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 Barbituric acid
67-52-7

Barbituric acid synthesis

13synthesis methods
Barbituric acid is derived By the reaction of diethyl malonate and urea. First put Urea in a reaction tank containing methanol ,heat , reflux , dissolve, then add the dried diethyl malonate and sodium methoxide, the reaction is refluxed at 66-68°C for 4-5h, after distillation to recover methanol, cooling to 40-50°C, add dilute hydrochloric acid to adjust to pH 1-2.Cool to room temperature, throw to obtain crude, wash with distilled water once, dry to get crude , and then purify with water and activated carbon, dry to obtain products. Industrial barbituric acid is white or pink crystalline powder, strongly acidic, more than 98% content, melting point ≥245°C. Material consumption fixed: diethyl malonate 1098kg/t, urea 476kg/t, hydrochloric acid (reagent grade III) 681kg/t, sodium methanol (28%) 369kg/t, methanol 1025kg/t.
-

Yield:67-52-7 70%

Reaction Conditions:

sodium methylate in ethylene glycol at 110; for 6 h;Conversion of starting material;

Steps:

15

Barbituric acid Starting Materials Diethyl malonate 0.5 mol Barbituric acid Starting Materials Diethyl malonate 0.5 mol Urea 0.55 mol Sodium methoxide (catalyst) 0.5 mol Ethylene Glycol 223 g. Operating Conditions Pressure Atmospheric Temperature/time regime 110° C./6 h. Reaction Progress Monitored by TLC using Merck's silica gel plates, benzene- methanol (1:1) Work-up The reaction mixture was cooled to 60° C., diluted with 500 mL water at 50° C., made acidic (to a blue color with congo red indicator) by addition of 55.8 g. concentrated aqueous hydrochloric acid, refri- gerated overnight and filtered. The filter cake was washed with 50 mL cold (10° C.) water and dried at 90° C. during 4 h. 44.6 g, of white crystals, m.p. 245° C. (dec.) were obtained (literature 248° C. “with some decomposition”) Yield 70%

References:

US2005/27120,2005,A1 Location in patent:Page/Page column 8

Barbituric acid Related Search:

海兴县| 岢岚县| 富顺县| 昂仁县| 扶余县| 江孜县| 军事| 临沧市| 颍上县| 河西区| 红河县| 枞阳县| 吴旗县| 阿鲁科尔沁旗| 大宁县| 洪雅县| 五家渠市| 云南省| 巴林右旗| 隆回县| 马公市| 大名县| 景德镇市| 拜城县| 于都县| 河东区| 彰武县| 清水河县| 奉新县| 库尔勒市| 时尚| 丹江口市| 高州市| 青浦区| 西和县| 拜泉县| 酉阳| 鹤峰县| 锦州市| 孟村| 巴中市|