乙酰柠檬酸三丁酯的合成

用柠檬酸、正丁醇、乙酸酐为原料，经酯化和酰化两步反应合成乙酰柠檬酸三丁酯。考察了催化剂、原料配比、反应温度和反应时间等因素对合成反应的影响，确定了最佳反应条件。     

Barley Protein Isolate: Thermal, Functional, Rheological, and Surface Properties

Barley protein isolate (BPI) was extracted in 0.015 N NaOH in a 10:1 ratio solvent:flour and was precipitated by adjusting the pH to 4.5 and freeze-dried. The thermal properties of BPI were determined using modulated differential scanning calorimetry (MDSC). BPI with 4% moisture content exhibited a glass transition (T _g) with 140 °C onset, 153 °C middle, and 165 °C end temperatures and a ΔC _p of 0.454 J/g per °C. The high moisture content sample (50%) showed a T _g at 89, 91, or 94 °C and 0.067 ΔC _p. Acetylation had no apparent effect on the foaming and emulsifying properties of protein from barley flour but exhibited the least-stable foam among BPI samples. Foaming capacities of both barley protein isolates were ∼12% less than that of acid-precipitated soy protein isolate reported in the literature. Acetylated BPI showed the highest surface hydrophobicity compared to the other samples. The surface-tension test confirmed that unmodified and modified BPI possessed surface activity. BPI phosphorous oxycloride-crosslinked was the most effective in lowering the surface tension of aqueous NaCl, while the crosslinked BPI was the least effective. The G′ value of BPI suspension was greater than G″ at all frequencies from 0.1 to 100 rad/s. The strain value at which linear behavior ceased and nonlinear behavior began ranged from 3 to 10%. Names are necessary to report factually on available data; however, the United States Department of Agriculture (USDA) neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable.     

过磷酸（SPA）可用作柏木烯乙酰化作用的催化剂

本文论述经实验和四年多出产实践证明 ,过磷酸 (SPA)可用作柏木烯乙酰化作用的催化剂。在甲基柏木酮(MCK)合成工艺中 ,与多聚磷酸 (PPA)催化剂相比 ,过磷酸有直接使用和方便之优点 ,并能改善劳动条件 ,而且过磷酸催化剂的成本略低于多聚磷酸催化剂     

柠檬酸三丁酯、乙酰柠檬酸三丁酯合成工艺的研究

以柠檬酸、正丁醇为原料，采用直接酯化法合成了柠檬酸三丁酯。以柠檬酸三丁酯、乙酐和正丁醇为原料，采用共乙酰化-酯化法合成出乙酰柠檬酸三丁酯，并联产乙酸正丁酯。考察了催化剂用量、原料配比、反应温度、反应时间等因素对反应过程的影响，确定了较佳的操作条件，柠檬酸三丁酯收率≥98％，乙酰柠檬酸三丁酯收率≥98％。采用活性炭脱色技术对产品进行精制，明显改善了产品的色泽。     

A Note on the Effect of Microwave Heating on Iodine-Catalyzed Acetylation of Wood

The effect of microwave heating on the iodine-catalyzed acetylation of rubberwood with acetic anhydride has been investigated. Microwave radiation was used as the heating source for modifying specimens saturated with acetic anhydride in bulk solution (excess of reagent) and impregnated specimens (limited supply of anhydride). Extent of modification of wood was expressed in terms of weight percent gain (WPG) and modification was characterized using FTIR spectroscopy. In bulk solution, microwave radiations were primarily absorbed by anhydride solutions for heating purposes and a moderate WPG was obtained. However, when microwave heating was used to modify impregnated wood specimens under no excess of anhydride, a significant enhancement in degree of modification was achieved within a few minutes. The modified wood exhibited good anti-swelling efficiency.     

Sulfonated charcoal as a mild and efficient catalyst for esterification and trans-esterification reactions

Sulfonated charcoal was found to be an efficient heterogeneous catalyst for the acetylation of alcohols in acetic acid. Esterification of different carboxylic acids with different alcohols was also achieved with this catalyst. Acetylation and formylation of alcohols can also be catalysed efficiently in ethyl acetate and ethyl formate in high yields.     

Moisture barrier and physical properties of acetylated derivatives with increasing acetylation degree

Four acetostearin products with increasing acetylation degree were synthesized by chemical interesterification followed by fractionation/blending stages. Their physical properties and functional barrier properties were studied and compared to the properties of technical tristearin. Increasing acetylation degree (AD) modified the triacylglycerols crystal habits and probably led to an increase in acyl chain fluidity, which induced, at macroscopic levels, a decrease in solid fat content (SFC), in melting point, in surface and bulk material hydrophobicity, and an increased moisture effective diffusivity. Water vapor permeability (WVP) coefficients of the materials were partially influenced by the AD factor, but also by the development of macroscopic cracks in lipids presenting high SFC. Acetylated stearin up to 47% (acetyl mol/mol of esterified chain) presented the lowest WVP at 20 °C resulting from an adequate balance between hydrophobicity and mechanical properties of the material.     

Acetylation of glycerol to synthesize bioadditives over niobic acid supported tungstophosphoric acid catalysts

Acetylation of glycerol to yield mono, di and triacetin (acetylated glycerol) was carried over niobic acid supported tungstophosphoric acid (TPA) catalysts. The catalysts with varying TPA content were prepared and characterized by different techniques. The characterization results reveal the presence of well-dispersed Keggin ion on support. The results suggest that the glycerol conversion and selectivities depend on the acidity of the catalysts, which in turn is related to the content of TPA on niobic acid. The change in conversion and selectivities during the acetylation also is attributed to the reaction time, catalyst concentration and glycerol to acetic acid molar ratio.     

烟用二醋酸纤维生产过程中飞花的定性表征

为研究烟用二醋酸纤维生产过程中的飞花及其产生机理,采用多角激光散射检测器与凝胶渗透色谱联用、差示扫描量热和电子扫描电镜等方法对飞花进行了表征。结果表明,分子量及其分布、醋酸纤维素的合成过程、纺丝浆液中的凝胶组分和二氧化钛颗粒以及纺丝工艺条件的波动等是造成飞花的主要因素。