CA2046390A1 - Process for the preparation of di-tert.-butoxydiacetoxysilane - Google Patents
Process for the preparation of di-tert.-butoxydiacetoxysilaneInfo
- Publication number
- CA2046390A1 CA2046390A1 CA002046390A CA2046390A CA2046390A1 CA 2046390 A1 CA2046390 A1 CA 2046390A1 CA 002046390 A CA002046390 A CA 002046390A CA 2046390 A CA2046390 A CA 2046390A CA 2046390 A1 CA2046390 A1 CA 2046390A1
- Authority
- CA
- Canada
- Prior art keywords
- tert
- reaction
- butanol
- butoxydiacetoxysilane
- silane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000002360 preparation method Methods 0.000 title claims abstract description 7
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 claims abstract description 19
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 51
- YZVRVDPMGYFCGL-UHFFFAOYSA-N triacetyloxysilyl acetate Chemical compound CC(=O)O[Si](OC(C)=O)(OC(C)=O)OC(C)=O YZVRVDPMGYFCGL-UHFFFAOYSA-N 0.000 claims description 19
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 claims description 2
- 229910003910 SiCl4 Inorganic materials 0.000 claims 1
- 238000002955 isolation Methods 0.000 claims 1
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 abstract description 29
- 239000000203 mixture Substances 0.000 abstract description 6
- 229910000077 silane Inorganic materials 0.000 abstract description 5
- 239000003431 cross linking reagent Substances 0.000 abstract description 2
- 229920001971 elastomer Polymers 0.000 abstract description 2
- 239000000806 elastomer Substances 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 abstract 1
- 238000004821 distillation Methods 0.000 description 16
- 239000000047 product Substances 0.000 description 12
- 238000010626 work up procedure Methods 0.000 description 7
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 description 6
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 6
- 239000010409 thin film Substances 0.000 description 6
- 239000007858 starting material Substances 0.000 description 5
- 238000009835 boiling Methods 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 4
- 239000011541 reaction mixture Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 239000012043 crude product Substances 0.000 description 3
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000000370 acceptor Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 150000003377 silicon compounds Chemical class 0.000 description 2
- 239000005049 silicon tetrachloride Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- KPZGRMZPZLOPBS-UHFFFAOYSA-N 1,3-dichloro-2,2-bis(chloromethyl)propane Chemical compound ClCC(CCl)(CCl)CCl KPZGRMZPZLOPBS-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- WETWJCDKMRHUPV-UHFFFAOYSA-N acetyl chloride Chemical compound CC(Cl)=O WETWJCDKMRHUPV-UHFFFAOYSA-N 0.000 description 1
- 239000012346 acetyl chloride Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- -1 amine hydrochlorides Chemical class 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000004587 chromatography analysis Methods 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 150000003509 tertiary alcohols Chemical class 0.000 description 1
- 238000005292 vacuum distillation Methods 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
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/18—Compounds having one or more C—Si linkages as well as one or more C—O—Si linkages
- C07F7/1896—Compounds having one or more Si-O-acyl linkages
-
- 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
- C07F7/04—Esters of silicic acids
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
Abstract
Abstract of the Disclosure A new process for preparing di-tert.-butoxydiacetoxy-silane from tetraacetoxysilanc and tert.-butanol is disclosed.
The reaction is carried out at temperatures of up to 80°C, and the resultant di-tert.-butoxydiacetoxysilane is subsequently isolated.
The process according to the invention produces a high purity product in almost quantitative yield. Di-ter-t.-butoxydiacetoxy-silane is useful as a crosslinking agent in the preparation of compositions which have a long shelf life in the absence of water and are curable at room temperature on contact with moisture to form elastomers.
The reaction is carried out at temperatures of up to 80°C, and the resultant di-tert.-butoxydiacetoxysilane is subsequently isolated.
The process according to the invention produces a high purity product in almost quantitative yield. Di-ter-t.-butoxydiacetoxy-silane is useful as a crosslinking agent in the preparation of compositions which have a long shelf life in the absence of water and are curable at room temperature on contact with moisture to form elastomers.
Description
o. æ . 4497 HULS AKTIENGESELLSCHAFT
- PA.TENT DEPARTMENT -P cess for the preparation of di-tert.-butoxydiacetoxy-silane The present invention relates to a process for the preparation of di-tert.-butoxydiacetoxysilane from tetraacetoxysilane and tert.-butanol.
This silicon compound is suitable, in particular, as a crosslinking agent in the preparation of compositions which have a long shelf life in the absence of water and are curable at room temperature on contact with moisture to form elastomers. Such compositions are obtained by mixing dioryanopolysiloxanes containing condensation-capable end groups with crosslinking silicon compounds.
It is known that di-tert.-butoxydiacetoxysilane can be prepared by reacting di-tert.-butoxydichlorosilane with acetic acid in the presence of suitable acid acceptors and solvents (US Patent 2,566,957). It is disadvantageous in this process that, depending on the acid acceptor employed, amine hydrochlorides are produced in a form which is very finely divided, difficult to filter and difficult to wash out. The yields whlch can be achieved with the proc:edure u~ed are about 76~ and require the u~e of the starting material dl-tert.-butoxydichlorosilane, which is only accessible by a complex process.
It is furthermore known that alkoxyacetoxysilane~ can be prepared by reacting alcohols with tetraacetoxysilane (Zhurnal obsce~ Chimii 27 (1957~, p. 921 to 926). In this publication, it is stated that tertiary alcohols react with tetraacetoxysilane only with difficulty. If tert.-butanol is used as the alcohol component, the reaction mixtures must be warmed to temperatures of from 100 to 140C in order to ob1:ain tert.-butoxyacetoxysilanes.
Thus, to prepare di-tert.-butoxydiacetoxysilane, it was 2 ~
- 2 - ~3443-451 necessary to heat a mixture of tetraacetoxysilane and tert.-butanol in the molar ratio 1:2 at up to 100C for 4 hours. Even then, the product yield obtained from the reaction mixture after distillative work-up was only 48%.
The object was therefore to prepare di-tert.-butoxydi-acetoxysilane in a process in which no starting materials which can only be produced by means of considerable technical complexity are used and in which the starting materials employed are con-verted into the taryet product as quantitatively as possible.
Thus the present invention provides a process for the preparat:ion of di-tert.-butoxydiacetoxysilane, which process comprises reacting te-traacetoxysilane and tert.-butanol at a temperature of up to about 80C and isolating the di-tert.-butoxy-diacetoxysilane so produced.
A preferred embodiment of the process comprises carrying out the reaction of the components tetraacetoxysilane and tert.-butanol in the prescnce of the reaction mixture as produced during the preparation of tetraacetoxysilane from sil:icon tetrachloride and acetic acid.
The sequence in which the -rcac-tants act on one another is imrna-terial for the course of the reaction. The preferred form of the react:ion course comprises allowiny the tert.-butanol in liqu:id Eorm to act on thc initially introduced solid tetraacetoxy-silane. Thc end of the rcaction can be detectcd rom the initially heterogcncous systern becoming homogeneous. This state is 2~63~
- 2a - 23443-451 established about 30 minutes after completion of the combination of the reactants. In contrast to the process described in the abovementioned publi.cation (Zhurnal obscej Chimii), the reaction, which is known per se, proceeds according to the invention in the claimed temperature range within a short time.
Subsequen-t heating after a homogeneous reaction solution 2~3~Q
- PA.TENT DEPARTMENT -P cess for the preparation of di-tert.-butoxydiacetoxy-silane The present invention relates to a process for the preparation of di-tert.-butoxydiacetoxysilane from tetraacetoxysilane and tert.-butanol.
This silicon compound is suitable, in particular, as a crosslinking agent in the preparation of compositions which have a long shelf life in the absence of water and are curable at room temperature on contact with moisture to form elastomers. Such compositions are obtained by mixing dioryanopolysiloxanes containing condensation-capable end groups with crosslinking silicon compounds.
It is known that di-tert.-butoxydiacetoxysilane can be prepared by reacting di-tert.-butoxydichlorosilane with acetic acid in the presence of suitable acid acceptors and solvents (US Patent 2,566,957). It is disadvantageous in this process that, depending on the acid acceptor employed, amine hydrochlorides are produced in a form which is very finely divided, difficult to filter and difficult to wash out. The yields whlch can be achieved with the proc:edure u~ed are about 76~ and require the u~e of the starting material dl-tert.-butoxydichlorosilane, which is only accessible by a complex process.
It is furthermore known that alkoxyacetoxysilane~ can be prepared by reacting alcohols with tetraacetoxysilane (Zhurnal obsce~ Chimii 27 (1957~, p. 921 to 926). In this publication, it is stated that tertiary alcohols react with tetraacetoxysilane only with difficulty. If tert.-butanol is used as the alcohol component, the reaction mixtures must be warmed to temperatures of from 100 to 140C in order to ob1:ain tert.-butoxyacetoxysilanes.
Thus, to prepare di-tert.-butoxydiacetoxysilane, it was 2 ~
- 2 - ~3443-451 necessary to heat a mixture of tetraacetoxysilane and tert.-butanol in the molar ratio 1:2 at up to 100C for 4 hours. Even then, the product yield obtained from the reaction mixture after distillative work-up was only 48%.
The object was therefore to prepare di-tert.-butoxydi-acetoxysilane in a process in which no starting materials which can only be produced by means of considerable technical complexity are used and in which the starting materials employed are con-verted into the taryet product as quantitatively as possible.
Thus the present invention provides a process for the preparat:ion of di-tert.-butoxydiacetoxysilane, which process comprises reacting te-traacetoxysilane and tert.-butanol at a temperature of up to about 80C and isolating the di-tert.-butoxy-diacetoxysilane so produced.
A preferred embodiment of the process comprises carrying out the reaction of the components tetraacetoxysilane and tert.-butanol in the prescnce of the reaction mixture as produced during the preparation of tetraacetoxysilane from sil:icon tetrachloride and acetic acid.
The sequence in which the -rcac-tants act on one another is imrna-terial for the course of the reaction. The preferred form of the react:ion course comprises allowiny the tert.-butanol in liqu:id Eorm to act on thc initially introduced solid tetraacetoxy-silane. Thc end of the rcaction can be detectcd rom the initially heterogcncous systern becoming homogeneous. This state is 2~63~
- 2a - 23443-451 established about 30 minutes after completion of the combination of the reactants. In contrast to the process described in the abovementioned publi.cation (Zhurnal obscej Chimii), the reaction, which is known per se, proceeds according to the invention in the claimed temperature range within a short time.
Subsequen-t heating after a homogeneous reaction solution 2~3~Q
- 3 - O.Z. 4497 has been prcd~ced is not necessary.
The reacti~n cf tetraacetcxy~ila~e ~ith tert.-butanol can also be carried out in the presence of inert media.
Substances of this type, such as aliphatic hydrocarbons, aromatics or chlorLnated hy~rocarbons, have no specific effect on tk~e reaction proce~dings.
The use of aliphatic hy~rccarbo~s as solvent is par-ticularly a~Lsable if the starting material tetra-acetoxysil2~-e is the ~n-wcrk2d-up product of the reaction of SiCl~ an~ acetic acid.
Since the re c~ion is not accompanied by any evolution of heat, it is possible to c~m~ine the reaction components tetraaceto~ysilane and tert.-butanol without problems, even in relztiYely large æmounts.
The reactic~ can be carr-e~ o~tt elther continuously or batchwise; the reaction is ~referably carried out batch-wise. In a cor.~inuous p~cce~ure, the alcohol component and the tet-aacetorysila~e, if desired suspended in an inert mediu~, are fed sim~lt~neously, taking into account the stoick~ometric circum~tances, into a 3uitable reactor, fo~ e~ample a t~iular reactor. After an appro-l priate re~ e~ce tL~e, ~he reaction procluct di-tert.-butoxydiacetory~i1~n~, ~ u~s of unreacted starting materials, poss~bly saal~ 2~mounts of byproducts and the acetic acid als~ forred lea~e the reactor.
The reactiol o~ the reaction components tetraacetoxy-silane and rertA-butanol ~g carrie~ out according to the invention a~ t~mperatures of up to 80C. When these reaction te~peratures are used, improved yields of di-tert.-butosydL2ceto~ysila~e are obt~ined, which are up to 100% above he yields for ~e prep~ration methods known hitherto.
2~3~0 - 4 - O.Z. 4497 In the reaction of the reaction components tetraacetoxy-silane and tert.-butanol at the claimed temperatures of up to ~0C, the resultant yields of di-tert.-butoxydi-aceto~ysilane vary only insignificantly, a sliqht ten-S dency toward a reduction in yield being detectable withincreasing reaction temperature. For this re~son, the reaction is preferably carried out in the temperature range from 40 to 70 C. If reaction temperatures above 80C are used, the abovementioned reductions in the yield of di-tert.-butoxydiacetoxysilane occur. The lower limit of the temperature range is determined by the melting point of the tert.-butanol, which can be lowered to temperatures of about 0C by adding suitable solvents. It is thus important that the tert.-butanol is in the form of a liquid phase during the reaction.
The reaction components tetraacetoxysilane and tert.-butanol are preferahly employed in a molar ratio of from 1:1.9 to 2.2.
It has proven expedient to react the reaction components in the molar ratio 1~2. If this molar ratio is chosen, reaction proclucts are obtained in the claimed temperature range which are essentially free from the byproducts tert.-butoxytriacetoxysilaneandtri-tert.-butoxyacetoxy-I silane.
The reaction i8 carried out at atmospheric pressure. The use of reduced pressure or superatmospheric pres~ure is possible, but has no significant effect on the reaction proceedings. The cxude products obtained using the process according to the invention are worked up in a manner which is known per se. Any solvent used and the acetic acid formed during the reaction are preferably removed by distillation. Irrespective of the composition of the crude product, the work-up i8 carried out in vacuo from the outset. Precautions are taken during the entire work-up process to ensure that the phase containing the reaction product di-tert.-butoxydiacetoxysilane is not 2~4639~
The reacti~n cf tetraacetcxy~ila~e ~ith tert.-butanol can also be carried out in the presence of inert media.
Substances of this type, such as aliphatic hydrocarbons, aromatics or chlorLnated hy~rocarbons, have no specific effect on tk~e reaction proce~dings.
The use of aliphatic hy~rccarbo~s as solvent is par-ticularly a~Lsable if the starting material tetra-acetoxysil2~-e is the ~n-wcrk2d-up product of the reaction of SiCl~ an~ acetic acid.
Since the re c~ion is not accompanied by any evolution of heat, it is possible to c~m~ine the reaction components tetraaceto~ysilane and tert.-butanol without problems, even in relztiYely large æmounts.
The reactic~ can be carr-e~ o~tt elther continuously or batchwise; the reaction is ~referably carried out batch-wise. In a cor.~inuous p~cce~ure, the alcohol component and the tet-aacetorysila~e, if desired suspended in an inert mediu~, are fed sim~lt~neously, taking into account the stoick~ometric circum~tances, into a 3uitable reactor, fo~ e~ample a t~iular reactor. After an appro-l priate re~ e~ce tL~e, ~he reaction procluct di-tert.-butoxydiacetory~i1~n~, ~ u~s of unreacted starting materials, poss~bly saal~ 2~mounts of byproducts and the acetic acid als~ forred lea~e the reactor.
The reactiol o~ the reaction components tetraacetoxy-silane and rertA-butanol ~g carrie~ out according to the invention a~ t~mperatures of up to 80C. When these reaction te~peratures are used, improved yields of di-tert.-butosydL2ceto~ysila~e are obt~ined, which are up to 100% above he yields for ~e prep~ration methods known hitherto.
2~3~0 - 4 - O.Z. 4497 In the reaction of the reaction components tetraacetoxy-silane and tert.-butanol at the claimed temperatures of up to ~0C, the resultant yields of di-tert.-butoxydi-aceto~ysilane vary only insignificantly, a sliqht ten-S dency toward a reduction in yield being detectable withincreasing reaction temperature. For this re~son, the reaction is preferably carried out in the temperature range from 40 to 70 C. If reaction temperatures above 80C are used, the abovementioned reductions in the yield of di-tert.-butoxydiacetoxysilane occur. The lower limit of the temperature range is determined by the melting point of the tert.-butanol, which can be lowered to temperatures of about 0C by adding suitable solvents. It is thus important that the tert.-butanol is in the form of a liquid phase during the reaction.
The reaction components tetraacetoxysilane and tert.-butanol are preferahly employed in a molar ratio of from 1:1.9 to 2.2.
It has proven expedient to react the reaction components in the molar ratio 1~2. If this molar ratio is chosen, reaction proclucts are obtained in the claimed temperature range which are essentially free from the byproducts tert.-butoxytriacetoxysilaneandtri-tert.-butoxyacetoxy-I silane.
The reaction i8 carried out at atmospheric pressure. The use of reduced pressure or superatmospheric pres~ure is possible, but has no significant effect on the reaction proceedings. The cxude products obtained using the process according to the invention are worked up in a manner which is known per se. Any solvent used and the acetic acid formed during the reaction are preferably removed by distillation. Irrespective of the composition of the crude product, the work-up i8 carried out in vacuo from the outset. Precautions are taken during the entire work-up process to ensure that the phase containing the reaction product di-tert.-butoxydiacetoxysilane is not 2~4639~
- 5 - O.Z. 4497 warmed to above 90C for any length of time.
Af~er removal of all the low-boiling substances from the reaction mixture by distillation, di-tert.-butoxydi-acetoxysilane is obtained in a quality which is adequate for many appli~ations. Use in demanding areas of applica-tion requires a particular product quality, which is obtained by final distillation in a thin-film evaporator in vacuo at temperatures of below ~0C.
The invention is illustrated with reference to the examples given below:
Example 1 1056 g (4 mol) of tetraacetoxysilane are introduced into a 4 litre twin-jacket flask equipped with a reflux condenser, stirrer, dropping funnel and thermometer and heated by means of a temperature-controlled heating circuit. 480 g (8 mol) of tert.-butanol are added from the dropping funnel over the course of 3 minutes to the initially introduced tetraacetoxysi]ane, which is kept at a temperature of 23C via the temperature-controlled heating circuit. The reaction is complete within 30 minutes, which can be d0tected from the complete di~ap-pearance of the tetraacetoxy~ilane. ~n~ly~i~ of the flask product by gals chromatography (GC) indicates the prHSenCe of the targe1: product di-tert.-butoxydiacetoxysilane in addition to acetic acid. The crude product is transferred into a distillation apparatus, which comprises a twin-~acket distillation still with connected temperature-controlled heating circuit and inserted thermometer, and a distillation attachment which i8 connected to a vacuum pump via a cold trap. The crude product employed is freed from all the acetic acid within two hours at a bottom temperature of up to a maximum of 85C. A c].ear, vir-tually colourless liquid (1153 g) which has a purity (GC) of 97~ rem~ins. Distillative work-up of the still product in a glass laboratory thin-film evaporator in vacuo gives 2~3~
Af~er removal of all the low-boiling substances from the reaction mixture by distillation, di-tert.-butoxydi-acetoxysilane is obtained in a quality which is adequate for many appli~ations. Use in demanding areas of applica-tion requires a particular product quality, which is obtained by final distillation in a thin-film evaporator in vacuo at temperatures of below ~0C.
The invention is illustrated with reference to the examples given below:
Example 1 1056 g (4 mol) of tetraacetoxysilane are introduced into a 4 litre twin-jacket flask equipped with a reflux condenser, stirrer, dropping funnel and thermometer and heated by means of a temperature-controlled heating circuit. 480 g (8 mol) of tert.-butanol are added from the dropping funnel over the course of 3 minutes to the initially introduced tetraacetoxysi]ane, which is kept at a temperature of 23C via the temperature-controlled heating circuit. The reaction is complete within 30 minutes, which can be d0tected from the complete di~ap-pearance of the tetraacetoxy~ilane. ~n~ly~i~ of the flask product by gals chromatography (GC) indicates the prHSenCe of the targe1: product di-tert.-butoxydiacetoxysilane in addition to acetic acid. The crude product is transferred into a distillation apparatus, which comprises a twin-~acket distillation still with connected temperature-controlled heating circuit and inserted thermometer, and a distillation attachment which i8 connected to a vacuum pump via a cold trap. The crude product employed is freed from all the acetic acid within two hours at a bottom temperature of up to a maximum of 85C. A c].ear, vir-tually colourless liquid (1153 g) which has a purity (GC) of 97~ rem~ins. Distillative work-up of the still product in a glass laboratory thin-film evaporator in vacuo gives 2~3~
- 6 ~ O.Z. 4497 a distillate of 1131 g having a purity (GC~ of 98% and a residue of 22 g.
Example 2 The experiment of Example 1 is repeated, but the reaction temperature used is 80C.
Analysis of the crude reaction product by GC indicates the presence of the target product in addition to acetic acid, extremely small amounts of the compounds tert.-butoxytriacetoxysilane,tri-tert.-butoxyacetoxysilaneand ~iloxanes.
After removal of the acetic acid by distillation, a slightly yellowish still residue (1152 g) having a purity (GC) of 93.2~ remains. Work-up of this still residue in a thin-film evaporator gives a distillate of 1109 g having a purity of 96.8~ and a residue of 40 g.
Example 3 (comparative exam~le) The experiment of Example 1 is repeated, but the reaction temperature used is 115C.
( Analysis of the crude reac~ion product by GC indLcates the presence of the target product in ~ddition to acetic acid. In addition, an increased presence of siloxane6 is determined. After removal of the low-boiling components by distillation, a yellow residue (1096 g) containing 43.7~ of di-tert.-butoxydiacetoxysilane remains in the distillation still. Distillative work-up gives 465 g of distillate and 598 g of residue.
Example 4 The experiment of Example 2 is repeated, but with 2000 ml of octane added to the initially introduced amount of tetraacetoxysilane. After removal of the octane and the 204~39~
Example 2 The experiment of Example 1 is repeated, but the reaction temperature used is 80C.
Analysis of the crude reaction product by GC indicates the presence of the target product in addition to acetic acid, extremely small amounts of the compounds tert.-butoxytriacetoxysilane,tri-tert.-butoxyacetoxysilaneand ~iloxanes.
After removal of the acetic acid by distillation, a slightly yellowish still residue (1152 g) having a purity (GC) of 93.2~ remains. Work-up of this still residue in a thin-film evaporator gives a distillate of 1109 g having a purity of 96.8~ and a residue of 40 g.
Example 3 (comparative exam~le) The experiment of Example 1 is repeated, but the reaction temperature used is 115C.
( Analysis of the crude reac~ion product by GC indLcates the presence of the target product in ~ddition to acetic acid. In addition, an increased presence of siloxane6 is determined. After removal of the low-boiling components by distillation, a yellow residue (1096 g) containing 43.7~ of di-tert.-butoxydiacetoxysilane remains in the distillation still. Distillative work-up gives 465 g of distillate and 598 g of residue.
Example 4 The experiment of Example 2 is repeated, but with 2000 ml of octane added to the initially introduced amount of tetraacetoxysilane. After removal of the octane and the 204~39~
- 7 - O.Z. 4497 acetic acid by distillation, a slightly yellowi~h re~idue (1160 g) having a purity of 93.9~ remains in the distil-lation still. Work~up in a thin-film evaporator gives a distillate of 1119 g having a purity of 97.3%, and 38 g of residue.
Example 5 (comparative example) The experiment of Example 3 is repeated, but with 2000 ml of octane added to the initially introduced amount of tetraacetoxysilane.
After removal of the octane, the acetic acid and low-boiling components by distillation, a yellow product (1096 g) containing 59.7% of di-tert.-butoxydiacetoxy-silane (GC) remains in the distillation still.
Distillative work-up of this still residue gives 658 g of distillate and 434 g of residue.
Example 6 500 kg of silicon tetrachloride and 400 litres of hexane are introduce!d into a 3 m3 reactor fitted with a cooling attachment and connected via the latter to a water-pump vacuum. 740 ]cg of acetic acid are matered ln over the cour~e of 5 hours at a reaction medi.um temperature of 70C. The hydrogen chloride formed continuously i~
removed by ~uction. When it has been removed completely, 436 kg of tert.-butanol are added to the tetraacetoxy-silane/hex~ne system over the course of 20 minutes. 30minutes later, the reactor contents are tran~ferred into a distlllation apparatus, and the low-boiling components (hexane, acetic acid and others) are removed in vacuo.
The pale-yellow still residue (856 kg, purity (GC) 93.6%) is, after filtration, either packaged as a commercial product or immediately worked up in a thin-film eva-porator. In the latter case, 825 kg of distillate having a purity (GC) of 97~ are obtained.
2~6390 - 8 ~ O.Z. 4497 _ample 7 1050 g of acetic anhydride are in~.oduced into a reaction flask fitted with a distillation attachment. 350 g of silicon tetrachloride are metered in over the course of about 5 minutes at 25C. The precipitated tetraacetoxy-silane is freed from acetyl chloride formed and excess acetic anhydride by distillation. 350 q of tert.-butanol are added to the dry tetraacetoxysilane material at room temperature. The di-tert.-butoxydiacetoxysilane/acetic acid mixture produced is freed from acetic acid by vacuum distillation and subsequently purified by distillation in a thin-film evaporator. 578 g of colourless di-tert.-butoxydiacetoxy~ilane having a purity (GC) of 98~ are obtalned in this way.
Example 5 (comparative example) The experiment of Example 3 is repeated, but with 2000 ml of octane added to the initially introduced amount of tetraacetoxysilane.
After removal of the octane, the acetic acid and low-boiling components by distillation, a yellow product (1096 g) containing 59.7% of di-tert.-butoxydiacetoxy-silane (GC) remains in the distillation still.
Distillative work-up of this still residue gives 658 g of distillate and 434 g of residue.
Example 6 500 kg of silicon tetrachloride and 400 litres of hexane are introduce!d into a 3 m3 reactor fitted with a cooling attachment and connected via the latter to a water-pump vacuum. 740 ]cg of acetic acid are matered ln over the cour~e of 5 hours at a reaction medi.um temperature of 70C. The hydrogen chloride formed continuously i~
removed by ~uction. When it has been removed completely, 436 kg of tert.-butanol are added to the tetraacetoxy-silane/hex~ne system over the course of 20 minutes. 30minutes later, the reactor contents are tran~ferred into a distlllation apparatus, and the low-boiling components (hexane, acetic acid and others) are removed in vacuo.
The pale-yellow still residue (856 kg, purity (GC) 93.6%) is, after filtration, either packaged as a commercial product or immediately worked up in a thin-film eva-porator. In the latter case, 825 kg of distillate having a purity (GC) of 97~ are obtained.
2~6390 - 8 ~ O.Z. 4497 _ample 7 1050 g of acetic anhydride are in~.oduced into a reaction flask fitted with a distillation attachment. 350 g of silicon tetrachloride are metered in over the course of about 5 minutes at 25C. The precipitated tetraacetoxy-silane is freed from acetyl chloride formed and excess acetic anhydride by distillation. 350 q of tert.-butanol are added to the dry tetraacetoxysilane material at room temperature. The di-tert.-butoxydiacetoxysilane/acetic acid mixture produced is freed from acetic acid by vacuum distillation and subsequently purified by distillation in a thin-film evaporator. 578 g of colourless di-tert.-butoxydiacetoxy~ilane having a purity (GC) of 98~ are obtalned in this way.
Claims (6)
1. A process for the preparation of di-tert.-butoxydi-acetoxysilane, which process comprises reacting tetraacetoxysilane and tert.-butanol at a temperature of up to about 80°C and iso-lating the di-tert.-butoxydiacetoxysilane so produced.
2. A process according to Claim l, wherein tetraacetoxy-silane is prepared by reacting SiCl4 and acetic acid and then reacted without isolation with tert.-butanol.
3. A process according to Claim l or 2, wherein the process is carried out at a temperature of from about 40 to about 70°C.
4. A process according -to Claim l or 2, wherein the process is carried out in an aliphatic hydrocarbon.
5. A process according to Claim l or 2, wherein the molar ratio of tetraacetoxysilane and tert.-butanol is from about 1:1.9 to about 1:2.2.
6. A process according to Claim 5, wherein the molar ratio is about 1:2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4021870A DE4021870A1 (en) | 1990-07-09 | 1990-07-09 | METHOD FOR PRODUCING DITERTIAERBUTOXYDIACETOXYSILANE |
| DEP4021870.8 | 1990-07-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2046390A1 true CA2046390A1 (en) | 1992-01-10 |
Family
ID=6409979
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002046390A Abandoned CA2046390A1 (en) | 1990-07-09 | 1991-07-05 | Process for the preparation of di-tert.-butoxydiacetoxysilane |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0465723B1 (en) |
| JP (1) | JP2820554B2 (en) |
| CA (1) | CA2046390A1 (en) |
| DE (2) | DE4021870A1 (en) |
| ES (1) | ES2068980T3 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19632483A1 (en) * | 1996-08-12 | 1998-02-19 | Basf Ag | Process for the preparation of acyloxyalkoxysilanes |
| US8153566B2 (en) | 2008-09-30 | 2012-04-10 | Cherron Oronite Company LLC | Lubricating oil compositions |
| US8901050B2 (en) | 2010-03-31 | 2014-12-02 | Chevron Oronite Company Llc | Method for improving copper corrosion performance |
| US8933001B2 (en) | 2010-03-31 | 2015-01-13 | Chevron Oronite Company Llc | Method for improving fluorocarbon elastomer seal compatibility |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2986875A (en) * | 1951-11-07 | 1961-06-06 | Gen Electric | Fuel additives |
| NL7311581A (en) * | 1972-08-29 | 1974-03-04 | ||
| JPS6143660A (en) * | 1984-08-07 | 1986-03-03 | Shin Etsu Chem Co Ltd | Room temperature curing organosiloxane composition |
-
1990
- 1990-07-09 DE DE4021870A patent/DE4021870A1/en not_active Withdrawn
- 1990-12-13 DE DE59008730T patent/DE59008730D1/en not_active Revoked
- 1990-12-13 ES ES90124036T patent/ES2068980T3/en not_active Expired - Lifetime
- 1990-12-13 EP EP90124036A patent/EP0465723B1/en not_active Revoked
-
1991
- 1991-07-05 CA CA002046390A patent/CA2046390A1/en not_active Abandoned
- 1991-07-08 JP JP3166582A patent/JP2820554B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0465723B1 (en) | 1995-03-15 |
| DE59008730D1 (en) | 1995-04-20 |
| JPH04230391A (en) | 1992-08-19 |
| JP2820554B2 (en) | 1998-11-05 |
| EP0465723A1 (en) | 1992-01-15 |
| DE4021870A1 (en) | 1992-01-16 |
| ES2068980T3 (en) | 1995-05-01 |
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