Synthesis of l -threitol-based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

Chirality ◽  
2017 ◽  
Vol 29 (6) ◽  
pp. 257-272 ◽  
Author(s):  
Zsolt Rapi ◽  
Tamás Nemcsok ◽  
Ádám Pálvölgyi ◽  
György Keglevich ◽  
Alajos Grün ◽  
...  
Keyword(s):  
Crown Ethers ◽  
Phase Transfer ◽  
Phase Transfer Catalyst ◽  
Michael Additions

scholarly journals Preparation and application of 4′-carboxybenzo-15-crown-5, a drift-type crown ether phase transfer catalyst

1994 ◽  
Vol 72 (7) ◽  
pp. 1614-1620 ◽  
Author(s):  
Ming-Seng Chou ◽  
Jeng-Shong Shih
Keyword(s):  
Crown Ether ◽  
Crown Ethers ◽  
Phase Transfer ◽  
Ion Pair ◽  
Phase Transfer Catalyst ◽  
Homogeneous Catalyst ◽  
Effective Catalyst ◽  
Reaction Solution ◽  
Styrene Divinylbenzene ◽  
Ether Phase

A new "drift-type" crown ether phase transfer catalyst, 4′-carboxybenzo-15-crown-5 adsorbed on poly(styrene/divinylbenzene)-NR2 resin, was synthesized and applied to catalyze the oxidation of benzhydrol with NaMNO4 as an oxidant. Before the reaction, the drift-type crown ether catalyst was adsorbed on the resin with ion-pair (resin-NR2H+−O2C-monobenzo-15-crown-5) formation. During the reaction period the crown ether catalyst was released from the resin into the reaction solution as a homogeneous catalyst by adjusting the acidity of the solution to 10−1 M HCl to destroy the ion pair between the catalyst and the resin. After the reaction, the crown ether catalyst could be readsorbed on the resin by adjusting the concentration of HCl to 10−5 M and could be readily recovered by filtration. The catalyst, 4′-carboxybenzo- 15-crown-5, was found to be a more effective catalyst than other crown ethers, such as 15-crown-5, 18-crown-6, monobenzo-15-crown-5, and dibenzo-18-crown-5.

β-cyclodextrin grafted on lignin as inverse phase transfer catalyst for the oxidation of benzyl alcohol in H2O

Tetrahedron ◽  
2016 ◽  
Vol 72 (14) ◽  
pp. 1773-1781 ◽  
Author(s):  
Zujin Yang ◽  
Xia Zhang ◽  
Xingdong Yao ◽  
Yanxiong Fang ◽  
Hongyan Chen ◽  
...  
Keyword(s):  
Benzyl Alcohol ◽  
Phase Transfer ◽  
Phase Transfer Catalyst ◽  
Oxidation Of Benzyl Alcohol ◽  
Inverse Phase Transfer Catalyst

Microwave Energy Pretreated In Situ Transesterification of Jatropha Curcas L in the Presence of Phase Transfer Catalyst

2014 ◽  
Vol 625 ◽  
pp. 267-270 ◽  
Author(s):  
Sintayehu Mekuria Hailegiorgis ◽  
Mahadzir Shuhaimi ◽  
Duvvuri Subbarao
Keyword(s):  
Statistical Model ◽  
Jatropha Curcas ◽  
Phase Transfer ◽  
Phase Transfer Catalyst ◽  
In Situ Transesterification ◽  
Heat Pretreatment ◽  
Seed Particles ◽  
Optimum Reaction ◽  
Microwave Heat

In the present work, microwave heat pretreatment of jatropha curcas seed particles and use of phase transfer catalyst (PTC) to enhance in-situ transesterification were utilized together. It was observed that use of alkaline BTMAOH as a PTC and microwave heat pretreatment of jatropha curcas seed particles had substantially increased the reaction rate of in-situ transesterification as compared to the reaction conducted with microwave untreated seeds in the absence of BTMAOH as a PTC. Statistical model equation was developed to investigate the interaction effect of reaction variables and establish optimum reaction condition. At optimum condition, experimentally obtained FAME yield (93.7±1.53% w/w) was in close agreement with statistical model predicted FAME yield (96.75%) at 38°C and 37 minutes of reaction time.

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