Polyorganosiloxane with regular structure and preparation method thereof

Abstract

The invention discloses polyorganosiloxane with a regular structure and a preparation method of the polyorganosiloxane. According to the invention, tris (pentafluorophenyl) borane is used as a catalyst to catalyze condensation and copolymerization of 1, 1, 3, 3-tetramethyldisiloxane or 1, 1, 1, 3, 5, 7, 7, 7-octamethyltetrasiloxane and alkyl dimethoxy silane or alkyl diethoxy silane, and polyorganosiloxane with a regular structure is prepared at room temperature. According to the preparation method disclosed by the invention, not only can the preparation of polyorganosiloxane which is regular in structure and contains a plurality of alkyl side chains and coexistence of trimethylsiloxy [-OSi (CH3) 3] side chains and the alkyl side chains be realized under mild conditions, but also the formation of polydimethylsiloxane chain segments is avoided, so that the yield of the polyorganosiloxane is improved. And the influence of the formed polydimethylsiloxane on the swelling behavior of the polysiloxane in the use process is reduced. In addition, the preparation method disclosed by the invention is easy to realize accurate control on the polymerization degree of the regular-structure polysiloxane, so that the preparation method has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer compound preparation, and particularly relates to a regular structure polyorganosiloxane and a preparation method thereof. Background Art

[0002] Polyorganosiloxane is a polymer connected by silicon-oxygen bonds (Si-O-Si). Its basic structural unit is siloxane (R2SiO), where R can be various organic groups, such as methyl, phenyl, etc. Depending on the side chain groups, polyorganosiloxane can exhibit different physical and chemical properties. It has important applications in cosmetics, industrial lubricants, electronic appliances, medical health, liquid cooling, thermal conductivity and other fields.

[0003] For the synthesis of polyorganosiloxanes containing alkyl side chains, the currently known method is to start from hydrogen-containing silicone oil and use the hydrosilylation reaction to introduce alkyl side chains. For example, Chinese patents CN104479133A and CN116438502A both disclose starting from hydrogen-containing silicone oil with high silicon hydrogen content, using hydrogen-containing silicone oil and octamethylcyclotetrasiloxane for ring-opening copolymerization under the catalysis of strong acid or strong base; then, by adding alkali to neutralize the acid, filtering and vacuum distillation to obtain hydrogen-containing silicone oil with a certain silicon hydrogen content; finally, alkyl side chain alkyl-modified silicone oil is introduced by catalyzing the hydrosilylation reaction with a platinum catalyst. However, the above methods have the following disadvantages: (1) The reaction needs to be carried out under heating conditions, which consumes a lot of energy. (2) The reaction requires the participation of strong acid or strong base, and the post-treatment is relatively complicated. At the same time, strong acid or strong base catalysis is not selective, and the structure of the synthesized silicone oil is disordered, which easily forms polydimethylsilane. When polydimethylsilane is doped in alkyl-modified silicone oil, it will affect the swelling properties of polyorganosiloxane in plastics, rubber, etc. when used as a cooling fluid. (3) Since the hydrosilylation reaction has a high reactivity to α-olefins, it is very difficult to add cyclic olefins, so it is difficult to introduce cyclic alkanes into the side chain of polysiloxane. (4) In most commercially available hydrogenated silicone oils, there is only one silicon-hydrogen bond on one silicon atom. It is difficult to introduce two alkyl side chains on the same silicon atom, and it is also impossible to simultaneously introduce trimethylsiloxy [-OSi(CH3)3] and alkyl as side chains on the siloxane main chain. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide a regular structure polyorganosiloxane and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention provides a regular structure polyorganosiloxane, whose chemical structure is shown in the following formula (1): (1) Wherein, X and Y are selected from -Si(CH2CH3)3, -Si(C6H 13 )3, -Si(CH3)2Ph, -Si(CH3)[OSi(CH3)3]2 or -Si(CH3)2OSi(CH3)3, X and Y are the same or different; R1 and R2 are selected from C1-C8 alkyl, for example, it can be -CH3, -CH2CH3, -(CH2)2CH3, -CH(CH3)2, -(CH2)3CH3, -CH2CH(CH3)2, -(CH2)4CH3, -CH(CH2)4, -(CH2)5CH3, -CH(CH2)5 or -(CH2)7CH3, R1 and R2 are the same or different; R3 is selected from -CH3 or -OSi(CH3)3; R4 is selected from -CH3 or -CH2CH3; n is selected from an integer from 1 to 50.

[0006] The second aspect of the present invention provides a method for preparing the above-mentioned regular structure polyorganosiloxane, comprising the following steps: S1, adding alkyldimethoxysilane or alkyldiethoxysilane and a catalyst into a solvent, mixing, and obtaining a mixed solution; S2, adding 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane to the mixed solution, stirring and reacting at room temperature to obtain a polyorganosiloxane containing an alkyl side chain and having a methoxy or ethoxy terminal group; Here, there is no strict limit on the amount ratio of the 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane to the alkyldimethoxysilane or alkyldiethoxysilane, as long as the alkyldimethoxysilane or alkyldiethoxysilane is in excess; S3. Add a silicon hydrogen reagent containing a -Si-H bond to the polyorganosiloxane containing alkyl side chains whose terminal groups are methoxy or ethoxy obtained in step S2, and perform a capping reaction at room temperature to obtain a polyorganosiloxane containing alkyl side chains with an alternating regular structure, which is referred to herein as a regular structure polyorganosiloxane.

[0007] Preferably, the amount of the catalyst to 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane is 0.001-0.02:1, more preferably 0.004 - 0.008:1, and particularly preferably 0.006:1.

[0008] Preferably, in step S2, the stirring reaction time is 2 to 6 h.

[0009] Preferably, in step S3, the end-capping reaction time is 2 to 6 h.

[0010] Preferably, the catalyst is tris(pentafluorophenyl)borane.

[0011] Preferably, the solvent is one or a combination of two or more of n-hexane, n-octane, n-heptane, toluene, petroleum ether, and dichloromethane, and n-hexane is more preferably used.

[0012] Preferably, the amount of the silicon hydrogen reagent containing one -Si-H bond is determined according to the reaction feed ratio, and the specific amount is 3 times the difference between the amount of methoxy or ethoxy silane and 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane.

[0013] Preferably, the silicon hydride reagent containing one -Si-H bond is one or a combination of two or more of 1,1,1,3,5,5,5-heptamethyltrisiloxane, triethylsilane, dimethylphenylsilane, trihexylsilane and pentamethyldisiloxane.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) The preparation method of the present invention can not only realize the preparation of polyorganosiloxane with regular structure, containing multiple alkyl side chains and trimethylsiloxy [-OSi(CH3)3] side chains and alkyl side chains under mild conditions, that is, the reaction energy consumption is low; at the same time, because tri(pentafluorophenyl)borane is selected as the catalyst, due to the selectivity of tri(pentafluorophenyl)borane, the formation of polydimethylsiloxane chain segments is avoided, and the influence of the formed long-chain polydimethylsiloxane on the swelling behavior of the polyorganosiloxane during use is reduced.

[0015] (2) The preparation method of the present invention uses tri(pentafluorophenyl)borane as a catalyst to catalyze the condensation copolymerization of 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane with alkyldimethoxysilane or alkyldiethoxysilane, which can not only introduce various types of alkyl groups and realize the introduction of two alkyl side chains on the same silicon atom, but also can introduce trimethylsiloxy [-OSi(CH3)3] and alkyl groups as side chain groups. Therefore, it has broad application prospects.

[0016] (3) The post-processing steps of the preparation method of the present invention are simple, and the catalyst can be removed and recovered by simply adding neutral alumina to adsorb tri(pentafluorophenyl)borane.

[0017] (4) The preparation method of the present invention can easily achieve precise control of the polymerization degree of the regular structure polysiloxane. The polymerization degree of the obtained regular structure polysiloxane can be controlled by simply changing the feed ratio of 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane to alkyldimethoxysilane or alkyldiethoxysilane. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 The general chemical structure formula of a regular structure polyorganosiloxane provided by the present invention; Figure 2 A chemical reaction synthesis route diagram of a regular structure polyorganosiloxane provided by the present invention; Figure 3 is the H NMR spectrum of the polyorganosiloxane obtained in Example 1; Figure 4 is the H NMR spectrum of the polyorganosiloxane obtained in Example 2; Figure 5 This is the H NMR spectrum of the polyorganosiloxane obtained in Example 3; Figure 6 is the H NMR spectrum of the polyorganosiloxane obtained in Example 4; Figure 7 is the H NMR spectrum of the polyorganosiloxane obtained in Example 5; Figure 8 is the H NMR spectrum of the polyorganosiloxane obtained in Example 6; Fig. 9 is the H NMR spectrum of the polyorganosiloxane obtained in Example 7; Fig.10 A schematic diagram of the synthesis route of a regular structure polyorganosiloxane provided by the present invention. DETAILED DESCRIPTION

[0018] The following specific examples are provided to further illustrate the present invention in detail, but are not intended to limit the scope of the present invention.

[0019] The present invention uses tris(pentafluorophenyl)borane to catalyze the condensation copolymerization of 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane and alkyldimethoxysilane or alkyldiethoxysilane to prepare a polyorganosiloxane with a XABB...ABBY regular structure (X, A, B and Y are connected by oxygen) at room temperature. The schematic diagram of the synthesis route is shown below (see Fig.10 ):

[0020] Wherein: the end-capping groups X and Y are selected from -Si(CH2CH3)3, -Si(C6H 13)3, -Si(CH3)2Ph, -Si(CH3)[OSi(CH3)3]2 or -Si(CH3)2OSi(CH3); A is SiR1R2, R1 and R2 are selected from -CH3, -CH2CH3, -(CH2)2CH3, -CH(CH3)2, -(CH2)3CH3, -CH2CH(CH3)2, -(CH2)4CH3, -CH(CH2)4, -(CH2)5CH3, -CH(CH2)5 or -(CH2)7CH, and BB combination is -Si(CH3)3OSi(CH3)3- or -Si(CH3)[OSi(CH3)3]OSi(CH3)[OSi(CH3)3]-.

[0021] The present invention provides a method for preparing a regular structure polyorganosiloxane, and the specific chemical reaction synthesis route is as follows (see Figure 2 ):

[0022] Wherein, X and Y are selected from -Si(CH2CH3)3, -Si(C6H 13 )3, -Si(CH3)2Ph, -Si(CH3)[OSi(CH3)3]2 or -Si(CH3)2OSi(CH3)3, X and Y are the same or different; R1 and R2 are selected from C1-C8 alkyl, for example, can be -CH3, -CH2CH3, -(CH2)2CH3, -CH(CH3)2, -(CH2)3CH3, -CH2CH(CH3)2, -(CH2)4CH3, -CH(CH2)4, -(CH2)5CH3, -CH(CH2)5 or -(CH2)7CH3, R1 and R2 are the same or different; R3 is selected from -CH3 or -OSi(CH3)3; R4 is selected from -CH3 or -CH2CH3; n is an integer from 1 to 50. Example 1 21.8 g of octylmethyldimethoxysilane, 0.4 g of tri(pentafluorophenyl)borane and 50 mL of n-hexane were mixed and added to a 250 mL three-necked flask. A mixed solution of 50 mL of n-hexane and 10.1 g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise at a stirring speed of 300 r / min. After the addition was completed, the reaction was continued for 3 h. Then, 9.5 g of pentamethyldisiloxane was slowly added and the reaction was continued for 3 h. After the reaction was completed, 5 g of neutral alumina was added. The product was filtered and distilled under reduced pressure to obtain the product with a yield of 92.4%. The obtained product was characterized by an AVACNE III 400 (400MHz) nuclear magnetic resonance spectrometer (using deuterated chloroform (CDCl3) without TMS as the solvent) to obtain 1 H NMR spectrum Figure 3 As shown by Figure 3 The test results show that the product obtained in this example is a polyorganosiloxane with a regular alternating structure, and the chemical structure is:

[0023] Where R1 is -C8H 17 , R2 and R3 are -CH3, X and Y are -Si(CH3)2OSi(CH3)3, and the average value of n is 3.

[0024] Example 2 25.5 g of diisobutyldimethoxysilane, 0.4 g of tris(pentafluorophenyl)borane and 50 mL of n-hexane were mixed and added to a 250 mL three-necked flask. A mixed solution of 50 mL of n-hexane and 13.4 g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise at a stirring speed of 300 r / min. After the addition was completed, the reaction was continued for 3 h. Then, 17.5 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane was slowly added and the reaction was continued for 3 h. After the reaction was completed, 5 g of neutral alumina was added, and the product was obtained by filtration and reduced pressure distillation with a yield of 91.2%. The obtained product was characterized and obtained 1 H NMR spectrum Figure 4 As shown, through Figure 4 The results show that the product obtained in this example is a polyorganosiloxane with a regular alternating structure, and the chemical structure is:

[0025] Among them, R1 and R2 are both -CH2CH(CH3)2, R3 is -CH3, X and Y are both -Si(CH3)[OSi(CH3)3]2, and the average value of n is 3.

[0026] Example 3 22.5 g of diisobutyldimethoxysilane, 0.4 g of tri(pentafluorophenyl)borane and 50 mL of n-hexane were mixed and added to a 250 mL three-necked flask. A mixed solution of 50 mL of n-hexane and 13.4 g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise at a stirring speed of 300 r / min. After the addition was completed, the reaction was continued for 3 h. Then, 16 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane was slowly added and the reaction was continued for 3 h. After the reaction was completed, 5 g of neutral alumina was added, and the product was obtained by filtration and reduced pressure distillation with a yield of 89.7%. The obtained product was characterized and obtained 1 H NMR spectrum Figure 5 As shown, through Figure 5The results show that the product obtained in this example is a polyorganosiloxane with a regular alternating structure, and the chemical structure is:

[0027] Among them, R1 and R2 are both -CH2CH(CH3)2, R3 is -CH3, X and Y are both -Si(CH3)[OSi(CH3)3]2, and the average value of n is 4.

[0028] Example 4 23.5 g of cyclohexylmethyldimethoxysilane, 0.4 g of tri(pentafluorophenyl)borane and 50 mL of n-hexane were mixed and added to a 250 mL three-necked flask. A mixed solution of 50 mL of n-octane and 13.4 g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise at a stirring speed of 300 r / min. After the addition was completed, the reaction was continued for 3 h. Then, 20 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane was slowly added and the reaction was continued for 3 h. After the reaction was completed, 5 g of neutral alumina was added, and the product was obtained by filtration and reduced pressure distillation with a yield of 90.1%. The obtained product was characterized and obtained 1 H NMR spectrum Figure 6 As shown, through Figure 6 The results show that the product obtained in this example is a polyorganosiloxane with a regular alternating structure, and the chemical structure is: ; Among them, R1, R3 are -CH3, R2 is -C6H 11 , X and Y are both -Si(CH3)[OSi(CH3)3]2, and the average value of n is 4.

[0029] Example 5 22.6 g of cyclohexylmethyldimethoxysilane, 0.4 g of tris(pentafluorophenyl)borane and 50 mL of n-hexane were mixed and added to a 250 mL three-necked flask. A mixed solution of 50 mL of n-hexane and 13.4 g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise at a stirring speed of 300 r / min. After the addition was completed, the reaction was continued for 3 h. After 3 h, 18 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane was slowly added and the reaction was continued for 3 h. After the reaction was completed, 5 g of neutral alumina was added, and the product was obtained by filtration and reduced pressure distillation with a yield of 92.3%. The obtained product was characterized and obtained 1 H NMR spectrum Figure 7 As shown, through Figure 7 The results show that the product obtained in this example is a polyorganosiloxane with a regular alternating structure, and the chemical structure is: ; Among them, R1, R3 are -CH3, R2 is -C6H 11 , X and Y are both -Si(CH3)[OSi(CH3)3]2, and the average value of n is 3.

[0030] Example 6 45.2 g of cyclohexylmethyldimethoxysilane, 0.3 g of tri(pentafluorophenyl)borane and 50 mL of n-hexane were mixed and added to a 500 mL three-necked flask. A mixed solution of 50 mL of petroleum ether and 26.8 g of 1,1,3,3-tetramethyldisiloxane was slowly added dropwise at a stirring speed of 300 r / min. After the addition was completed, the reaction was continued for 3 h. Then, 18 g of triethylsilane was slowly added and the reaction was continued for 3 h. After the reaction was completed, 5 g of neutral alumina was added, and the product was obtained by filtration and vacuum distillation with a yield of 91.6%. The obtained product was characterized and obtained 1 H NMR spectrum Figure 8 As shown, through Figure 8 The results show that the product obtained in this example is a polyorganosiloxane with a regular alternating structure, and its chemical structure is:

[0031] Among them, R1, R3 are -CH3, R2 is -C6H 11 , X and Y are both -Si(CH2CH3)3, and the average value of n is 6.

[0032] Example 7 28.2 g of cyclohexylmethyldimethoxysilane, 0.3 g of tri(pentafluorophenyl)borane and 50 mL of n-octane were mixed and added to a 500 mL three-necked flask. A mixed solution of 50 mL of n-hexane and 28.3 g of 1,1,1,3,5,7,7,7-octamethyltetrasiloxane was slowly added dropwise at a stirring speed of 300 r / min. After the addition was completed, the reaction was continued for 3 h. After 3 h, 15 g of triethylsilane was slowly added and the reaction was continued for 3 h. After the reaction was completed, 5 g of neutral alumina was added, and the product was obtained by filtration and reduced pressure distillation with a yield of 96.5%. The obtained product was characterized and obtained 1 H NMR spectrum Fig. 9 As shown, through Fig. 9 The results show that the product obtained in this example is a polyorganosiloxane with a regular alternating structure, and its chemical structure is:

[0033] Where R1 is -CH3 and R2 is -C6H 11, R3 is -OSi(CH3)3, X and Y are both -Si(CH2CH3)3, and the average value of n is 2.

[0034] The above description is only a specific embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent process or equivalent reagent replacement using the contents described in the specification of the present invention is also included in the protection scope of the patent of the present invention.

Claims

1. A regular structure polyorganosiloxane, characterized in that: The chemical structure of the regular structure polyorganosiloxane is shown in the following formula (1): （1） Wherein: X and Y are selected from -Si(CH2CH3)3, -Si(C6H 13 )3, -Si(CH3)2Ph, -Si(CH3)[OSi(CH3)3]2 and -Si(CH3)2OSi(CH3)3, X and Y are the same or different; R1 and R2 are selected from C1-C8 alkyl, R1 and R2 are the same or different; R3 is selected from -CH3 or -OSi(CH3)3; n is selected from an integer from 1 to 50.

2. A method for preparing a regular structure polyorganosiloxane as claimed in claim 1, characterized in that: The following steps are involved: S1, adding alkyldimethoxysilane or alkyldiethoxysilane and a catalyst into a solvent, mixing, and obtaining a mixed solution; S2, adding 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octamethyltetrasiloxane to the mixed solution, stirring and reacting at room temperature to obtain a polyorganosiloxane having an alkyl side chain and a methoxy or ethoxy terminal group; S3, adding a silicon hydrogen reagent containing one -Si-H bond to the polyorganosiloxane containing an alkyl side chain and having a methoxy or ethoxy terminal group obtained in step S2, and performing a capping reaction at room temperature to obtain a polyorganosiloxane with a regular structure.

3. The method for preparing the regular structure polyorganosiloxane according to claim 2, characterized in that: The catalyst is mixed with 1,1,3,3-tetramethyldisiloxane or 1,1,1,3,5,7,7,7-octadecane The amount of methyltetrasiloxane is 0.001-0.02:

1.

4. The method for preparing a regular structure polyorganosiloxane according to claim 2, characterized in that: In step S2, the stirring reaction time is 2 to 6 h.

5. The method for preparing the regular structure polyorganosiloxane according to claim 2, characterized in that: In step S3, the end-capping reaction time is 2 to 6 h.

6. The method for preparing a regular structure polyorganosiloxane according to claim 4, characterized in that: The catalyst is tris(pentafluorophenyl)borane.

7. The method for preparing a regular structure polyorganosiloxane according to claim 2, characterized in that: The solvent is one or a combination of two or more of n-hexane, n-octane, n-heptane, toluene, petroleum ether and dichloromethane.

8. The method for preparing the regular structure polyorganosiloxane according to claim 2, characterized in that: The silicon hydride reagent containing one -Si-H bond is one or a combination of two or more of 1,1,1,3,5,5,5-heptamethyltrisiloxane, triethylsilane, dimethylphenylsilane, trihexylsilane and pentamethyldisiloxane.

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