DE1620933A1 - Process for the preparation of methylphenylsilicone oils end-blocked with trimethylsilyl groups - Google Patents

Description

Description Process for the production of methylphenyl silicone oils end-blocked with trimethylsilyl groups According to an earlier proposal, it is known that methylphenyl silicone oils of structure I can be produced by hydrolysis and - equilibration of a mixture of diphenyl and dimethyldichlorosilane with bis (trimethylsilyl) sulphate in sulfuric acid solution, which are polymer isomeric with oils of structure II.

I ii. II polymer isomer if in I m: n = 1 s 1 and x in II = 2.

The procedure according to the earlier proposal is responsible for the shortcomings of one unfavorable space and time yield.

There is also the disadvantage of saponification of the dimethyldichlorosilane conditional additional development of hydrogen chloride, which extends the reaction time.

These disadvantages are eliminated with the new process.

It has now been found that by adding a mixture of hexamethyldisiloxane (MM), octamethylcyclotetrasiloxane (D4) - instead of D4, mixtures of Dimethylcyclosiloxanes (D3, D4t D5) or one of cyclic and linear dimethylsiloxanes existing stem oil can be used as it is in the hydrolysis of Dimethyldichlorosilane incurred and diphenyldichlorosilane in the warm to 70 - 80% sulfuric acid the Can introduce diphenylsiloxane, which leads to oils of structure I. By eliminating the saponification of the dimethyldichlorosilane, the amounts of Sulfuric acid and water added to sulfuric acid after equilibration is reduced by half compared to the previous process and by the Working at elevated temperature the response time to a third of the original shortened, i.e. space and time yield are increased. The procedure allows the production of methylphenyl silicone oils from products of direct synthesis of chlorosilanes while circumventing organometallic syntheses, such as the representation of methylphenyldichlorosilane after the expensive and through the use of ether not harmless original process, after which one arrives at oils of structure II. The following Both examples serve to explain the new process: Example 1t In one 6 liter sulphonation flask, which is in a water bath and equipped with a stirrer, contact thermometer, Feed funnel and reflux cooler (- between reflux cooler and The discharge tube for escaping hydrogen chloride is still a container filled with silicone oil Bubble counter switched), 4564 g (= 2745 11 75% sulfuric acid) are presented and heated to 750G.

While maintaining this temperature, within 2 - hours a mixture of 447 g (@ 468 ml at 2o ° o) octamethylcyclotetrasiloxane (D4); 147 g (3 193 ml at 2000) hexamethyldisiloxane (W) and 725 g (# 594 ml at 20 ° C) Diphenyldichlorosilane (Ph2SiCl2) allowed to run. The composition of the approach corresponds stoichimetrically to the formula M2D3 * 1/3 D62 / 3, where M = CH3) 3SiO @ D * = (C6H5) 2SiO ; D = (CH3) 2SiO: D * = 1: 2 and the molar ratio of total units to M units is 10 : 2 = 5 are.

If about 2/3 of the total volume of the aforementioned mixture has run into it, the evolution of gaseous hydrogen chloride begins. Now stir approx.

Continue for 2 - 3 hours at 75 ° C and then add 2100 ml of water afterwards it was checked whether diphenylsilanediol was found in a sample of the siloxane layer when water was added deposited as a solid white mass or not. If the first is the case, then diss means that not all diphenyldichlorosilane has been saponified and as (C6H5) 2SiO has been installed and you still have to stir. The paving speed is very much dependent on the intensity of the stirring device. After adding water The mixture is stirred for a further half an hour and, after the stirring has been switched off, the system is left on is divided into an upper organosilicon and a lower water containing H2SO4 / HCl Separate layer and let cool. The separated organosilicon layer is with 3% by weight of active silica [bleaching earth ~ 7 (based on the amount by weight of siloxane liquid) post-equilibrated at 80 ° C in 6 hours, filtered and extracted from the equilibrated oil the oligomers are distilled off in vacuo at 2-2 torr to 20,000. The distillation residue is filtered through powdered activated charcoal.

It represents an oil of structure I, The physical and chemical Key figures are listed in Table 1.

Example 2: In the same apparatus as described in Example 1 (bubble counter and derivation for HCl fall web), a mixture of 1392 g of methylphenyl silicone stock oil, obtained by hydrolysis of methylphenyl and dimethyldichlorosilane in a molar ratio of 2: 1%, is mixed with 124 g of hexamethyldisiloxane (MM) with 3% by weight of active, powdered, silica (fuller's earth) in 6 hours, equilibrated at 80 ° C. and worked up in the usual way. An oil of structure II is obtained, which is approximately polymer isomeric with the oil of structure I according to Example 1 and the characteristics of which are also shown in Table 1. The initial stoichimetric composition before equilibration is: M2 D'6 @ D31 / 3, where M = (CH3) @ SiO @; ; = (CH3) (C6H5) Sio; D ': D = 2 S 1 and the molar ratio of total D units to M units is 10 s 2 = 5. Key figures Ex. 1: (Structure I) Ex. 2: (Structure II) M2D3 * 1/3 D62 / 3 M2D'62 / 3D31 / 3 Yield of equilibr. Siloxane liquid according to 90% 92% Approach size of the example % Oligomers 10.4% 24.0% % C 50.4 (54.09) 5.1 (54.09) ber. values % H in brackets 6.72 (6.99) 6.52 (6.99) % Si 26.6 (25.56) 24.4 (25.56) d420 1.067 1.091 V20 (cSt) 317 203 V50 (cSt) 102 56.2 V70 (cSt) 58 30 VTC 0.80 0.83 TKV 3.51 4.19 log v20 / v70 0.7373 0.830 nD20 1.4923 1.5110 Stick point (° C) -53 -42 Flash point (° C) +276 +258 Table 1

Claims (1)

Claim process for the production of trimethylsilyl groups end-blocked methylphenyl silicone oils with favorable space and time yield and Elimination of dimethylchlorosilane hydrolysis, characterized in that the diphenylsiloxane units via the diphenyldichlorosilane in the formation of di- and monofunctional units existing methylsiloxane systems through a combination of hydrolysis and equilibration to a procedural stage,