Neeraj Atray

Derivatizing L-histidine to develop a novel additive for a polyol-based biolubricant

Two novel histidine Schiff base esters, HSE-A and HSE-B, were synthesized using a two-step reaction. The synthesized compounds were characterized using carbon, hydrogen, nitrogen analysis, Fourier-transform infrared and nuclear magnetic resonance spectroscopy. The antioxidant and anticorrosion properties of these additives were assessed using the universal oxidation test (IP-306) and standard accelerated corrosion testing procedure, which revealed that both additives have good antioxidant and anticorrosion properties. Lubricity test carried out in a four-ball test machine indicated that both additives could reduce wear when compared with the pure polyol base oil. Overall, the HSE-A additive is more effective than the HSE-B additive as an antioxidant/antiwear/anticorrosion biolubricant additive.

Development of new ecofriendly detergent/dispersant/antioxidant/antiwear additives from L-histidine for biolubricant applications

Two novel overbased Ca salts of histidine Schiff base esters Ca-HDS-L and Ca-HDS-M were synthesized following a three-step reaction sequence. The histidine Schiff base (HDS) was synthesized first by imine coupling of histidine with salicylaldehyde. Then its phenolic group was esterified using lauroyl chloride and myristoyl chloride to obtain HDS-L and HDS-M, respectively. Finally in the third step, their respective overbased salts Ca-HDS-L and Ca-HDS-M were synthesized by reaction with Ca(OH)2. All the synthesized compounds were characterized using FT-IR, NMR, CHN and TG analysis. Panel coker federal test (FTM 3462), blotter spot test (ASTM D7899), universal oxidation test (IP-306) and four ball test (ASTM 4172A) were used for the evaluation of detergent, dispersant, antioxidant and antiwear activity, respectively, of the synthesized additives in polyol base oil. Both the additives are active but overall Ca-HDS-L is more effective as detergent and dispersant while Ca-HDS-M is more effective as antioxidant and antiwear multifunctional biolubricant additive.

Capacity of thiourea Schiff base esters as multifunctional additives: synthesis, characterization and performance evaluation in polyol

A novel thiourea Schiff base ester TSBE was synthesized following a two step reaction. At first, thiourea and salicylaldehyde were reacted in ethanol to obtain thiourea Schiff base TSB. In the second step, esterification of TSB was done with lauroyl chloride catalyzed by 4-(dimethylamino)pyridine (DMAP) in N,N-dimethylacetamide (DMAc) solvent to obtain the final product TSBE. The synthesized compounds were characterized using CHN analysis, FT-IR and NMR. The antioxidant properties of this additive were assessed via the universal oxidation test (IP-306) and rotary bomb oxidation test (ASTM D2272) while antifriction and antiwear properties were evaluated in terms of the average friction coefficient and average wear scar diameter respectively by doing the four ball test (ASTM D4172). Studies revealed that TSBE had good antioxidant properties. Tests carried out by a four ball test machine indicated that the additive TSBE could reduce the friction to 45.6% and wear to ∼20% when compared with the pure polyol base oil.

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.

Synthesis of a novel efficient antioxidant for use in lubes and biodiesel

A novel phenolic ester Bz-3-tBz was synthesized by reaction between 1,3,5-benzenetricarboxylic acid chloride and 3,5-di-tert-butyl-4-hydroxybenyl alcohol using N,N’-dimethylacetamide solvent and N,N’-dimethylaminopyridine as catalyst. The additive Bz-3-tBz was characterized by CHN, FT-IR, NMR and TG. The Bz-3-tBz was then evaluated as antioxidant additive in polyol by the rotatory bomb oxidation test (RBOT) as per ASTM D2272. The RBOT time for the blank sample containing only polyol base was observed to be 6 min 43 sec. It was observed that Bz-3-tBz in 3000 ppm concentration enhanced the RBOT time to the 15 min 46 sec. It was a significant increase of 2.35 times. The oxidation stability of biodiesel was also found to be increased when Bz-3-tBz was added in to it. The value of induction time determined by the Rancimat test for the biodiesel at 130°C was 0.60 h which was increased to 3.14 h at 2000 ppm Bz-3-tBz concentration.

Enhanced biomass production of Scenedesmus obliquus in a flat-panel photobioreactor, grown in photoautotrophic mode

ABSTRACT A study on biomass accumulation was conducted with Scenedesmus obliquus CCAP 276/3A in flat-panel photobioreactor, grown in photoautotrophic mode. It is one of the prime prerequisites to increase the economic feasibility and acceptance of microalgal feedstock for biofuel production, besides high lipid concentration. Various physicochemical parameters considered for evaluation during the present study were illumination conditions between 50 and 200 µmol m−2 s−1, temperatures between 22 and 30°C, pH varying from 7 to 9, and with and without the use of buffers. Among the variables, growth temperature and buffering with TRICINE had a pronounced effect on the enhanced biomass production. With an illumination intensity of 150 µmol m−2 s−1 at 24°C in the TRICINE-buffered Bolds Basal medium (pH 8.5) the maximum biomass concentration achieved was 1.76 gL-1. The specific growth rate of the microalga was found to be 1.28 d−1. Under these optimized conditions, the maximum lipid accumulation in Scenedesmus obliquus was found to be 33% (w/w). The compositional analysis of the neutral lipids indicated the predominance of palmitic acid and linoleic acid, accounting for 28% and 22.5%, respectively.