Improving the yield of Jatropha curcas's FAME through sol–gel derived meso-porous hydrotalcites

The conversion of fatty acid methyl ester (FAME) from triglycerides using heterogeneous catalysis has gained increasing interest due to the prospect of increased yield at reduced operating costs and reaction conditions. In this paper, meso-porous hydrotalcite was used to catalyze jatropha oil into FAME with relatively higher yield at atmospheric pressure and relatively low reaction temperature. The molar ratio of methanol to oil required was relatively low and the conversion was completed within few hours of reaction time. The reaction was promoted when moderate calcination temperature was applied, the disordered structure of the catalyst was maintained, counterbalance anions was removed, and phase transitions within the oxide lattice was induced. Despite the observed deactivation during successive reaction cycles due to adsorption of residual triglycerides, the catalyst performance was restored effectively by air-re-calcination.     

The stability of vitamin A in fortified palm olein during extended storage and thermal treatment

The stability of vitamin A in Refined Bleached Deodorised Palm Olein (RBDPOL) was studied for 24 months. Vitamin A decreased with time, temperature and thermal treatment (frying/cooking). RBDPOL fortification was observed over several temperature ranges, using PET, nylon and HDPE commercial packaging materials. After 24 months, the following vitamin A contents of 39–43 IU g^?1 (39–45%) at 16–20 °C; 35–40 IU g^?1 (43–49%) at 24–29 °C; and 28–39 IU g^?1 (45–73%) at 24–45 °C were detected at the respective temperature ranges. Results showed stability of vitamin A fortified RBDPOL vegetable oil was not stable over typical shelf life (12 months). Depletion of vitamin A accelerated when the RBDPOL vegetable oil was subjected to high temperature thermal treatment.     

FT-RAMAN CHARACTERIZATION OF METHYL ACRYLATE-ETHYL ACRYLATE COPOLYMERS

Vibrational spectra of a series of Methyl Acrylate/Ethyl Acrylate (MA/EA) copolymers, synthesized at 60°C and 70°C for 5 different MA/EA compositions for each temperature, were obtained by FT-Raman spectroscopy. An inversion of the symmetric and antisymmetric stretching vibrations of the CH₃ group, due to the mobility of this group, was found. By analyzing the acoustical and optical branches of the spectra, the mobility of the backbone structure was also determined. The EA homopolymer was found to posses the highest conformational order.     

甲基丙烯酸甲酯/丙烯酸丁酯的无皂乳液共聚

以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为主要原料,过硫酸铵为引发剂,进行无皂乳液聚合.结果表明:在不添加乳化剂的情况下,当MMA/BA=1:1、引发剂用量为0.24%、反应温度为80℃、反应时间8.0h时,所得乳液最稳定,单体转化率为81.84%,此无皂乳液对牛皮纸的粘接性比常规乳液好.     

百草枯催吐剂三氮唑嘧啶酮的合成

甲基丙烯酸甲酯经溴化加成、醚化、催化裂化得3-甲氧基-2-甲基丙烯酸甲酯;单氰胺与二硫化碳在碱性条件下缩合、甲基化得氰亚胺基二硫代碳酸二甲酯,后与正丙胺缩合再与水合肼环合得氨基正丙胺基三氮唑,与苯甲醛醛缩合得醛缩物,再在缚酸剂下与3-甲氧基-2-甲基丙烯酸甲酯催化闭环后在盐酸中水解、去醛基得目标物。选择cat1#/2#为裂解和闭环催化剂,反应总收率达55.4%,产品纯度99.5%。     

Synthesis of well-defined star-branched polymers by stepwise iterative methodology using living anionic polymerization

This article reviews the synthesis of regular and asymmetric star-branched polymers with well-defined structures by methodologies using living anionic polymerization, especially focusing on the synthetic approaches accessible for precisely controlled architectures of star-branched polymers concerning molecular weight, molecular weight distribution, arm number, and composition. The reason for selecting living anionic polymerization from many living/controlled polymerization systems so far developed is that this living polymerization system is still the best to meet the strict requirements for the precise structures of star-branched polymers. Furthermore, we herein mainly introduce a novel and quite versatile stepwise iterative methodology recently developed by our group for the successive synthesis of many-armed and multi-compositional asymmetric star-branched polymers. The methodology basically involves only two sets of the reaction conditions for the entire iterative synthetic sequence. The reaction sequence can be, in principle, limitlessly iterated to introduce a definite number of the same or different polymer segments at each stage of the iteration. As a result, a wide variety of many-armed and multi-compositional asymmetric star-branched polymers can be synthesized.     

The Cost Evaluation of Advanced Oxidation Processes in Laboratory and Pilot-Scale Experiments

The present level of the development of water/wastewater treatment methods, including advanced oxidation processes, allows removal of pollutants of wide spectrum under no question. However, the overall process cost and, especially, associated energy consumption are of increased importance. The present review presents the energy cost calculations made for the pollutants removal reported in more than forty publications for over the last four decades. Phenol, glycols, methyl-tert-butyl ether (MTBE), aliphatic unsaturated compounds, humic acids and lignin were considered as water pollutants for economic evaluation of their removal. Two oxidation processes, ozonation and Fenton reaction, were chosen as water treatment methods.     

Fabric electrodes coated with polypyrrole nanorods for flexible supercapacitor application prepared via a reactive self-degraded template

Wearable energy storage devices that can be used in the garment industry are strongly required to power E-textiles. In this article, polypyrrole (PPy) nanorods were deposited on cotton fabrics via in situ polymerization of pyrrole in the presence of the fibrillar complex of FeCl₃ and methyl orange as a reactive self-degraded template. The obtained fabrics could be directly used as supercapacitor electrodes, with a maximum specific capacitance of 325 F g⁻¹ and an energy density of 24.7 Wh kg⁻¹ at a current density of 0.6 mA cm⁻². The capacitance remained higher than 200 F g⁻¹ after 500 cycles.     

稀土固体超强酸SO42-/SnO2- Nd2O3催化合成棕榈酸甲酯

采用溶胶-凝胶法制备稀土固体超强酸催化剂SO4-/SnO2- Nd2O3,以工业棕榈酸和甲醇为原料催化合成棕榈酸甲酯.考察了氧化钕添加量、焙烧温度、硫酸浓度、醇酸质量比、催化剂用量和反应时间对酯化反应的影响.结果表明,当氧化钕添加量为5％,以2.0 mol/L硫酸浸渍后,于550℃下焙烧3h制备的催化剂性能最好.正交实验结果表明,合成棕榈酸甲酯的优化条件为:醇酸质量比为15∶25,催化剂用量为棕榈酸质量的6.0％,反应时间5h.在此条件下,酯化率为90.1％.     

油酸甲酯和硬脂酸甲酯热解特性及动力学研究

通过热重分析仪对油酸甲酯和硬脂酸甲酯的热解特性进行了研究,发现油酸甲酯相变硬脂酸甲酯具有较差的热安定性。在升温速率分别为10、15、20、30℃/min条件下,利用TG-DTG曲线分析了它们的基本热解特性。结果表明,随着升温速率的增加,它们的起始热分解温度、最大失重速率、最大失重速率峰值温度以及其他热分解参数均呈增大趋势。同时,用多元线性回归法求得相应的反应级数、活化能和指前因子,发现油酸甲酯和硬脂酸甲酯的热解反应机理函数不同,且反应活化能和指前因子之间表现出较好的动力学补偿效应。