DE1023463B - Process for the preparation of cyclic trimeric and tetrameric AEthylvinylsiloxane - Google Patents

Description

GERMAN

It is known that many organosilicon compounds with different ones bonded to the silicon atom saturated organic groups and hydrolyzed to the corresponding organosilanols can be. Polymeric siloxanes can be produced from these by condensation. Vinyl substituted Siloxanes are of particular interest because the reactivity of a silicon-bonded vinyl group, the use of special hardening processes that differ from the usual siloxane condensation processes, on polymers enables. These methods are suitable e.g. B. for the production of silicone rubbers from polymers that contain unsaturated groups of this type. Vinyl groups bonded to silicon can be converted into high molecular weight siloxanes by common chlorosilane mixed hydrolysis processes to be built in.

However, these methods are not entirely satisfactory for many applications. So would the introduction and uniform distribution of very small amounts of silicon-bonded vinyl groups within a polymer difficult to control with mixed hydrolysis. In addition, instead of a mixed hydrolysis, a special process or a reaction either select single low molecular weight siloxanes as starting material economic reasons or because of the desired mechanism of a particular reaction. The compounds obtained according to the present invention are ideally suited for this purpose. she can be used as intermediate products in the manufacture of vinyl group-containing silicones and types of silicone rubbers as well as for the production of copolymers with organic olefins. Further find the compounds are used as modifiers containing vinyl groups in the manufacture of silicone elastomers.

The group of cyclic siloxane polymers produced by the process of the invention includes following connections:

(1) Cyclic, trimeric ethylvinylsiloxane, represented by the formula:

C ₂ H ₅ C ₂ H ₅

I i

C ₂ H ₅

-Si-

O Si - O Si - O

Method of manufacture

of cyclic trimer

and tetrameric ethylvinylsiloxane

Applicant:

Union Carbide Corporation,
New York, NY (V. St. A.)

Representative: Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse

and Dipl.-Chem. Dr. rer. nat. E. Frhr. v. Bad luck man,

Patent Attorneys, Munich 9, Schweigerstr. 2

Claimed priority:
V. St. v. America October 31, 1955

Arthur Noah Pines, Snyder, NY (V. St. A.),
has been named as the inventor

While these compounds are per se cyclic polysiloxanes, if they are independent as chemical compounds are considered, they still act as monomers when used in the representation of linear polymers can be used, each forming a monomeric part of the polymeric chains, the oils, gum resins and other suitable intermediates for carrying out further polymerization reactions. They bring about an effective crosslinking between the linear polymers and copolymers by means of unsaturated hydrocarbon groups contained therein.

■ According to the invention, these substances are obtained by using ethylvinyldichlorosilane, ethylvinyl-

chlorosilane, ethylvinylethoxychlorosilane or ethylvinyldiethoxysilane hydrolyzed at 0 °, the hydrolyzate neutralized and fractionated.

CH = CH ₉ CH = CH ₉ CH = CH ₉

(2) Cyclic, tetrameric ethylvinylsiloxane, represented by the formula:

C ₂ H ₅

C ₂ H ₅

.Si-O Si

O-

C ₂ H ₅

-Si - O-

C ₂ H ₅

-Si - O

CH = CH ₂ CH = CH ₂ CH = CH ₂ CH = CH ₂

example
Production of cyclic ethylvinyltrisiloxane

and ethyl vinyl tetrasiloxane cyclic
A mixture of 257 g of ethylvinyldichlorosilane and 250 ml of diethyl ether was quickly poured into a mixture of 1000 g of ice and 300 ml of diethyl ether with constant stirring to effect hydrolysis of the silanes. The hydrolysis products were transferred to a separating funnel, the used acid layer was separated off and the oily layer was washed twice with 500 ml of water each time. The washed oil was

709 87T / 286

neutralized with ammonia (1 ml of concentrated NH ₄ OH to 500 ml of H ₂ O), dried, filtered and fractionated at 0.3 mm Hg over a 10-tray column.

Fractionation gave 70 g of pure cyclic trimer, [(C ₂ H ₅ ) (CH ₂ = CH) SiO] ₃ , and 46 g of pure cyclic tetramer, [(C ₂ H ₅ ) (CH ₂ = CH) SiO] ₄ , with the following physical properties:

Boiling point ( ⁰ C)
Melting point

( ⁰ C)

Density (g / ml) ...

Bromine absorption
(g bromine /
g substance)
found ...
theoretically

Trimer

55 / 0.3 mm Hg

-6.5
0.957

1.5
1.6

Tetramer

It has been found that the cyclic ethylvinylsiloxanes according to the invention generally with the most organic substances are better tolerated than the cyclic methylvinylsiloxanes. The cyclic ethylvinylsiloxanes have a further advantage over the cyclic methylvinylsiloxanes, which is due to their lower Volatility so that there is less risk of loss of the critical small portion occurs when they are used for copolymerization with other ίο siloxanes at elevated temperatures.

77 / 0.3 mm Hg

below -60 0.972

Claims (1)

PATENT CLAIM: Process for the production of cyclic! trimeric and tetrameric ethylvinylsiloxane, characterized in that that one Äthylvinyldichlorosilan, Äthylvinylchlorosilan, Äthylvinyläthoxychlorosilan or Ethylvinyldiethoxysilane hydrolyzed at 0 °, the hydrolyzate neutralized and fractionated.