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 Selenium
7782-49-2

Selenium synthesis

9synthesis methods
Selenium (Se), a nonmetallic element of the sulfur group, is widely distributed in nature. It is obtained along with tellurium as a by-product of metal ore refining, chiefly from copper deposits. About 16 ton is mined a year globally. The global refinery production of selenium, excluding the U.S. production, increased from about 1,400 metric ton in 2000 to about 1510 metric ton in 2008 and 1500 in 2009.
Because selenium is present in fossil fuels, up to 90% of the selenium content in ambient air is emitted during their combustion. Air pollution concentrations averaged from 0.38 ng/m3 in remote areas to 13 ng/m3 in urban areas. The mass medium particle diameter was 0.92 mm. The worldwide emissions of 10,000 tons/year from natural sources exceed the atmospheric emissions from anthropogenic sources (5100 ton). However, 41,000 tons is emitted into the aquatic ecosystems. The largest contributors are electric power generating plants that produce 18,000 ton; manufacturing processes account for 12,000 ton.
Most of the world’s selenium today is provided by recovery from anode muds of electrolytic copper refineries. Selenium is recovered by roasting these muds with soda or sulfuric acid or by melting them with a soda and niter.
-

Yield:100-66-3 41.3 %Chromat. ,38762-70-8 34 %Chromat. ,7782-49-2 22%

Reaction Conditions:

with hydrogen iodide in chloroform;water at 60; for 6 h;

Steps:

Acidolysis of compound (2).

To a solution of 0.29 g (1 mmol) of compound 2 in 5 mL of CHCl3 was added at stirring 3 mL of HI (54% water solution), themixture was heated at 60°C and kept for 6 h. Chloroform solution was separated from water layer and filtered. We isolated 17 mg (22%) of selenium. According to GC-MS data the chloroform solutioncontained anisole (41.3%), initial compound 2(21.4%), and bis(4-methoxyphenyl) diselenide (34%).

References:

Balina;Russkikh;Orlova;Ogneva;Shelkovnikov [Russian Journal of Organic Chemistry,2015,vol. 51,# 2,p. 198 - 201][Zh. Org. Khim.,2015,vol. 51,# 2,p. 210 - 213,4]

Selenium Related Search:

巴中市| 博湖县| 德安县| 安陆市| 永州市| 绥江县| 精河县| 瓮安县| 嘉定区| 简阳市| 武邑县| 南安市| 弥勒县| 齐齐哈尔市| 隆尧县| 永丰县| 洪雅县| 长子县| 吉安市| 夏邑县| 大埔区| 鸡东县| 惠东县| 名山县| 崇信县| 白玉县| 中卫市| 花莲县| 昌平区| 炉霍县| 聂拉木县| 邢台市| 阳曲县| 余庆县| 独山县| 兴宁市| 卫辉市| 贡山| 邻水| 永清县| 钟祥市|