Atanu Biswas

Azide Derivatives of Soybean Oil and Fatty Esters

An environmentally friendly water-based pathway to form the azide derivatives of soybean oil and fatty esters is reported. This entails first the formation of epoxides and then the azidization of the epoxides. The azidization reaction is carried out at high yields in water with only a small amount of an ionic liquid as a catalyst. The distribution of azide and alcohol functionalities on the fatty acid moiety is approximately random. This reaction has been applied to methyl oleate, methyl linoleate, soybean oil, and methyl soyate. The resulting structures have been studied by NMR.

Novel modified soybean oil containing hydrazino-ester: synthesis and characterization

A novel synthetic approach for chemical modification of vegetable oils is presented. The structural modification is carried out using diethyl azodicarboxylate (DEAD) in the absence of catalyst and solvent. In a microwave oven the reaction can be achieved in 5–15 minutes. The reaction can also proceed using conventional heat, albeit for a longer time. The products are characterized by 1H, 13C, and two-dimensional NMR.

Synthesis of an Amine−Oleate Derivative Using an Ionic Liquid Catalyst

A facile (and environmentally friendly) reaction between epoxidized methyl oleate and aniline to produce an oleate-aniline adduct, without the formation of fatty amide, was discovered. This reaction was carried out neat, with a catalytic amount of an ionic liquid. No solvent was used, no byproducts were produced, and the ionic liquid could be recovered and recycled. The reaction products were fully characterized by NMR and GC-MS.

Microwave-Assisted Rapid Modification of Zein by Octenyl Succinic Anhydride

ABSTRACT Corn is one of the most important food and industrial crops in the United States. Zein constitutes about half of the endosperm proteins in corn. Potential applications of zein include use in fibers, adhesives, inks, cosmetics, textiles, and chewing gum. Recently, attempts have been made to utilize zein for food coatings and biodegradable materials. The new applications of zein require it to be resistant to water. Thus, we are interested in new routes for chemical modification of zein (Biswas et al, unpublished). 2-Octenyl succinic anhydride (OSA) is extensively used in modifying food starches. Our objective was to take advantage of OSA hydophobicity, flexibility, and compatibility with nonpolar groups and incorporate OSA onto zein. This OSA-modified zein would possess the best of both OSA and zein. A zein solution in dimethyl formamide (DMF) was reacted with various levels of OSA to give modified zein. In a microwave reactor, the reactions proceeded tremendously fast and they were over in 5 min. ...

Use of Nutshells as Fillers in Polymer Composites

Nutshells are agricultural waste products that can be procured at relatively low cost. In this work we examined the possibility of using these biodegradable materials as fillers in poly(lactic acid) and low density polyethylene. The nutshells were ground into powder, blended with the polymer, and then injection molded with final weight varying from 10 to 40 weight %. The mechanical and thermal properties of the composites were then studied. In general, the addition of fillers caused reductions in mechanical properties to varying extents, but thermal properties were only slightly affected. The use of maleic anhydride and peroxide with the fillers had a negative effect on poly(lactic acid) but a slightly positive effect on the stiffness of polyethylene. The results suggested that polymer-nutshell composites may be usable in applications where cost is a concern and where some reductions in mechanical properties are acceptable.

Microwave-assisted synthesis of cyclodextrin polyurethanes

Cyclodextrin (CD) has often been incorporated into polyurethanes in order to facilitate its use in encapsulation or removal of organic species for various applications. In this work a microwave-assisted method has been developed to produce polyurethanes consisting of α-, β-, and γ-CD and three common diisocyanates. As compared to conventional heating, this new synthetic method saves energy, significantly reduces reaction time, and gets similar or improved yield. The reaction products have been fully characterized with (13)C, (1)H, and two-dimensional NMR spectroscopy. With suitable stoichiometry of starting CD and diisocyanate, the resulting CD polyurethane is organic-soluble and water-insoluble and is shown to remove Nile red dye and phenol from water. Possible applications include the removal of undesirable materials from process streams, toxic compounds from the environment, and encapsulation of color or fragrance molecules.

Electrochemical immunosensors for Salmonella detection in food

Pathogen detection is a critical point for the identification and the prevention of problems related to food safety. Failures at detecting contaminations in food may cause outbreaks with drastic consequences to public health. In spite of the real need for obtaining analytical results in the shortest time possible, conventional methods may take several days to produce a diagnosis. Salmonella spp. is the major cause of foodborne diseases worldwide and its absence is a requirement of the health authorities. Biosensors are bioelectronic devices, comprising bioreceptor molecules and transducer elements, able to detect analytes (chemical and/or biological species) rapidly and quantitatively. Electrochemical immunosensors use antibody molecules as bioreceptors and an electrochemical transducer. These devices have been widely used for pathogen detection at low cost. There are four main techniques for electrochemical immunosensors: amperometric, impedimetric, conductometric, and potentiometric. Almost all types of immunosensors are applicable to Salmonella detection. This article reviews the developments and the applications of electrochemical immunosensors for Salmonella detection, particularly the advantages of each specific technique. Immunosensors serve as exciting alternatives to conventional methods, allowing “real-time” and multiple analyses that are essential characteristics for pathogen detection and much desired in health and safety control in the food industry.

Microwave-assisted synthesis of alkyl cellulose in aqueous medium.

Alkyl celluloses are commercial products that are made typically in an alcohol medium over the course of several hours. In this work an alternative, simplified synthesis of alkyl cellulose is reported, using microwave irradiation and aqueous alkaline medium. No alcohol is needed during the reaction. Reaction time is less than 30 min. Conversion varies from 54 to 87%. The degree of substitution varied from 0.2 to 1.0. The production of methyl cellulose and ethyl cellulose was confirmed by (13)C NMR and FTIR analysis.

Preparation of acetonides from soybean oil, methyl soyate, and fatty esters.

This paper describes the preparation of a new type of branched vegetable oil and its methyl ester that involves the formation of acetonides. A facile and environmentally friendly synthesis has been found to produce acetonides that entails the use of ferric chloride as a catalyst and is conducted at room temperature. The products have been fully characterized with the help of model compounds, including elemental analysis, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR), and gas chromatography-mass spectrometry (GC-MS).

Microwave-Assisted Synthesis and Characterization of Polyurethanes from TDI and Starch

In this work, a microwave-assisted method was developed to prepare polyurethanes from starch or maltodextrin and tolylene-2,4-diisocyanate (TDI). As compared to conventional heating, this new synthetic procedure saves energy, significantly reduces reaction time, and yet entails product yields that are comparable to those of the conventional heating procedure. The reaction products were characterized with NMR, FT-IR, thermogravimetric analysis, and scanning electron microscopy. From these analyses, the polyurethanes made with the conventional and microwave methods are shown to be similar in chemical structure and physical morphology. Furthermore, the 1H and 13C NMR spectra of the starch polyurethanes have been fully assigned for the first time.