Savita Kaul

Immobilized oxo-vanadium Schiff base on graphene oxide as an efficient and recyclable catalyst for the epoxidation of fatty acids and esters

Oxo-vanadium Schiff base was covalently immobilized onto chemically functionalized graphene oxide (GO) using 3-aminopropyltriethoxysilane as a coupler. The loading of vanadyl Schiff base onto GO nanosheets was confirmed by FTIR, XRD, TGA, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The synthesized heterogeneous catalyst was found to be efficient and selective for the epoxidation of fatty acids and esters using t-butyl hydroperoxide (TBHP) as an oxidant. Interestingly, the immobilized catalyst showed a higher catalytic efficiency than the homogeneous vanadyl acetylacetonate. The recycling experiment results indicated that the catalyst was highly stable and maintained very high activity, and selectivity even after being used for six cycles.

Simple and Convenient One‐Pot Synthesis of Benzimidazoles and Benzoxazoles using N,N‐Dimethylchlorosulfitemethaniminium Chloride as Condensing Agent

Abstract N,N‐Dimethylchlorosulfitemethaniminium chloride (SOCl2‐DMF) has been found to be an efficient reagent for the one‐pot synthesis of benzimidazoles and benzoxazoles in excellent yield by condensation of carboxylic acids with o‐phenylenediamine/2‐amino‐phenol.

Clean synthesis of biolubricant range esters using novel liquid lipase enzyme in solvent free medium.

In view of the rising global problems of environment pollution and degradation, the present process provides a ‘green solution’ to the synthesis of higher esters of lubricant range, more specifically in the range C12-C36, using different combinations of acids and alcohols, in a single step reaction. The esters produced are biodegradable in nature and have a plethora of uses, such as in additives, as lubricating oils and other hydraulic fluids. The enzymatic esterification was performed using liquid (non-immobilized or free) lipase enzyme, without any additional organic solvent. Soluble lipase proves to be superior to immobilized enzymes as it is more cost effective and provides a faster process for the production of higher esters of lubricant range. An interesting finding was, that the lipase enzyme showed higher conversion rates with increasing carbon number of straight chain alcohols and acids. Reactions were carried out for the optimization of initial water concentration, temperature, pH of the substrate mixture and the chain length of the substrates. Under optimized conditions, the method was suitable to achieve ~ 99% conversion. Thus, the process provides an environment friendly, enzymatic alternative to the chemical route which is currently used in the industrial synthesis of lubricant components.

A SIMPLE AND CONVENIENT ONE-POT SYNTHESIS OF FATTY ACID ESTERS FROM HINDERED ALCOHOLS USING N,N-DIMETHYLCHLORO-SULFITEMETHANIMINIUM CHLORIDE AS DEHYDRATING AGENT

ABSTRACT N,N-Dimethylchlorosulfitemethaniminium chloride (SOCl2-DMF) has been found to be an efficient reagent for one-pot synthesis of esters from equimolar amounts of fatty acids and hindered alcohols under mild conditions.

Carbocatalysis: N-doped reduced graphene oxide catalyzed esterification of fatty acids with long chain alcohols

Nitrogen doped reduced graphene oxide (N-rGO), 5.8% N readily synthesized from the thermal annealing of graphene oxide (GO) in ammonium hydroxide at 453 K, was demonstrated to be a superior metal-free non-acidic carbo-catalyst for the esterification of fatty acids with different alcohols. The effect of various reaction parameters such as reaction temperature, reaction time, catalyst amount etc. has been studied. The developed catalyst was found to be highly stable and exhibited consistent reusability for seven cycles without any significant decrease in the product yields.

Industrial resin “INDION 130” modified with vanadyl cations as highly efficient heterogeneous catalyst for epoxidation of fatty compounds with TBHP as oxidant

Industrial grade cation-exchange resin “INDION 130” was modified with vanadyl cations by an ion-exchange method and then used for the epoxidation of unsaturated fatty materials including acids, esters and vegetable oils using tert-butyl hydroperoxide (TBHP) in decane as oxidant. The effect of oxidant/double bond ratio, catalyst concentration, recycling of the catalyst and temperature on the conversion to epoxides was studied. After the epoxidation, the catalyst could easily be recovered by filtration and successfully reused for at least seven runs without any loss in catalytic activity.

Optimization of Biodiesel Production by Response Surface Methodology and Genetic Algorithm

The biodiesel production from alkali-catalyzed transesterification of karanja oil was investigated. In this study, the effect of three parameters, i.e., reaction temperature, catalyst concentration, and molar ratio of methanol to oil on biodiesel yield was studied. Central composite design (CCD) along with response surface methodology (RSM) was used for designing experiments and estimating the quadratic response surface. Catalyst concentration was found to have a negative effect on biodiesel yield, whereas molar ratio showed positive effect. Temperature and molar ratio showed significant interaction effect. The reaction conditions were optimized for maximum response, i.e., biodiesel yield from RSM. The program for the RSM model, coupled with genetic algorithm (GA), was developed for predicting the optimized process parameters for maximum biodiesel yield to obtain a global optimal solution. The results were found to be similar from both of the methods.

Biocatalytic green approach for epoxidation of fatty compounds derived from soyadeodistillate under acid free conditions

An efficient green approach for the biocatalytic epoxidation of fatty compounds derived from soyadeodistillate using Fermase CalB enzyme with hydrogen peroxide under acid free conditions is described. To the best of our knowledge this is the first report on the chemoenzymatic epoxidation of fatty esters having branched alkyl chain without using additional acid as an oxygen carrier. After completion of the reaction the immobilized enzyme catalyst was easily recovered by filtration and reused for successive four runs with the marginal loss in catalytic activity.

Evaluation of Chlorella Minutissima Oil for Biodiesel Production

Present work is an attempt to focus on screening of microalgae chlorella minutissima, extraction of oil, and conversion of oil into biodiesel. The experimental results are supported by scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDX), high-performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS) analytical techniques. The SEM/EDX results indicate microalgae contain several elements that are required for lipid metabolism, e.g., calcium, magnesium, iron, potassium, and nitrogen. HPLC analysis of hexane extracted oil shows the presence of 74.27 % of free fatty acids, 10.65 % of fatty acid esters, and 13.74 % triglycerides, besides unidentified component 1.34 %. These results are in close agreement with the high acid value of the oil. The presence of fatty acid esters in the oil were also confirmed by GC-MS analysis. Under optimized conditions, of acid catalyzed transesterification >97 % conversion of microalgae oil into FAME is observed. The studies indicate that lower reaction time is favorable for conversion to FAMEs. However, for the purpose of biodiesel feedstock, any increase in the lipid content of the algae will improve the efficiency of the process.

Guanidine based task specific ionic liquids for the synthesis of biolubricant range esters under solvent-free condition

Guanidine-based task specific ionic liquids (ILs) were synthesized from the reaction of 1,1,3,3-tetramethyl guanidine with protic acids and used for the synthesis of higher alcohol esters of fatty acids as biolubes under solvent free condition. The synthesized 1,1,3,3-tetramethylguanidinium hydrogen sulphate (TMG·HSO4) was found to be most effective among the different ILs including 1,1,3,3-tetramethylguanidinium acetate (TMG·Ac), 1,1,3,3-tetramethylguanidinium hydrogen phosphate (TMG·H2PO4) and 1,1,3,3-tetramethylguanidinium trifluoro acetate (TMG·TFA). The effect of various reaction parameters such as reaction temperature, reaction time, catalyst amount etc. has been studied. After completion the reaction the esterification product was isolated and the recovered IL was reused for several runs without loss in catalytic activity.