A potential pentaerythritol-based bio-lubricants from 10-undecylenic acid: Its physico-chemical assessment

In this study, renewable, non-toxic, sulphur free bio-lubricants are synthesized as alternative for fossil fuels. We utilized a bio-derived 10-undecylenic acid (UDA) and pentaerythritol (PE) as raw materials to synthesize bio-lubricants by two-step chemical processes like esterification and followed by epoxidation reactions. And achieved a UDA-PE epoxide yielded 73.4%. The formation of UDA-PE ester and UDA-PE epoxide was confirmed by spectral analysis such as NMR (¹H and ¹³C), FTIR and mass spectra, Physico-chemical and basic lubricant properties by standard American Society for Testing and Materials methods (ASTM). The results showed that the products of UDA-PE ester and UDA-PE epoxide had high viscosity index (262 and 200), good pour points (−29 °C to −15 °C), high flash points (296 °C and 301 °C) respectively and these met the ISO VG (International Organization for Standardization-Viscosity grade) 22 and 220 standard values. In general, both synthesized products are plausible to be employed as bio-lubricant in industrial application.     

Process intensification for synthesis of triglycerides of capric acid using green approaches

The present research focuses on intensified synthesis of tricaprin by esterification reaction between capric acid and glycerol catalysed by dry amberlyst-15 using ultrasonication approach. Effect of several reaction conditions like molar ratio, reaction temperature, and amberlyst-15 loading on the rate of conversion has been studied. Effect of ultrasonic conditions like duty cycle and irradiation time on the intensified synthesis is investigated. Recyclability of amberlyst-15 is studied to make process more economical. It is investigated that the optimum reaction conditions which gave maximum conversion of 95% were molar ratio of capric acid: glycerol as 3:5, reaction temperature 90 ​°C, 4% amberlyst −15 loading. It was further investigated that ultrasonic conditions which gave intensified synthesis were 70% duty cycle and irradiation time of 120 ​min. The ultrasonic assisted process was compared with conventional synthesis. Conventional synthesis gave 30% yield in 120 ​min and 82% in 18 ​h. Amberlyst-15 was successfully reused for 13 cycle without any change in the conversion (%) of reaction.     

Esterification of Oleic Acid to Produce Biodiesel over 12-Tungstophosphoric Acid Anchored Two-dimensional Zeolite

Biodiesel has emerged as a non-toxic, biodegradable, and renewable fuel substitute that can be readily produced via the esterification reaction of free fatty acids. The present work explores the potential of 12-tungstophosphoric acid(TPA) anchored two-dimensional(2D) ITQ-2 zeolite(TPA/ITQ-2) as heterogeneous acid catalysts for biodiesel production. TPA/ITQ-2 material was prepared by swelling, delamination, and subsequent wetness incipient impregnation approach. The prepared catalysts were comprehensively characterized by powder X-ray diffraction, N₂ adsorption/desorption, temperature-programmed desorption of ammonia, flou-rier transform infrared spectroscopy, and transmission electron microscopy. The catalytic activity of TPA/ITQ-2 for biodiesel production was evaluated by the esterification reaction of oleate acid with methanol. Process parameters, such as reactant molar ratio and TPA loading were optimized. Due to the superior mass transfer and adequate stable acid sites, 2D TPA/ITQ-2 showed a higher catalytic activity and a better recyclable stability than the 3D and layered TPA/zeolites. This work will provide new opportunities for the design of 2D zeolite-based acid catalysts for biodiesel production.     

Production of biofuel additives by esterification and acetalization of bioglycerol

The current transition from petrochemical resources to biomass-derived platform molecules is in great demand for the development of synergies, scientific innovations and breakthroughs, and steep changes in the infrastructure of chemical industries. This article is focused on new opportunities for the production of biofuel additives from bioglycerol, which is obtained as waste and/or by-product from the current biodiesel industries. Here, we summarize the recent relevant processes for the production of biofuel additives from bioglycerol over various acid catalysts in two different pathways: (i) the esterification of bioglycerol with acetic acid, levulinic acid and other acids, and (ii) the acetalization of bioglycerol with acetone, furfural, benzaldehyde and other carbonyl compounds. It is evident that the synthesis of biofuel additives through esterfication and acetalization of bioglycerol is an important research area with imperative prospects for industrial applications.     

Convenient Esterification of Carboxylic Acids by SN2 Reaction Promoted by a Protic Ionic-Liquid System Formed in Situ in Solvent-Free Conditions

The reaction of esterification of benzoic acid with benzyl chloride was chosen as a model reaction to study the esterification by S_N2 promoted by tertiary amine as deprotonating agent. The use of ionic liquid (IL) 1,3-dimethylimidazolium methanesulfonate [MMIm][OMs] as reaction medium has proven to give quantitative yield of the ester, but interestingly the reaction does occur even in solvent-free conditions, where the acid + the amine form a liquid system (a protic IL) in situ. This last methodology was extended to several carboxylic acids in conditions of atom economy (i.e., without excess of any reagent), giving moderately good yields of esters (54–78%) recovered by weight in pure form.     

Microwave-assisted lipase-catalyzed synthesis of polyethylene glycol stearate in a solvent-free system

Polyethylene glycol stearate, a condensation esterification product of stearic acid and polyethylene glycol 600, was widely applied in the biomedical and healthcare industries. The current work focuses on the enzymatic synthesis of PEG stearate using CALB_ex10000, a commercial Lipase enzyme in solvent-free conditions using microwave irradiation. The influence of various reaction parameters such as temperature, molar ratio of reactants, and enzyme loading was studied to obtain the highest conversion. Maximum conversion of 85% was attained under molar ratio 1:1 (PEG 600 to stearic acid using 0.7% (w/w) enzyme loading at 60 ​°C of temperature in 70 ​min of reaction time. Further, the thermodynamic parameters were analyzed and compared with the conventional and ultrasound-assisted synthesis of PEG stearate. The enzyme was recycled up to 5^th cycle giving more than 35% of the initial activity.     

A Nonenzymatic Kinetic Resolution of (±)-trans-2-Arylcyclohexanols via Esterification Using Polymer-Supported DCC,DMAP, and 3β-Acetoxyetienic Acid

A nonenzymatic kinetic resolution of (±)-trans-2-arylcyclohexanols was carried out by esterification using polymer-supported N,N′-dicyclohexylcarbodiimide (DCC), dimethylaminopyridine (DMAP), and 3β-acetoxyetienic acid. The efficiency of the kinetic resolution was comparable to the enzymatic method when arylcyclohexanols bearing a condensed-aromatic ring were used.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communication® to view the free supplemental file.     

Dabco-Catalysed Reactions of Salicylaldehydes with Acrylate Derivatives

Treatment of salicylaldehydes with acrylate derivatives in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) has been shown to afford both coumarin and chromene derivatives, and factors influencing the product distributions have been investigated.     

Toggle-switchable fluorescence of bisindolylmaleimide derivatives by reversible esterification/hydrolysis

Isomers based on the bisindolylmaleimide architecture were reported in this Letter. Introducing hydroxyl to this architecture lead to quenching the fluorescence of bisindolylmaleimide. The fluorescence was recovered with its hydroxyl group esterified. Ester group can be easily transformed to hydroxyl group by hydrolysis reaction. Thus, a toggle-switchable fluorescence, ‘off-on’ cycle can be established on the basis of reversible esterification/hydrolysis reaction.     

11-钨锌三元杂多阴离子层状化合物的合成、表征及催化活性

用离子交换法将具有K egg in结构11-钨锌三元杂多化合物K8[M ZnW11（H2O）O39]（M=Co2＋、N i2＋、Cu2＋、Cd2＋）嵌入到Zn2A l类水滑石中,得到层状化合物：Zn2A l-[M ZnW11（H2O）O39]（M=Co2＋、N i2＋、Cu2＋、Cd2＋）,并用XRD、IR、UV对其进行了表征。结果表明,杂多阴离子进入水滑石层间后,仍保留了其K egg in结构。利用层状化合物催化合成乙酸正丁酯考察其催化活性,结果表明,层状化合物在酯化反应中显示优良的催化性能。