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 Melamine
108-78-1

Melamine synthesis

14synthesis methods
The standard route to melamine is from urea. Urea is heated in the presence of ammonia at 250-350°C and 4--20 MPa. The reaction probably involves the simultaneous dehydration and hydration of urea to form cyanamide and ammonium carbamate; trimerization of the cyanamide then leads to melamine:


Thus only 50% of the urea used gives melamine in one step and ammonium carbamate has to be separated and converted to urea for recycling. Despite this limitation, the urea route is the most economical of currently available routes.
780722-26-1 Synthesis
Guanidine, cyano-, (E)- (9CI)

780722-26-1
4 suppliers
inquiry

-

Yield:108-78-1 93%

Reaction Conditions:

with potassium hydroxide in water monomer;dimethyl sulfoxide;

Steps:

4 EXAMPLE 4

EXAMPLE 4 A solution of 30 g of dicyandiamide and 30 g of solid cyanamide in 120 g of dimethylsulfoxide is added over a period of 11 minutes to a mixture, heated to 180° C, of 4.0 g of potassium hydroxide and 4.0 g of dicyandiamide in 80 g of dimethylsulfoxide. After an additional 5 minutes of reaction time at 180° C the mixture is cooled. The precipitated melamine is removed by filtration, stirred up in water, and again filtered. The first yield amounts to 53.8 g of melamine or 84.1%. As a second yield, an additional 5.7 g of 8.9% of melamine was found in the filtrate and wash water, so that the total yield amounted to 93.0%.

References:

US4069383,1978,A

Melamine Related Search:

新巴尔虎右旗| 防城港市| 阳江市| 洱源县| 阿图什市| 山东省| 光山县| 凤庆县| 美姑县| 临沧市| 奉新县| 兴化市| 娄烦县| 曲松县| 衡山县| 锡林郭勒盟| 凤台县| 榆林市| 万州区| 灵台县| 泰安市| 怀柔区| 慈溪市| 岑溪市| 长治市| 邹平县| 陇川县| 额敏县| 崇仁县| 蒙自县| 日土县| 边坝县| 陆良县| 漾濞| 博乐市| 谷城县| 当雄县| 甘孜县| 健康| 河曲县| 张家港市|