An anti-selective direct catalytic asymmetric aldol reaction of thiolactam is described. A soft Lewis acid/hard Brønsted base cooperative catalyst comprised of mesitylcopper/(R,R)-Ph-BPE exhibited high catalytic performance to produce an anti-aldol product with high stereoselectivity. The highly chemoselective nature of the present catalysis allows for the use of enolizable aldehydes as aldol acceptors
Purification of carboxylic acids by complexation with selective solvents
申请人:Wytcherley Wright Randi
公开号:US20050228195A1
公开(公告)日:2005-10-13
A method and apparatus for purifying carboxylic acids is disclosed. A mixture containing crude carboxylic acid is contacted with a selective crystallization solvent to form a slurry of a salt complex of the carboxylic acid and the selective crystallization solvent. The salt complex is recovered and optionally processed to recover the free carboxylic acid. The method and apparatus of the invention is particularly suitable for purifying aromatic dicarboxylic acids such as terephthalic acid. The present invention also reduces contamination by carboxybenaldehyde isomers in crude phthalic acids by oxidizing the carboxybenzaldehyde to the corresponding phthalic acid.
PROCESS OF PURIFYING AND PRODUCING HIGH PURITY AROMATIC POLYCARBOXYLIC ACIDS
申请人:——
公开号:US20020002304A1
公开(公告)日:2002-01-03
The present invention provides a solvent extraction purification method for aromatic polycarboxylic acids that meet or exceed polymer-grade specification. The method includes dissolving a crude aromatic polycarboxylic acid in a base compound; removing impurities and excessive base compound; and removing residual base compound while making purified product. The purification method removes not only the impurities from the crude acid, but also the residual base compound from finished product that otherwise will contaminate the product. The salt in the cake is converted to product by acid-substitution, thermal decomposition, or electrolysis. The method uses base-extraction solvents to extract base compound and impurities from the salt. The residual base compound in the recovered product is then removed by leaching, stripping, thermal agitating with electromagnetic waves, or evaporation with thermal decomposition. The purification method allows eliminating crystallizers for crystallization and equipment for drying and pneumatically carrying. Finally, the purification method is combined with the oxidation and solvent recovery in prior art to use only one set of process steps, instead of two, to produce aromatic polycarboxylic acids.
Sulfone-sulfoxide compositions for enhanced aromatic extraction
申请人:——
公开号:US20030045766A1
公开(公告)日:2003-03-06
The invention relates to an extractive distillation composition for at least partially separating a mixture of hydrocarbon compounds comprising:
a. at least on one organic sulfoxide of the formula
R
1
—SO—R
2
, and
b. at least on one organic sulfone of the formula
R
3
—SO
2
—R
4
wherein R
1
, R
2
, R
3
, and R
4
have at least one carbon atom and can be the same or different, and to processes for extractive distillation employing the extractive distillation composition.
本发明涉及一种用于至少部分分离烃类化合物混合物的萃取蒸馏组合物,该组合物包括
a. 至少一种式中的有机亚砜
R
1
-SO-R
2
和
b. 至少一种式中的有机砜
R
3
-SO
2
-R
4
其中 R
1
, R
2
, R
3
和 R
4
至少有一个碳原子,可以相同也可以不同,以及使用萃取蒸馏组合物的萃取蒸馏工艺。
TAMARU YOSHINAO; KAGOTANI MASAHIRO; YOSHIDA ZEN-ICHI, J. ORG. CHEM., 1980, 45, NO 25, 5221-5223
作者:TAMARU YOSHINAO、 KAGOTANI MASAHIRO、 YOSHIDA ZEN-ICHI