- Rapid transesterification of aliphatic and aromatic esters using sodium bis(ethylenedioxy)borate-a mild catalyst
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A simple, selective transesterification of aliphatic and aromatic esters using a mild base sodium bis(ethylenedioxy)borate is described. The transesterification reactions were performed both in microwave and ultrasonication. Aromatic compounds forms diesters of ethylene glycol while aliphatic compounds forms only monoesters. The IR, MS and NMR characterization are given. In this work, an environmentally benign process for the production of biodiesel from oils using heterogeneous catalyst was developed. Mild borate catalyst was adopted for the production of biodiesel. A study for optimizing the reaction conditions such as the reaction time, the reaction condition, the use of co-solvent and the amount of catalyst, was performed.
- Ramasubramanian,Gopi, Sreeraj,Matharasi, D. Priya,Narasimhan
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experimental part
p. 3660 - 3662
(2012/01/30)
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- Combinatorial synthesis of PEG oligomer libraries
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A simple chain-extending approach was established for the scale-up of the monoprotected monodisperse PEG diol materials. Reactions of THP-(OCH2CH2)n—OMs (n=4, 8, 12) with a large excess of commercially available H—(OCH2CH2)n—OH (n=1-4) under basic conditions led to THP-(OCH2CH2)n—OH (n=5-15). Similarly, Me-(OCH2CH2)n—OH (n=4-11, 13) were prepared from Me-(OCH2CH2)n—OMs (n=3, 7, 11). For the chain elongation steps, 40-80% yields were achieved through extraction purification. PEG oligomer libraries I and II were generated in 50-95% overall yields by alkylation or acylation of THP-(OCH2CH2)n—OH (n=1-15) followed by deprotection. Alkylation of Me-(OCH2CH2)n—OH (n=1-11, 13) with X—(CH2)m—CO2R (X=Br or OMs) and subsequent hydrolysis led to PEG oligomer library III in 30-60% overall yields. Combinatorial purification techniques were adapted to the larger-scale library synthesis. A total of 498 compounds, each with a weight of 2-5 g and a minimum purity of 90%, were synthesized.
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Page/Page column 11
(2010/02/15)
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