蓖麻酸正丁酯的催化合成研究

用NaHSO4.H2O作催化剂,对蓖麻酸与正丁醇酯化反应进行了研究。在回流温度(油浴温度145~150℃)下,分别考察了催化剂用量、醇酸摩尔比、反应时间对酯化反应的影响。得出的优化工艺条件为:催化剂用量1.01%(催化剂与蓖麻酸的质量比)、醇酸摩尔比2.5(蓖麻酸0.2mol)、反应时间2h。在该工艺条件下,蓖麻酸的平均酯化率可达95%。红外光谱表明:反应过程蓖麻酸中的羟基和双键保存完好,催化剂表现出了很好的活性和很高的选择性。该方法的产物后处理工艺简单且不污染环境。     

Comment on the paper by J. Thomas Joseph Prakash, S. Kumararaman, “Growth and characterization of l-asparagine thiourea monohydrate (LATM): A nonlinear optical single crystal”, Materials Letters 62(2008) 4003-4005

It is argued that the conclusion of the authors of the title paper on obtaining of a new crystal l-asparagine thiourea monohydrate is erroneous. The authors actually have obtained well known l-asparagine monohydrate crystal.     

Synthesis of zeolite Li-ABW from fly ash by fusion method

The zeolite Li-ABW was synthesized by fusion method using fly ash as raw material. It comprised alkaline fusion followed by hydrothermal treatment in LiOH·H₂O medium. Crystallinity of zeolite as high as 97.8% was attained under the following conditions: LiOH·H₂O concentration, 3 M; hydrothermal temperature, 180 °C; the corresponding aging time, 12 h. The content of Li-ABW increased at the expense of lithium aluminum silicate or quartz with an increase of LiOH·H₂O concentration. With increasing hydrothermal temperature and aging time, the soluble species re-crystallized and crystalline phase transformation between different zeolites was observed. Scanning electron microscopy (SEM) observation revealed that the obtained zeolite Li-ABW was a rod-like crystal. The pore size distribution curve indicated the presence of mesopores.     

利用七水硫酸亚铁生产一水硫酸亚铁及聚合硫酸铁

钛白粉生产中副产大量的七水硫酸亚铁,采用合理工艺可以同时生产饲料级一水硫酸亚铁和水处理剂聚合硫酸铁,并实现废水零排放。     

硫酸氢钠催化合成马来酸二乙酯

在一水硫酸氢钠存在下,马来酸酐与乙醇反应合成马来酸二乙酯。当马来酸酐、乙醇和一水硫酸氢钠的摩尔比为1∶4∶0.36、环己烷为溶剂、回流分水40 min时,酯产率可达74.4%。利用折射率、元素分析和红外光谱对酯进行了表征。     

基于N-甲基吗啉-N-氧化物溶剂制备聚芳砜酰胺/纤维素阻燃纤维

为制备兼具阻燃和吸湿性能的纤维,采用N-甲基吗啉-N-氧化物(NMMO)水溶液为共溶剂,分别将纤维素(cellulose)和聚芳砜酰胺(PSA)溶解后进行共混制备纺丝液,通过干喷湿法纺丝制备PSA/cellulose共混纤维,并对纺丝液及共混纤维的结构和性能进行表征与分析。结果表明:NMMO对PSA具有良好的溶解性能,纺丝液均质、稳定,制备的共混纤维呈现出PSA富集于纤维表层的类皮-芯结构;PSA/cellulose纤维具有良好的阻燃性能、吸湿性能和力学性能,当纤维素质量分数达到30%时,共混纤维仍可达到阻燃纤维标准,其断裂强度为2.08 cN/dtex,无需后道牵伸处理就能达到较高的强度,此时PSA/cellulose纤维的回潮率提高为8%,具有良好的可染性。     

肌酸类运动营养品的研究现状及其对运动员的影响

随着竞技体育的快速发展,为了适应高强度、大运动量的训练和比赛,运动员需要摄入营养补充剂来维持运动能力以及恢复身体状态。而肌酸作为一种天然存在的非蛋白氨基酸化合物,可以转化为磷酸肌酸从而合成人体活动所必须的物质---ATP,进而快速提升能量,增加肌肉的爆发力和耐久力,提高身体素质和运动成绩。目前,肌酸已经成为在运动员和健身人群中使用最广泛的运动营养补充剂。故本文结合近些年国内外关于肌酸类运动营养品应用的研究,综述了肌酸的生理功能以及其在运动领域的作用机制,以期为肌酸类营养品在运动领域的研究提供一定的理论指导依据。     

Analysis of Morphological Changes in Monosodium Urate Monohydrate Crystals for Gout Treatment

Gout is arthritis induced by monosodium urate monohydrate (MSU) crystals. The treatment of gout is mainly a symptomatic treatment, by suppressing the blood uric acid concentration with drugs. Here, the changes in crystal morphology in the process of MSU crystallization were investigated. Experiments were conducted to clarify the mechanisms of nucleation and growth of the MSU crystals, revealing that MSU first precipitated as granular crystals. Thereafter, nucleation and growth of needle-like crystals were observed concomitant with the disappearance of the granular crystals. These results suggest that it is necessary to suppress the nucleation of granular crystals and the change in morphology from granular to needle-like of the MSU crystals that cause gout.     

利用粗镁生产精制一水硫酸镁的研究

根据MgSO_4-H_2O体系相图,提出了运城盐湖冬季大田结晶的粗硫酸镁生产精制—水硫酸镁的工艺流程,并对工艺条件进行了探讨和分析,最后指出该产品具有纯度高、呈中性、不含重金属杂质等优点。     

Creatine and creatinine evolution during the processing of dry-cured ham

Dry-curing of ham involves many biochemical reactions that depend on the processing conditions. The aim of this study was to evaluate the effect of the dry-cured processing on the concentration of creatine, creatinine and the creatinine/creatine ratio. Dry-cured hams under study were salted using three different salt mixtures (100% NaCl; NaCl and KCl at 50% each; and 55% NaCl, 25% KCl, 15% CaCl₂ and 5% MgCl₂) in order to observe its influence on creatinine formation but no significant differences were found between them at any time of processing. However, significant differences between different post-salting times (20, 50 and 80 days) and the ripened hams (7, 9 and 11 months of ripening) were observed. Results showed that creatine and creatinine remain stable once the ripening period is reached. These results were confirmed when analysing dry-cured ham samples submitted to extreme conditions of temperature and time (20, 30, 40 and 70 °C during 0, 20, 40 and 60 min) as well as commercial dry-cured hams with more than 12 months of processing.