparation method has the characteristics of low cost, readily available reactants, low toxicity, simple reaction conditions and high product yield. The alkynyl phosphite ligand described in the present invention is used in the preparation of a platinum hydrosilylation catalyst, and the prepared platinum catalyst has the characteristics of good stability, colorless and transparent, less prone to yellowing, and strong catalytic activity; Platinum catalysts are added to vinyl-containing silicone oil or silicone rubber, so that the silicone rubber can obtain longer low-temperature storage stability without adding additional reaction inhibitors.

Description

A kind of alkynyl phosphite ligand and its preparation method and platinum catalyst in hydrosilylation application in

technical field

The invention belongs to the field of hydrosilylation-type silicone rubber platinum catalysts, and in particular relates to an alkynyl phosphite ligand, a preparation method thereof, and an application in a hydrosilylation platinum catalyst.

Background technique

Silicone rubber can be used to produce products through various molding methods such as injection molding, compression molding, extrusion molding, etc., and its products can reach food-level safety, so it has more and more advantages in the fields of medical treatment, food packaging, tableware, and wearable smart products. more and more applications. Silicone rubber is usually vulcanized by peroxide or cross-linked with hydrogen-containing silicone oil as a cross-linking agent under the action of a transition metal catalyst. At present, the most widely used transition metal catalyst in industry is Karstedt catalyst. Karstedt catalyst has the advantages of strong catalytic activity and good compatibility with organosilicon systems, but it also has the disadvantage of short operating time at room temperature. Therefore, when using Must be used with inhibitors. Alkynyl alcohols, maleates, fumarates, and phosphites are commonly used inhibitors of hydrosilylation reactions.

In order to obtain platinum catalysts with high stability and high activity, the ligands of platinum complex catalysts can generally be modified. It is currently known that the use of N-containing compounds or organic phosphine ligands with reasonable structures can effectively prolong the service life of platinum catalysts in low temperature environments without losing high-temperature catalytic activity. For example, documents Kownacki I, Marciniec B, Steinberger H, et al.Effect of triorganophosphites on platinum catalyzed curing of silicon rubber [J]. Applied Catalysis A General, 2009, 362(1-2): 106-114. Using PCl ₃ and alkanes Synthesis of a series of phosphite ligands by alcohol synthesis, using triorganophosphite modified Karstedt catalysts with substituents with different electronic effects and steric hindrances, adding to silicone rubber can make the storage time of silicone rubber at room temperature from a few minutes It can be extended to more than 7 days, and at the same time, it can be completely cured and formed within 10 minutes at 120°C. This method can effectively prolong the room temperature storage time of the organosilicon crosslinking system, but the _PCl3 used is highly toxic, and the reaction steps are relatively complicated, which is not conducive to industrial production.

Contents of the invention

In order to overcome the deficiencies in the prior art, the primary purpose of the present invention provides a method for preparing an alkynyl phosphite ligand. The preparation method has low reaction cost, easy access to reactants and low toxicity, simple reaction conditions and high product yield. High rate.

The second object of the present invention is the alkynyl phosphite ligand prepared by the above preparation method.

A third object of the present invention is the use of alkynyl phosphite ligands in platinum hydrosilylation catalysts.

The first purpose of the present invention is achieved through the following technologies:

A kind of preparation method of alkynyl phosphite ligand, concrete steps are:

Alkyne alcohol compounds, phosphite compounds, basic catalysts, and organic solvents are prepared in a molar ratio of 1:5 to 10:0.15 to 0.3:2 to 10. Under nitrogen protection, stir and heat up to 90 to 150°C for reaction 3 ~5 hours, until the condensing device does not produce condensate, washing, filtering, impurity removal, negative pressure vacuum distillation, to obtain the product alkynyl phosphite ligand shown in structural formula (1),

Wherein, R ₁ , R ₂ , and R ₃ are alkyl groups containing 1 to 8 C atoms, and R ₁ , R ₂ , and R ₃ may be the same or different.

Preferably, the preparation method of the alkynyl phosphite ligand specifically comprises the following steps:

(1) Add acetylenic alcohol compounds, phosphite compounds, basic catalysts, and organic solvents into a three-necked flask in proportion, raise the temperature to 90-150°C under nitrogen protection and stirring, and react for 3-5 hours until the condensing device No condensate occurs, giving mixture I;

(2) Add the mixture I described in step (1) into deionized water, filter 3 times, remove impurities such as catalyst and solvent, and obtain mixture II;

(3) Vacuum distillation of the mixture II in step (2) for 3 to 5 hours under negative pressure to remove residual reactants, deionized water and solvent to obtain a white powder product alkynyl phosphite ligand.

Preferably, the acetylenic alcohol compound is a type of alkanes containing both carbon-carbon triple bonds and hydroxyl groups.

Preferably, the acetylenic alcohol compounds are 2-methyl-3-butyn-2-ol, 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, 3 -Methyl-1-dodeyn-ol, 3,7,11-trimethyldodeyn-3-ol, 3,6-dimethyl-1-heptyn-3-ol or 3-methyl-1 - at least one of octyn-3-ol.

Preferably, the phosphite compound refers to a class of compounds shown in structural formula (2),

Wherein R ₁ , R ₂ , and R ₃ are alkyl groups containing 1 to 8 C atoms, and R ₁ , R ₂ , and R ₃ can be the same or different.

Preferably, the phosphite compound is at least one of trimethyl phosphite, triethyl phosphite and tributyl phosphite.

Preferably, the basic catalyst is one of NaHCO ₃ , Na ₂ CO ₃ , NaOH, KOH or triethylamine.

Preferably, the organic solvent is one of n-hexane, n-heptane, cyclohexane, toluene, xylene, petroleum ether or methylene chloride.

The second purpose of the present invention is achieved through the following technologies:

An alkynyl phosphite ligand prepared by the above preparation method.

The third purpose of the present invention is achieved through the following technologies:

Application of an alkynyl phosphite ligand in a platinum hydrosilylation catalyst.

In the preparation method provided by the invention, the alkynyl phosphite ligand is obtained through transesterification of a phosphite compound and an alkynyl alcohol compound under the action of a basic catalyst and an organic solvent. It is well known that both phosphite compounds and acetylenic alcohols have been proven to be effective inhibitors of Karstedt catalysts. The alkynyl phosphite ligand obtained by the preparation method mentioned in the present invention can effectively combine the characteristics of the two inhibitors. The use of alkynyl phosphite ligands to modify Karstedt catalysts, due to the electron-withdrawing effect of unsaturated phosphorus atoms and the steric hindrance effect of substituents, on the one hand, can make platinum catalysts prepared using this ligand work at low temperatures. It has quite low catalytic activity; on the other hand, when the temperature rises, the unsaturated phosphorus atoms are oxidized, and the activity of the catalyst is restored, which can efficiently and quickly catalyze the hydrosilylation reaction of silicone rubber, and obtain a three-dimensional network structure vulcanized rubber.

In the preparation method provided by the present invention, the alkynyl alcohol compound refers to an alcohol compound containing an alkynyl group and different numbers of hydroxyl groups in the molecule, and is often used as a reaction inhibitor of a hydrosilylation reaction. Phosphite compounds refer to a class of compounds with unsaturated phosphorus atoms obtained by the esterification reaction of phosphorous acid and alcohols or phenolic compounds. They are generally used as an efficient antioxidant in industrial production and can be used in extrusion Improve the color and processing thermal stability of polymer materials during use in fields such as calendering, film blowing, and casting.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The preparation method provided by the present invention prepares the alkynyl phosphite ligand through a simple, low-energy-efficiency transesterification reaction, the reaction product is non-toxic or low-toxic, and the reaction operation is simple;

(2) In the preparation method provided by the present invention, the obtained alkynyl phosphite ligand is used to prepare a platinum catalyst for one-component addition-type heat-cured silicone rubber, and it is not necessary to add an inhibitor to the rubber compound during use. It only needs to mix the base rubber, the catalyst and the crosslinking agent, and the obtained silicone rubber composition has a long working time.

(3) The preparation method provided by the present invention is easy to control, safe and pollution-free, simple to operate, high in production efficiency, and suitable for industrial production.

Description of drawings

Fig. 1 is the infrared spectrogram of three (methylbutyne) phosphite and three (cyclohexylacetylene) phosphite prepared in embodiment 1;

Fig. 2 is the infrared spectrogram of tris (methylbutyne) phosphite and tris (cyclohexylacetylene) phosphite prepared in Example 2.

Detailed ways

The specific implementation of the present invention will be further described below in conjunction with examples, but the implementation and protection of the present invention are not limited thereto. It should be pointed out that, if there are any processes in the following that are not specifically described in detail, those skilled in the art can realize or understand with reference to the prior art. The reagents or instruments used were not indicated by the manufacturer, and they were regarded as conventional products that can be purchased from the market.

In the following examples, the operational time of silicone rubber is tested according to GB/T 7123.1-2015.

Example 1

(1) Place a three-neck flask on a collector-type constant temperature heating magnetic stirrer (Shanghai Lichen Instrument Technology Co., Ltd., model DF-101S), adjust the heating temperature to 100 ° C, and the rotor speed to 200 rpm. 8.4g (0.1mol) of methyl butynol, 83g (0.5mol) of triethyl phosphite, 30g of xylene and 1g of NaOH were put into the three-necked flask in sequence, fully reacted for 3.5h, and it was observed that there was no new Droplets are formed, stopping the reaction.

(2) step (1) gained mixture is filtered three times with 100ml deionized water, gets filtrate and carries out vacuum negative pressure suction filtration process, fully removes residual unreacted solvent, xylene and catalyzer in the mixed solution, obtains 22.4g tri( Methylbutyne) phosphite, the yield was 68.3%.

(3) 100g Karstedt platinum catalyst (platinum concentration is 5000ppm) is joined in the there-necked flask, 1.68g step (2) gained tris (methylbutyne) phosphite is added thereto under 70 ℃ of stirring conditions, fully reacts 1 After 1 hour, 398.32g of xylene was added thereto, and the platinum catalyst C1 (platinum concentration of 1000ppm) was obtained after stirring evenly, and the molar ratio of Pt atoms to P atoms was 1:2.

As shown in Figure 1 is the infrared spectrogram of tris (methylbutyne) phosphite and tris (cyclohexylacetylene) phosphite prepared in this embodiment.

Example 2

The preparation process is similar to Example 1, except that 6.3g of ethynylcyclohexanol (ECH) is added in step (1) to obtain 26.88g of three (cyclohexylacetylene) phosphite (productivity is 58.4%), Step (2) added 2.36 g of tris(cyclohexylacetylene) phosphite and 397.64 g of xylene. The platinum catalyst C2 (platinum concentration of 1000ppm) was obtained, and the molar ratio of Pt atoms to P atoms was 1:2.

Fig. 2 is the infrared spectrogram of tris(methylbutyne) phosphite and tris(cyclohexylacetylene) phosphite prepared in this embodiment.

Comparative example 1

Add 100g Karstedt platinum catalyst (platinum concentration is 5000ppm) into a three-necked flask, add 0.85g triethyl phosphite to it under stirring condition at 70°C, fully react for 1 hour, then add 399.15g xylene to it, and stir evenly Finally, platinum catalyst C3 (platinum concentration of 1000ppm) was obtained, and the molar ratio of Pt atoms to P atoms was 1:2.

Comparative example 2

Because acetylenic alcohol compound and Karstedt catalyst are mixed and placed, Pt(0) in Karstedt catalyst will be rapidly oxidized in the air, producing a large amount of platinum black, which will seriously affect the catalytic activity of the catalyst, so comparative example 2 considers Karstedt catalyst and ethynyl ring Hexanol was added to the silicone rubber in batches, and the addition amount was also such that the molar ratio of Pt atoms to ECH was 1:2.

a. Test of high temperature vulcanization speed

Take 50g of methyl vinyl liquid silicone rubber with a hardness of 40 degrees after vulcanization (Hesheng Silicon Industry Co., Ltd.), add 1.2g of hydrogen-containing silicone oil (hydrogen content is 0.75%) blocked by Si-H bonds, stir well and then add 0.25g of the catalysts C1-C3 prepared by the above method were stirred evenly to obtain a silicone rubber composition. Take another 50g of methyl vinyl liquid silicone rubber with a hardness of 40 degrees after vulcanization, add 1.2g of hydrogen-containing silicone oil terminated by Si-H bonds (hydrogen content is 0.75%), stir well and then add 0.03g of xylene Diluted 100-fold ethynyl cyclohexanol, stirred evenly, added 0.05g of Karstedt catalyst (platinum concentration is 5000ppm) and stirred evenly, marked as comparative sample C4.

The above silicone rubber composition was taken and tested with a rotorless vulcanizer (Dongguan Cree Instrument Co., Ltd.), with a mold temperature of 150° C., to test the vulcanization rate of the silicone rubber composition at high temperature.

The following table 1 is the result table of the vulcanization of the silicone rubber composition catalyzed at high temperature by the products prepared in Examples 1 to 2 and Comparative Example 1, wherein the C4 comparative sample has no data because the corresponding silicone rubber composition is added after the Karstedt catalyst The cross-linking reaction occurred during the mixing process, and the rubber compound lost its fluidity, and the corresponding vulcanization test could no longer be carried out.

The high-temperature catalytic effect of table 1 embodiment, comparative example

It can be seen from Table 1 that, except for the C4 control sample that cannot be tested for vulcanization, the other three samples can be completely cured within 8 minutes at a high temperature of 150°C.

b. Test of room temperature vulcanization speed

Take 100g of vinyl silicone oil with a viscosity of 350mpa s (Hesheng Silicon Industry Co., Ltd.), add 2.4g of hydrogen-containing silicone oil (hydrogen content is 0.75%) terminated by Si-H bonds, stir well and add 0.5g of Example 1 To the catalysts C1-C3 prepared in 2 and Comparative Example 1, stir evenly to obtain a silicone rubber composition. Take another 100g of vinyl silicone oil with a viscosity of 350mpa·s, add 2.4g of hydrogen-containing silicone oil blocked by Si-H bonds (hydrogen content is 0.75%), stir evenly, add 0.06g of vinyl silicone oil diluted 100 times with xylene Ethynyl cyclohexanol, stir evenly, add 0.1g Karstedt catalyst (platinum concentration is 5000ppm) and stir again, marked as comparative sample C5. All the samples were sealed and placed in an environment of 25° C., and the viscosity of the composition was measured regularly with a rotational viscometer (Shanghai Changji Geological Instrument Co., Ltd., model: NDJ-8S).

The specific test results of the viscosity growth of all the above samples at room temperature (25° C.) are shown in Table 2.

The room temperature (25 ℃) viscosity change of table 2 embodiment, comparative example

It can be seen from Table 2 that under the same molar ratio, catalysts C3 and C5 prepared with triethyl phosphite and ethynyl cyclohexanol still have a relatively strong catalytic effect in a sealed environment at 25°C. After being immersed in the base silicone oil, the silicone oil quickly loses its fluidity and cannot be further molded. In contrast, the catalysts C1 and C2 further prepared by using the alkynyl phosphite prepared by the method of the present invention can make the silicone oil have an operable time of more than 30 days after being added to the vinyl silicone oil.

In conjunction with Table 1 and Table 2, it can be seen that the alkynyl phosphite compound prepared by the method provided by the invention, when it is applied to the preparation of a platinum complex catalyst, the platinum complex catalyst obtained on the one hand, in It has very low catalytic activity at room temperature, and there is no need to add additional reaction inhibitors during use; on the other hand, it can quickly realize the catalytic curing of silicone rubber at high temperature. This catalyst is beneficial to the storage and transportation of silicone rubber and is suitable for the preparation of one-component silicone rubber.

The above examples are only preferred implementations of the present invention, and are only used to explain the present invention, rather than limit the present invention. Changes, replacements, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention shall belong to the present invention. protection scope of the invention.

Claims (10)

1. A preparation method of alkynyl phosphite ligands is characterized by comprising the following specific steps:

mixing alkynol compound, phosphite ester compound, alkaline catalyst and organic solvent according to a molar ratio of 1:5 to 10:0.15 to 0.3:2 to 10, stirring and heating to 90 to 150 ℃ under the protection of nitrogen to react for 3 to 5 hours until no condensate is generated in a condensing device, washing, filtering, removing impurities, and carrying out vacuum distillation under negative pressure to obtain a product alkynyl phosphite ester ligand shown in a structural formula (1),

wherein R is ₁ 、R ₂ 、R ₃ Is an alkyl group containing 1 to 8C atoms, R ₁ 、R ₂ 、R ₃ May be the same or different.

2. The method of claim 1, wherein the method comprises the following steps:

(1) Adding an alkynol compound, a phosphite ester compound, an alkaline catalyst and an organic solvent into a three-neck flask in proportion, heating to 90-150 ℃ under the conditions of nitrogen protection and stirring, and reacting for 3-5 hours until no condensate is generated in a condensing device to obtain a mixture I;

(2) Adding the mixture I obtained in the step (1) into deionized water, filtering for 3 times, and removing impurities such as a catalyst, a solvent and the like to obtain a mixture II;

(3) And (3) carrying out vacuum distillation on the mixture II obtained in the step (2) under negative pressure for 3-5 hours, and removing residual reactants, deionized water and solvent to obtain a white powder product alkynyl phosphite ester ligand.

3. The method of claim 1, wherein the alkynol compound is an alkane containing both a carbon-carbon triple bond and a hydroxyl group.

4. The method for producing an alkynylphosphite ligand according to claim 2, wherein the alkynol compound is at least one of 2-methyl-3-butyn-2-ol, 1-ethynylcyclohexanol, 3, 5-dimethyl-1-hexyn-3-ol, 3-methyl-1-dodecyn-ol, 3,7, 11-trimethyldodecyn-3-ol, 3, 6-dimethyl-1-heptyn-3-ol, or 3-methyl-1-octyn-3-ol.

5. The method of claim 1, wherein the phosphite compound is a compound of formula (2),

wherein R is ₁ 、R ₂ 、R ₃ Is an alkyl radical containing 1 to 8C atoms, R ₁ 、R ₂ 、R ₃ May be the same or different.

6. The method according to claim 4, wherein the phosphite compound is at least one of trimethyl phosphite, triethyl phosphite, and tributyl phosphite.

7. The method of claim 1, wherein the basic catalyst is NaHCO ₃ 、Na ₂ CO ₃ One of NaOH, KOH or triethylamine.

8. The method of claim 1, wherein the organic solvent is one of n-hexane, n-heptane, cyclohexane, toluene, xylene, petroleum ether or dichloromethane.

9. An alkynyl phosphite ligand prepared by the method of any one of claims 1 to 8.

10. Use of an alkynyl phosphite ligand of claim 9 in a hydrosilylation platinum catalyst.

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