A series of lithium complexes were prepared from 2(N-piperazinyl-N'-methyl)-2-methylene-4-R'-6-R-phenols ([ONN](RR')) and characterized through elemental analysis, (1)H and (13)C{(1)H} NMR spectroscopy, and X-ray crystallography. Treatment of the ligands with n-butyllithium afforded {Li[ONN](RR')}(3) [R = Me, R' = (t)Bu, (1); R = R' = (t)Bu (2); R = R' = (t)Am, (3), (t)Am = C(CH(3))(2)CH(2)CH(3...

A novel automated transesterification (ATE) technique has been developed for the quantitative determination of acid components used in synthesizing ester-based oils. The ATE technique has been successfully tested over a period of more than five years using several commercially available ester-based new and used refrigeration oils and jet oils. In this automated technique, the ester-based oil is...

The major challenges for industrial commercialized biodiesel production from microalgae are the high cost of downstream processing such as dewatering and drying, utilization of large volumes of solvent and laborious extraction processes. In order to address these issues the microwave irradiation method was used to produce biodiesel directly from wet microalgae biomass. This alternative method o...

Introduction Glycerol is the main byproduct of biodiesel production. Nowadays, glycerol surplus is becoming a matter of environmental and economic concern. Therefore, new ideas to convert glycerol in more valuable compounds are needed. Monoglyceride (MG) synthesis by glycerol (Gly) transesterification with fatty acid methyl esters (FAME), Figure 1, is an attractive option to transform this biom...

Methyl esters were produced by transesterification of palm oil with methanol in the presence of a catalyst (KOH). The rate of transesterification in a batch reactor increased with temperature up to 60°C. (Higher temperatures did not reduce the time to reach maximal conversion. The conversion of triglycerides (-TG), diglycerides (-DG) and monoglycerides (-MG) appeared to be second order up to 30...

Heterogeneous catalysts are promising for the transesterification reaction of vegetable oils to produce biodiesel and have been studied intensively over the last decade. Unlike the homogeneous catalysts, heterogeneous catalysts can be easily separated from reaction mixture and reused for many times. They are environmentally benign and could be easily operated in continuous processes. This revie...

Specific mechanisms must exist to ensure fidelity in selecting the AG dinucleotide that functions as the 3' splice site during the second transesterification step of splicing. Here we show that the optimal location for this AG is within a narrow distance (19 to 23 nucleotides [nt]) downstream from the branch point sequence (BPS). Contrary to previous expectations, AGs located less than 23 nt fr...

The present study deals with the enzymatic synthesis of biodiesel by transesterification of Jatropha oil (Jatropha curcas L.) with ethanol in a solvent-free system. Seven commercial lipase preparations immobilized by covalent attachment on epoxy-polysiloxane-polyvinyl alcohol composite (epoxy-SiO2-PVA) were tested as biocatalysts. Among them, immobilized lipases from Pseudomonas fluorescens (li...

In this study, biodiesel was produced from sludge palm oil (SPO) using tolune-4-sulfonic monohydrate acid (PTSA) as an acid catalyst in different dosages in the presence of methanol to convert free fatty acid (FFA) to fatty acid methyl ester (FAME), followed by a transesterification process using an alkaline catalyst. In the first step, acid catalyzed esterification reduced the high FFA content...

Transesterification of starch with methyl betainate was studied for the first time, both in aprotic media and solid state, under alkaline acidic conditions. Betaine hydrochloride esterified methanol, attaining a conversion 86%. Starch then converted into either N,N-dimethylformamide or dimethyl sulfoxide, using sulfuric acid as catalyst pre-activating polymer NaOH/ethanol. Furthermore, solid-st...