CN111072716B - Preparation method of tetramethyl tetravinylcyclotetrasiloxane - Google Patents
Preparation method of tetramethyl tetravinylcyclotetrasiloxane Download PDFInfo
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- VMAWODUEPLAHOE-UHFFFAOYSA-N 2,4,6,8-tetrakis(ethenyl)-2,4,6,8-tetramethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane Chemical compound C=C[Si]1(C)O[Si](C)(C=C)O[Si](C)(C=C)O[Si](C)(C=C)O1 VMAWODUEPLAHOE-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 238000002360 preparation method Methods 0.000 title claims abstract description 9
- 239000000413 hydrolysate Substances 0.000 claims abstract description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 28
- YLJJAVFOBDSYAN-UHFFFAOYSA-N dichloro-ethenyl-methylsilane Chemical compound C[Si](Cl)(Cl)C=C YLJJAVFOBDSYAN-UHFFFAOYSA-N 0.000 claims abstract description 25
- 238000006243 chemical reaction Methods 0.000 claims abstract description 22
- 239000002904 solvent Substances 0.000 claims abstract description 16
- 239000004094 surface-active agent Substances 0.000 claims abstract description 14
- 239000000203 mixture Substances 0.000 claims abstract description 13
- 239000002253 acid Substances 0.000 claims abstract description 12
- 239000012266 salt solution Substances 0.000 claims abstract description 11
- 238000007363 ring formation reaction Methods 0.000 claims abstract description 9
- 238000005406 washing Methods 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 5
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 4
- 238000001816 cooling Methods 0.000 claims abstract description 4
- 238000005336 cracking Methods 0.000 claims description 18
- 239000000243 solution Substances 0.000 claims description 18
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 16
- -1 octyl phenyl Chemical group 0.000 claims description 15
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 238000009835 boiling Methods 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 12
- 229940051841 polyoxyethylene ether Drugs 0.000 claims description 10
- 229920000056 polyoxyethylene ether Polymers 0.000 claims description 10
- 238000005292 vacuum distillation Methods 0.000 claims description 9
- 239000011780 sodium chloride Substances 0.000 claims description 8
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims description 4
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 4
- 239000000194 fatty acid Substances 0.000 claims description 4
- 229930195729 fatty acid Natural products 0.000 claims description 4
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 claims description 4
- JHJLBTNAGRQEKS-UHFFFAOYSA-M sodium bromide Chemical compound [Na+].[Br-] JHJLBTNAGRQEKS-UHFFFAOYSA-M 0.000 claims description 4
- 229920001214 Polysorbate 60 Polymers 0.000 claims description 2
- 239000001103 potassium chloride Substances 0.000 claims description 2
- 235000011164 potassium chloride Nutrition 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- DAJSVUQLFFJUSX-UHFFFAOYSA-M sodium;dodecane-1-sulfonate Chemical compound [Na+].CCCCCCCCCCCCS([O-])(=O)=O DAJSVUQLFFJUSX-UHFFFAOYSA-M 0.000 claims description 2
- 239000000047 product Substances 0.000 abstract description 17
- 238000006460 hydrolysis reaction Methods 0.000 abstract description 14
- 238000004062 sedimentation Methods 0.000 abstract description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 18
- 239000003921 oil Substances 0.000 description 17
- JMTARFYECDNZGS-UHFFFAOYSA-N ethenyl-dihydroxy-methylsilane Chemical compound C[Si](O)(O)C=C JMTARFYECDNZGS-UHFFFAOYSA-N 0.000 description 13
- 230000007062 hydrolysis Effects 0.000 description 10
- 238000000926 separation method Methods 0.000 description 10
- 238000003756 stirring Methods 0.000 description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- SCPYDCQAZCOKTP-UHFFFAOYSA-N silanol Chemical compound [SiH3]O SCPYDCQAZCOKTP-UHFFFAOYSA-N 0.000 description 6
- 108010009736 Protein Hydrolysates Proteins 0.000 description 5
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 5
- 239000012267 brine Substances 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 238000004817 gas chromatography Methods 0.000 description 5
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
- 238000006068 polycondensation reaction Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 230000036632 reaction speed Effects 0.000 description 3
- GPRLSGONYQIRFK-MNYXATJNSA-N triton Chemical compound [3H+] GPRLSGONYQIRFK-MNYXATJNSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000010907 mechanical stirring Methods 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 238000012643 polycondensation polymerization Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 229920000136 polysorbate Polymers 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- ZBXBDQPVXIIXJS-UHFFFAOYSA-N 2,4,6,8,10-pentakis(ethenyl)-2,4,6,8,10-pentamethyl-1,3,5,7,9,2,4,6,8,10-pentaoxapentasilecane Chemical compound C=C[Si]1(C)O[Si](C)(C=C)O[Si](C)(C=C)O[Si](C)(C=C)O[Si](C)(C=C)O1 ZBXBDQPVXIIXJS-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 210000003298 dental enamel Anatomy 0.000 description 1
- PNECSTWRDNQOLT-UHFFFAOYSA-N dichloro-ethyl-methylsilane Chemical compound CC[Si](C)(Cl)Cl PNECSTWRDNQOLT-UHFFFAOYSA-N 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- HIHIPCDUFKZOSL-UHFFFAOYSA-N ethenyl(methyl)silicon Chemical compound C[Si]C=C HIHIPCDUFKZOSL-UHFFFAOYSA-N 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000005194 fractionation Methods 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229950008882 polysorbate Drugs 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007142 ring opening reaction Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000013341 scale-up Methods 0.000 description 1
- 150000004819 silanols Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/21—Cyclic compounds having at least one ring containing silicon, but no carbon in the ring
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Silicon Polymers (AREA)
Abstract
The invention provides a preparation method of tetramethyl tetravinylcyclotetrasiloxane. The preparation method comprises the following steps: (1) adding methylvinyl dichlorosilane into a low-temperature solvent system, reacting at a low temperature for a period of time, then heating to a high temperature condition for cyclization reaction, and after the reaction is finished, cooling and separating the reaction liquid to obtain an acid water layer and an oil layer; wherein the solvent system comprises water and a surfactant; (2) adding a salt solution into the oil layer for washing and settling, adjusting the pH value of the mixture, and separating out hydrolysate; (3) and carrying out reduced pressure rectification on the hydrolysate to obtain fraction containing tetramethyl tetravinylcyclotetrasiloxane. The method adopts a closed-loop control process: low-temperature hydrolysis reaction, adding a surfactant and acid high-temperature cyclization; and the salt solution is further assisted in washing and sedimentation, so that the purposes of improving the yield of the ring body V4 and improving the product quality of the ring body V4 are achieved.
Description
Technical Field
The invention belongs to the field of organosilicon preparation, and particularly relates to a preparation method of tetramethyl tetravinylcyclotetrasiloxane.
Background
Tetramethyltetravinylcyclotetrasiloxane (V4) is generally prepared by the following method: hydrolyzing methyl vinyl dichlorosilane with water under certain conditions (water, 6mol/L hydrochloric acid, saturated concentrated hydrochloric acid and solvent) to obtain a mixture of a ring body and a linear body, namely hydrolysate; after layered washing, adding catalysts (potassium hydroxide and tetramethylammonium hydroxide) into the hydrolysate for cracking under the conditions of high temperature (160-.
How to effectively promote the ring body share generated in the hydrolysis process and reduce the cracking quantity so as to achieve the purposes of saving energy, improving yield and reducing cost becomes a technical problem to be solved urgently. In the cracking process, besides the ring body, other impurities are generated, and the quality of the product is influenced by the additionally generated impurities. For example, the cracked material has a large proportion of V3, and even after rectification, the finished product contains a certain proportion of V3. Due to the large angle of V3 in the molecule, V3 can be added into the polymer through ring opening in advance when the polymer is applied in downstream, so that the distribution of vinyl groups is not uniform, and the quality of the final product is influenced. And V3 has poor stability under acidic conditions, and can be changed into silanol again after a period of time, and the silanol is polymerized again into V4 and other macrocyclic rings with good stability. How to improve the quality of the V4 product is also a technical problem to be solved.
Disclosure of Invention
The invention provides a preparation method of tetramethyl tetravinylcyclotetrasiloxane, which comprises the following steps:
(1) adding methylvinyl dichlorosilane into a low-temperature solvent system, reacting at a low temperature for a period of time after the addition is finished, then heating to a high temperature condition for cyclization reaction, and cooling and separating the reaction liquid after the reaction is finished to obtain an acid water layer and an oil layer;
wherein, the solvent system comprises water and a surfactant, and the surfactant is selected from at least one of octyl phenyl polyoxyethylene ether, sorbitan fatty acid ester (also called span), polyoxyethylene sorbitan fatty acid ester (also called polysorbate, tween) and sodium dodecyl sulfonate;
(2) adding a salt solution into the oil layer for washing and settling, adjusting the pH value of the mixture, and separating out hydrolysate;
(3) and carrying out reduced pressure rectification on the hydrolysate to obtain fraction containing tetramethyl tetravinylcyclotetrasiloxane.
According to an embodiment of the invention, in step (1), the mass ratio of water to methylvinyldichlorosilane is (2-3):1, for example (2.3-2.8):1, exemplary 8:3, 2.67: 1.
According to an embodiment of the present invention, in the step (1), the surfactant is preferably octylphenyl polyoxyethylene ether. Wherein the concentration of the surfactant in the low temperature solvent system is 200-1000ppm, such as 400-800ppm, exemplary 500ppm, 750 ppm. The addition of the surfactant can effectively improve the reaction speed of the methyl vinyl dichlorosilane and water, so that a large amount of methyl vinyl silanediol is generated; on the other hand, the generated methyl vinyl silanediol can be better dispersed, and the possibility of condensation in advance is reduced.
According to an embodiment of the invention, in step (1), said low temperature is at a temperature of 10-25 ℃, for example 14-22 ℃, and for example 15-20 ℃, in order to reduce the rate of the silanol condensation reaction and thus the amount of linear bodies formed.
According to the embodiment of the invention, in the step (1), the dropping speed of the methyl vinyl dichlorosilane is not particularly limited, and the methyl vinyl dichlorosilane can be stirred while being dropped, on one hand, the added methyl vinyl dichlorosilane is completely mixed with a solvent system, so that the advanced polymerization of silanol is reduced; on the other hand, the temperature of the solvent system is stably maintained at a low temperature, and the temperature of the solvent system is not changed by adding the methyl vinyl dichlorosilane. For example, the dropping rate can be from 0.5 to 1.5g/min, such as from 0.75 to 1.2g/min, with 0.83g/min being exemplary. Alternatively, methylvinyldichlorosilane is added at the same temperature as the solvent system. In the industrial production, the temperature of the system can be controlled by introducing a cooling medium, and the addition amount of the methyl vinyl dichlorosilane is not particularly limited and can be at least 50 kg/h, for example 100 kg/h.
According to an embodiment of the invention, in step (1), the low temperature reaction is carried out for a period of time ranging from 1 to 5 hours, such as from 2 to 4 hours, illustratively 2 hours, 4 hours.
According to the embodiment of the invention, in the step (1), the low-temperature reaction is a hydrolysis process of methyl vinyl dichlorosilane, hydrochloric acid and methyl vinyl silanediol are generated after the hydrolysis, the generated hydrochloric acid enables the concentration of hydrochloric acid in the system to be about 6mol/L, and conditions are provided for the continuous polycondensation and dehydration of methyl vinyl silanediol to generate ring bodies V4 or V5.
According to an embodiment of the invention, in step (1), the temperature of the cyclisation reaction is between 50 and 60 ℃, for example between 53 and 58 ℃, exemplarily 55 ℃. Further, the cyclization reaction time is 3 to 5 hours, such as 3.2 to 4 hours, illustratively 3.5 hours, 4 hours. If the temperature is too low, the condensation polymerization of the methyl vinyl silanediol is incomplete, the yield of hydrolysate is influenced, and finally the overall yield is low; the hydrolysate contains low-chain (silicon chain is 3-5) polymethylvinylsiloxane, and the end of the low-chain (silicon chain is 3-5) polymethylvinylsiloxane has poor stability in the hydrolysate, so that the low-chain (silicon chain is continuously polymerized at room temperature to generate moisture, the hydrolysate is turbid, and the moisture is brought into a V4 finished product during rectification to influence the quality of the finished product. Under the condition of 50-60 ℃, the methylvinyl silanediol can fully react, and meanwhile, the low-chain polymethylvinylsiloxane can be condensed into a ring body or polymerized into stable linear polymethylvinylsiloxane (more than 10 silicon units), so that the generation of moisture is reduced.
According to an embodiment of the present invention, in step (1), the separation may be performed by a known procedure in the art, for example, separation using a separatory funnel.
According to an embodiment of the present invention, in the step (2), the salt solution may be at least one selected from a sodium chloride solution, a potassium chloride solution, a sodium bromide solution, a potassium bromide solution, and the like, and is preferably a sodium chloride solution. Further, the salt solution had a density greater than that of Ring V4 (tetramethyltetravinylcyclotetrasiloxane) (density about 0.9875 g/ml); for example, the sodium chloride solution may have a concentration of 15-25%, such as 18-22%, illustratively 20% (density of about 1.14779 g/ml).
According to an embodiment of the present invention, in the step (2), the pH adjustment may be achieved by adding a base to the mixture, for example, the base is at least one of sodium hydroxide and potassium hydroxide, preferably sodium hydroxide; further, the pH is adjusted to 8-9, e.g. 8.2-8.7.
And (2) adopting a salt solution to wash and settle the oil layer obtained in the step (1), and utilizing the density difference between the salt solution and the ring body to avoid the condition that oil-in-water or water-in-oil is easy to form when the oil layer is washed by pure water in the prior art, thereby improving the yield of the ring body, accelerating the settling and layering speed and saving the production time.
According to an embodiment of the present invention, in step (2), the separation may be performed by a known operation in the art, for example, separation using a separatory funnel, and the hydrolysate and brine are separated. The brine can be recycled.
According to an embodiment of the present invention, in the step (3), before the vacuum distillation, the hydrolysate is optionally dried by various drying means known in the art, such as anhydrous sodium sulfate.
According to the embodiment of the invention, in the step (3), the vacuum distillation can adopt the operation known in the art, for example, direct distillation can be adopted, and the fraction with the negative pressure of 730-745 mm Hg (for example 735 mm Hg), the boiling point of 117-123 ℃ (for example 119-121 ℃) is collected to obtain V4; the fractional vacuum distillation method can also be adopted to collect the fraction with the negative pressure of 730-745 mm Hg and the boiling point of 150-180 ℃ to obtain the total methylvinylcyclosiloxane, then the total methylvinylcyclosiloxane is further fractionated to collect the fraction with the negative pressure of 730-745 mm Hg (such as 735 mm Hg) and the boiling point of 117-123 ℃ (such as 119-121 ℃) to obtain V4, and the operation method can obtain high-quality V4 (the content is more than or equal to 95%). In order to monitor the requirements of the process conditions and effects, a fractional vacuum distillation method can be adopted, wherein the cyclic V5 (pentamethylpentavinylcyclopentasiloxane) is distilled out as much as possible, and the fraction with a higher temperature range, such as the fraction with a boiling point of 150-180 ℃, such as the fraction with a boiling point of 155-170 ℃ is collected.
According to an embodiment of the present invention, the preparation method further comprises step (4): and collecting residual liquid and/or front fraction after vacuum distillation, and obtaining a cracking mixed ring body after the residual liquid and/or the front fraction are cracked again. Further, the cracking mixed ring body is rectified to obtain ring body V4. If a fractionation step is present, the fractionated front cut can also be combined with the raffinate and then cracked again, either separately, to give a cracked mixed ring for rectification to give ring V4.
In the present invention, the "front cut" is a cut having a boiling point lower than that of the objective cut; the "raffinate" is the residue which has a boiling point higher than that of the target fraction after the target fraction is obtained.
According to an exemplary embodiment of the present invention, a method for preparing tetramethyltetravinylcyclotetrasiloxane comprises the steps of:
(1) adding methyl vinyl dichlorosilane into a solvent system at 15-20 ℃, after the addition is finished, carrying out hydrolysis reaction at 15-20 ℃ for 1-5 hours to generate hydrochloric acid, then heating to 50-60 ℃ for carrying out cyclization reaction for 3-4 hours, and after the reaction is finished, cooling and separating reaction liquid to obtain an acid water layer and an oil layer;
wherein the solvent system comprises water and octyl phenyl polyoxyethylene ether, the mass ratio of the water to the methyl vinyl dichlorosilane is (2-3) to 1, and the concentration of the octyl phenyl polyoxyethylene ether in the solvent system is 200-1000 ppm;
(2) adding sodium chloride aqueous solution into the oil layer for washing and settling, adding alkali to adjust the pH value of the mixture to be between 8 and 9, and separating out hydrolysate;
(3) carrying out reduced pressure rectification on the hydrolysate to obtain fraction containing tetramethyl tetravinylcyclotetrasiloxane;
optionally further comprising: (4) and collecting the residual liquid and/or the front fraction after vacuum rectification, cracking the front fraction and/or the residual liquid again to obtain a cracking mixed ring body, and rectifying the cracking mixed ring body to obtain the ring body V4.
The principle of the method of the invention is as follows:
the low-temperature hydrolysis process of the methyl vinyl dichlorosilane generates a large amount of methyl vinyl silanediol, and a surfactant (such as octyl phenyl polyoxyethylene ether) in the system can improve the dispersion degree of the methyl vinyl silanediol in the system, greatly reduce the contact probability among the methyl vinyl silanediol, and reduce the possibility of generating a linear body by condensation polymerization in the hydrolysis process of the silanol. Then a large amount of methyl vinyl silicon glycol is subjected to polycondensation dehydration under the conditions (acid and high temperature) of the invention to generate a ring body V4 or V5 with a stable structure.
The invention has the beneficial effects that:
in order to control that the methylvinyl silanediol can keep the monomer state before condensation, the method adopts a closed-loop control process: low-temperature hydrolysis reaction, adding surfactant (such as octyl phenyl polyoxyethylene ether), and acid high-temperature cyclization. And the salt solution is further assisted to wash and settle, so that the purposes of improving the yield of the ring body V4 and improving the product quality of the ring body V4 are achieved.
Specifically, through the low-temperature hydrolysis reaction and the coordination of a surfactant (such as octyl phenyl polyoxyethylene ether), methyl vinyl silanediol is firstly generated, the reaction speed of hydrolyzing methyl vinyl dichlorosilane to generate the methyl vinyl silanediol is obviously higher than the reaction speed of polycondensation between silanols, the silanol is prevented from being polycondensed into siloxane linear bodies in advance, and the number of generated ring bodies is far larger than that of the linear bodies. Then a large amount of methyl vinyl silanediol is condensed and dehydrated under the acidic high-temperature condition to generate a ring body V4 with a stable structure. The hydrolysate separation process adopts brine sedimentation, which not only can accelerate the separation process, but also can improve the yield of the ring body V4. Carrying out vacuum rectification on the separated hydrolysate, and collecting to obtain a V4 product (superior product) with the content of more than or equal to 95%; residual liquid after vacuum distillation is accumulated and collected, and then is cracked to obtain cracked mixed ring bodies, and the mixed ring bodies are distilled to obtain V4 products (qualified products) with the content of more than or equal to 85 percent.
According to the method, the ratio of the ring body generated in the hydrolysis process to the linear body is 7-9:1 in percentage by mass, which is higher than the ratio of the ring body generated in the general operation of the prior art to the linear body which is 0.9-1.7: 1; and in the hydrolysate, the content of V3 is almost 0; the hydrolysate is subjected to vacuum rectification to obtain high-content cyclic V4, so that the amount of later-stage cracking is greatly reduced, the cracking amount can be reduced by 70-80%, and the energy consumption in the V4 production process is effectively reduced. Meanwhile, after the hydrolysate is directly subjected to reduced pressure rectification, the V4 finished product contains V4 with a stable structure and a small amount of V5, does not contain V3 with an unstable structure, and has a vinyl distribution close to a theoretical value in downstream application, so that the quality of downstream products is improved.
In addition, the method is suitable for industrial amplification production.
Detailed Description
The technical solution of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the techniques realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.
Methylvinyldichlorosilane: supplied by Elkem, the content of methyl vinyl dichlorosilane is 99.3%, and the content of methyl ethyl dichlorosilane is less than or equal to 0.5%.
Triton TX-100 is the trade name octylphenyl polyoxyethylene ether.
The total content of cyclo body V4 in the hydrolysis solution in the examples and comparative examples was calculated from the following equation:
the total content of the loop bodies V4 in the hydrolysate (mass of collected fraction/mass of hydrolysate) x mass percent of the loop bodies V4 in the collected fraction.
Example 1
Adding 800g of water and 500ppm of triton TX-100 into a 2000ml three-neck flask with a mechanical stirrer, starting stirring, reducing the temperature to 15 ℃ by using a cold salt bath, beginning to dropwise add 300g of methyl vinyl dichlorosilane, controlling the reaction temperature to be between 15 and 20 ℃, after finishing dripping for 6 hours, continuing to react for 2 hours at the temperature of between 15 and 20 ℃, controlling the concentration of hydrochloric acid generated after hydrolysis to be about 6mol/L, removing the cold salt bath, changing to an electric heating jacket, heating to 58 ℃ under stirring, controlling the reaction temperature to be between 50 and 60 ℃, and reducing the temperature after reacting for 4 hours. The reaction solution was poured into a separatory funnel, and an acid aqueous layer and an oil layer were separated.
Pouring the oil layer into a reaction bottle, adding 100g of 20 wt% sodium chloride aqueous solution, stirring, dropwise adding 20 wt% sodium hydroxide solution until the pH value reaches 9, pouring into a separating funnel, separating out the upper oil phase, and drying with anhydrous sodium sulfate to obtain 176.1g of hydrolysate. The hydrolysate was subjected to rectification under reduced pressure, and the fraction boiling at 155 ℃ onward (at 745 mm Hg) was collected to give 158.2g of fraction, which was sampled for gas chromatography.
The contents of the various substances in the fractions are shown in the following table:
| composition (A) | V3 | V4 | V5 |
| Content (%) | 0 | 83.94 | 14.65 |
The total content of the loop body V4 in the hydrolysate is calculated to be 75.4%.
Example 2 Scale-up production
To 3m 3 2000 kg of water and 1.5 kg of triton TX-10 are added into an enamel reaction kettle, a stirring and quenching water valve is opened, the temperature is reduced to 15 ℃, a methyl vinyl dichlorosilane feeding valve is opened, the feeding speed is controlled to be 100 kg/h, the hydrolysis temperature is controlled to be 15-20 ℃ (the temperature is reduced by adjusting the feeding speed and cold water), the feeding is stopped when 750 kg of water is stopped, and after the reaction is continued for 4 hours, the concentration of hydrochloric acid generated after hydrolysis is about 6 mol/L. And (3) closing the quenching water, raising the temperature to 58 ℃ through steam, reacting for 4 hours, opening a kettle bottom valve, slowly discharging lower-layer acid water, observing the water layer phenomenon, closing a drain valve when an oil-water separation layer appears, standing for half an hour, and slowly discharging residual acid water. Adding 250 kg of 20 wt% brine into a reaction kettle, starting stirring, neutralizing with an alkali liquor (20 wt%) until the pH value is 8-9, putting the materials into a settling kettle, standing for 2 hours, observing the oil-water separation phenomenon, if the separation is incomplete, continuously standing and layering until the separation is complete to obtain 450 kg of hydrolysate, and recycling the brine. 450 kg of hydrolysate was subjected to negative pressure rectification and fractions before 170 ℃ (735 mm Hg) were collected to give 404.3 kg of loop mixture, which was sampled for gas chromatography.
The contents of the various substances in the fractions are shown in the following table:
| composition (I) | V3 | V4 | V5 |
| Content (%) | 0 | 83.75 | 15.00 |
The total content of the loop body V4 in the hydrolysate is calculated to be 75.2 percent.
And (3) subsequent operation: discharging residual liquid in the rectifying still, putting the residual liquid into a linear storage tank, concentrating the residual liquid into a certain amount (10-15 tons) for cracking reaction, preparing mixed ring bodies (the cracking yield is 95 percent, namely 38 kilograms of mixed ring bodies can be obtained from 40 kilograms of still residues), and rectifying the mixed ring bodies to obtain V4. The corresponding front cut (V3) and bottoms (V5) can then be cracked again.
In actual production, the hydrolysate can be subjected to vacuum rectification to obtain V4 with the content of more than or equal to 95 percent, and the V4 is used as a superior product and used as a raw material for producing high-end products.
And the mixed ring body obtained after cracking the collected residual liquid is rectified to obtain a fraction with the V4 content of more than or equal to 85 percent, the fraction is used as a qualified product and is used as a raw material for producing general products, and the front fraction and the residual liquid obtained in the rectifying step can be collected and then returned to the cracking kettle for cracking again.
Comparative example 1
In a 2000ml three-necked flask with mechanical stirring, 800g of water was added, stirring was started, 300g of methylvinyldichlorosilane was started to be dropped, the reaction temperature was observed (up to 45 ℃), the dropping speed was controlled, and after dropping was completed within 6 hours, the reaction solution was poured into a separatory funnel, and an acid water layer and an oil layer were separated. Pouring the oil layer into a reaction bottle, adding 100g of 20 wt% sodium chloride aqueous solution, stirring, dropwise adding 20 wt% sodium hydroxide solution until the pH value reaches 9, pouring into a separating funnel, separating out the upper oil phase, and drying with anhydrous sodium sulfate to obtain 175.6g of hydrolysate. And (3) performing reduced pressure rectification on the hydrolysate, collecting fractions with boiling points of 155 ℃ or higher (745 mm Hg) to obtain 98.3g fractions, and sampling for gas chromatography analysis.
The contents of the various substances in the fractions are shown in the following table:
| composition (I) | V3 | V4 | V5 |
| Content (%) | 1.33 | 81.32 | 16.01 |
The total content of the loop body V4 in the hydrolysate is calculated to be 45.5 percent.
Comparative example 2
In 2000ml three-necked flask with mechanical stirring, 800g of 6mol/L hydrochloric acid was added, stirring was started, 300g of methyl vinyl dichlorosilane was added dropwise, the reaction temperature was observed (up to 57 ℃), the dropping speed was controlled, and after 8 hours of dropping, the reaction solution was poured into a separatory funnel, and an acid water layer and an oil layer were separated. Pouring the oil layer into a reaction bottle, adding 100g of 20 wt% sodium chloride aqueous solution, stirring, dropwise adding 20 wt% sodium hydroxide solution until the pH value reaches 9, pouring into a separating funnel, separating an upper oil phase, and drying with anhydrous sodium sulfate to obtain 179g of hydrolysate. The hydrolysate was subjected to rectification under reduced pressure, and the fraction boiling at 155 ℃ onward (745 mm Hg) was collected to give 114.8g of fraction, which was sampled for gas chromatography.
The contents of the various substances in the fractions are shown in the following table:
| composition (I) | V3 | V4 | V5 |
| Content (%) | 0.5 | 81.85 | 16.17 |
The total content of the loop body V4 in the hydrolysate is calculated to be 52.5 percent.
Comparative example 3
Adding 110ml of water and 450ml of toluene into a 1000ml three-neck flask, dropwise adding 300g of methyl vinyl dichlorosilane under stirring, controlling the dropwise adding time to be 4-6h, observing the reaction temperature (reaching 38 ℃ at the maximum), continuing to react for 2h, removing a water layer, neutralizing an organic phase to the pH of 8 by using 20 wt% of sodium hydroxide, separating an upper oil phase, drying by using anhydrous sodium sulfate, and rectifying under normal pressure to remove the toluene to obtain 177g of hydrolysate. The hydrolysate was subjected to rectification under reduced pressure, and the fraction boiling at 155 ℃ onward (745 mm Hg) was collected to give 87.6g of fraction, which was sampled for gas chromatography.
The contents of the various substances in the fractions are shown in the following table:
| composition (I) | V3 | V4 | V5 |
| Content (%) | 2.21 | 81.05 | 15.61 |
The total content of the loop body V4 in the hydrolysate is calculated to be 40.1 percent.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (15)
1. A preparation method of tetramethyltetravinylcyclotetrasiloxane is characterized by comprising the following steps:
(1) adding methylvinyl dichlorosilane into a low-temperature solvent system, reacting at a low temperature for a period of time after the addition is finished, then heating to a high temperature condition for cyclization reaction, and cooling and separating the reaction liquid after the reaction is finished to obtain an acid water layer and an oil layer;
wherein the solvent system comprises water and a surfactant, and the surfactant is selected from at least one of octyl phenyl polyoxyethylene ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester and sodium dodecyl sulfonate;
(2) adding a salt solution into the oil layer for washing and settling, adjusting the pH value of the mixture, and separating out an aqueous hydrolyzate;
(3) and carrying out reduced pressure rectification on the hydrolysate to obtain fraction containing tetramethyl tetravinylcyclotetrasiloxane.
2. The method according to claim 1, wherein in the step (1), the mass ratio of the water to the methylvinyldichlorosilane is (2-3): 1.
3. The method according to claim 1, wherein in the step (1), the surfactant is octylphenyl polyoxyethylene ether.
4. The production method according to any one of claims 1 to 3, wherein in step (1), the concentration of the surfactant in the low-temperature solvent system is 200-1000 ppm.
5. The production method according to any one of claims 1 to 3, wherein the low temperature in the step (1) means a temperature of 10 to 25 ℃.
6. The method according to claim 5, wherein the low-temperature reaction time in the step (1) is 1 to 5 hours.
7. The production method according to any one of claims 1 to 3, wherein the temperature of the cyclization reaction in step (1) is 50 to 60 ℃.
8. The method of claim 7, wherein; in the step (1), the cyclization reaction is carried out for 3 to 5 hours.
9. The production method according to any one of claims 1 to 3, wherein in the step (2), the salt solution is at least one selected from the group consisting of a sodium chloride solution, a potassium chloride solution, a sodium bromide solution, and a potassium bromide solution.
10. The production method according to any one of claims 1 to 3, wherein in the step (2), the salt solution has a density higher than that of tetramethyltetravinylcyclotetrasiloxane.
11. The production method according to any one of claims 1 to 3, wherein in the step (2), the pH is adjusted by adding a base to the mixture.
12. The production method according to any one of claims 1 to 3, wherein in the step (2), the pH is adjusted to 8 to 9.
13. The process according to any one of claims 1 to 3, wherein in the step (3), the hydrolysate is dried before the vacuum distillation.
14. The method as claimed in any one of claims 1 to 3, wherein in step (3), the vacuum distillation collects 730-745 mm Hg fractions with a boiling point of 117-123 ℃.
15. The production method according to any one of claims 1 to 3, characterized by further comprising step (4): and collecting residual liquid and/or front fraction after vacuum distillation, cracking the residual liquid and/or front fraction to obtain cracking mixed ring bodies, and rectifying the cracking mixed ring bodies to obtain ring bodies V4.
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