一二三四区视频,亚洲少妇熟女色,日本久热无码视频网,欧美国产日韩大尺度,亚洲a视频,久久少妇一区二区,日韩999无码视频,刺激久久久久久久,啊啊啊啊不要啊在线

Welcome to chemicalbook!
Chinese English Japanese Germany Korea
010-86108875
Try our best to find the right business for you.
Do not miss inquiry messages Please log in to view all inquiry messages.

Welcome back!

ChemicalBook CAS DataBase List 2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane
2554-06-5

2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane synthesis

9synthesis methods
-

Yield:-

Reaction Conditions:

with 18-crown-6 ether;water at 20; for 0.5 h;Overall yield = 90.1 %;

Steps:

11

General procedure: Hydrolysis of alkylchlorosilanes in a solution with a thermometer, a constant pressure dropping funnel and a reflux condenser, Gas) in a 500 ml three-necked flask. 95 g of methyldichlorosilane was uniformly dropped into a three-necked flask containing 95 g of water and 95 g of 6-crown-2 under magnetic stirring. The reaction temperature was controlled at below 20 °C, and the reaction was continued at the same temperature for 0.5 hour after the dropwise addition, and then the reaction solution was transferred to a separatory funnel to allow the solution to stand. The supernatant was subjected to vacuum distillation, get trimethylcyclotrisiloxane (D3H), tetramethylcyclotetrasiloxane (D4H), pentamethylcyclopentasiloxane (D5H), hexamethylcyclohexasiloxane (D6H). The contents of each component were analyzed by gas chromatograph. The results are shown in Table 1. The residual residue and the linear polysiloxane are regenerated under reduced pressure by acid or base, and then returned to the hydrolyzed oil to be re-rectified. The stratified layer of liquid is mainly crown ether and excess water. Can be used for hydrolysis of methyldichlorosilane continue to use. Such as lack of water, can add water. Such as strong acidity, alkali can be used after the use. The separated lower layer of liquid can also be cooled to a certain temperature, the crown ether precipitation, to achieve the purpose of recovery. Add 50 g of 6-crown-2 and 50 g of distilled water to a thermometer, constant pressure dropping funnel and reflux condenser, The HCl gas was passed into a 250 ml three-necked flask, and 50 g of methylvinyldichlorosilane was uniformly dropped into a three-necked flask from a constant pressure dropping funnel under magnetic stirring. The temperature was controlled below 20 °C, and the same procedure as in Example 1. trimethyltrivinylcyclotrisiloxane (D3Vi), tetramethyltetravinylcyclotetrasiloxane (D4Vi), pentamethylpentavinylcyclopentasiloxane (D5Vi), hexamethylhexavinylcyclotetrasiloxane (D6Vi). The contents of each component were analyzed by gas chromatograph. The results are shown in Table 2. The layered lower layer of liquid is mainly solvent and excess water, for methylvinyldichlorosilane hydrolysis continue to use. The solvent in Example 7 was changed to 18-crown-6 and 35 g of 18-crown-6 was dissolved in 50 g of distilled water. 50 g of methylvinyl dichlorosilane was uniformly added dropwise to the three-necked flask under magnetic stirring, the other was the same as Example 7 and Example 1, and the results are shown in Table 2.

References:

CN104292253,2016,B Location in patent:Paragraph 0019; 0033; 0040; 0041; 0045

2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane Related Search:

东源县| 兴化市| 乡城县| 宿松县| 肇庆市| 南川市| 黑河市| 繁峙县| 合肥市| 巴林左旗| 盐池县| 和硕县| 达州市| 凤山市| 宾阳县| 界首市| 屯留县| 建湖县| 普兰县| 闽清县| 东安县| 扎鲁特旗| 衡阳市| 喀喇| 额敏县| 志丹县| 万山特区| 田林县| 临洮县| 囊谦县| 伊金霍洛旗| 获嘉县| 湘阴县| 饶平县| 临湘市| 句容市| 平远县| 铜梁县| 长白| 叙永县| 扎赉特旗|