Volume phase transition behavior of N‐isopropyl acrylamide–N‐cyanomethyl acrylamide copolymer gel particles: The effect of crosslinking density

We prepared submicron‐sized N‐isopropyl acrylamide (NIPA)–N‐cyanomethyl acrylamide (NCMA) copolymer gel particles by precipitation polymerization. Volume phase transition behaviors of gel particles with various compositions and crosslinking density were observed by using photon correlation spectroscopy (PCS). The experimental data showed that both the volume transition temperature and the swelling ratio of copolymer gel particles were varied with the mole ratio of NCMA and NIPA. We compared the swelling behaviors of given systems with the thermodynamic model based on the extended Flory–Huggins theory. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1091–1099, 1999     

离子液体催化合成异丙苯的研究

以氯化正丁基吡啶-三氯化铝（bpc—AlCl3）离子液体为催化剂。考察了离子液体催化荆的酸度、反应温度、苯与丙烯的摩尔比、反应时问等因素对苯与丙烯烷基化反应的影响。结果表明：酸性离子液体具有较高的催化活性与选择性,并且离子液体的活性与其酸度密切相关,酸度越大,离子液体的催化活性越好。在50％、常压、苯与丙烯的摩尔比为10、AlCl3与bpc的摩尔比为2时,丙烯转化率为100％,异丙苯选择性为97．56％,并且离子液体可以循环使用。     

异丙醚-异丙醇-水三元共沸物的Aspen Plus分离模拟

以乙二醇为溶剂,使用Aspen Plus化工模拟软件中的BatchFrac模块,基于UNIFAC模型,对异丙醚-异丙醇-水三元共沸物的间歇萃取精馏过程进行间歇萃取精馏模拟,研究了不同操作参数（如溶剂比、回流比、溶剂进料位置、溶剂进料温度等）对整个精馏过程的影响,对各工艺参数进行了分析与优化。结果表明,对于处理量为100kmol的异丙醚-异丙醇-水溶液,精馏塔具有16块塔板时,溶剂进料位置在第3块塔板,溶剂进料温度为60℃,异丙醚收集阶段回流比为5,溶剂比为1.72∶1,异丙醇收集阶段回流比为5,溶剂比为0.63∶1,塔顶异丙醚质量分数可达0.996,异丙醇质量分数可达0.978。     

A study of digital image analysis on the acrylamide derivative monomers induced apoptosis in rat cerebrum

Nowadays, apoptosis is mostly evaluated visually in histological studies. By using the quantitative digital image analysis, this study aimed to investigate the effect of acrylamide‐based monomers (acrylamide [AAm], methacrylamide [MAAm], N‐isopropylacrylamide [NIPAm]) on the cerebrum tissues in rats, which are the most common water‐soluble monomers in the production of polymeric hydrogels used as biomaterials. The Wistar albino rats weighing ~220–240 g were divided into control and three test groups. The control group received 1 mL of saline, and the test groups received 1 mL of aqueous 50 mg/kg/day intramuscular injection of AAm, MAAm, and NIPAm, respectively. At the end of the experiments, brain tissues of all rats euthanized by intramuscular injection of sodium pentobarbital were removed. Terminal deoxynucleotide transferase dUTP nick and labeling (TUNEL) method was applied to brain tissue sections. The monomers have been shown to cause apoptosis due to oxidative stress in cerebrum tissue. Based on apoptosis by tunneling method, quantitative digital image analysis of cell fragments was performed with Olympus cellSens Dimension 1.15 software, and the number, total count area, selected area, average area, and ROI% values of the fragments were found. In addition, the total area and ROI% values of the fragments increased linearly with increasing the molar mass of monomers from the digital image analysis data. Quantitative digital image analysis can facilitate the monitoring of apoptosis caused by the oxidative stress of monomers used in the production of the biomaterials.     

超纯异丙醇的制备方法研究

进行了通过前处理后在精密分馏的制备C12标准的异丙醇的方法研究,得到了合格的产品,为工业化生产打下了基础。     

Evaluation of sequential methods for the determination of butterfat fatty acid composition with emphasis ontrans-18:1 acids. Application to the study of seasonal variations in french butters

The successive steps of an integrated analytical procedure aimed at the accurate determination of butterfat fatty acid composition, includingtrans-18:1 acid content and profile, have been carefully checked. This sequential procedure includes: dispersion of a portion of butter in hexane/isopropanol (2:1, vol/vol) with anhydrous Na₂SO₄, filtration of aliquots of the suspension through a microfiltration unit, subsequent preparation of fatty acid isopropyl esters (FAIPE) with H₂SO₄ as a catalyst, and analysis of total FAIPE by capillary gas-liquid chromatography (GLC). Isolation oftrans-18:1 isomers was by silver-ion thin-layer chromatography (Ag-TLC), followed by extraction from the gel of combined saturated andtrans-monoenoic acids with a biphasic solvent system. Analysis of these fractions by GLC allows the accurate quantitation oftrans-18:1 acids with saturated acids (14:0, 16:0, and 18:0) as internal standards. A partial insight in the distribution oftrans-18:1 isomers can be obtained by GLC on a CP Sil 88 capillary column (Chrompack, Middelburg, The Netherlands). All steps of the procedure are quite reproducible, part of the coefficients of variation (generally less than 3%, mainly limited to butyric and stearic acids) being associated with GLC analysis (injection, integration of peaks) and, to a lesser extent, to FAIPE preparation. FAIPE appear to be of greater practical interest than any other fatty acid esters, including fatty acid methyl esters (FAME), for the quantitation of short-chain fatty acids, because peak area percentages, calculated by the integrator coupled to the flame-ionization detector, are almost equal (theoretically and experimentally) to fatty acid weight percentages and do not require correction factors. With this set of procedures, we have followed in detail the seasonal variations of fatty acids in butterfat, with sixty commercial samples of French butter collected at five different periods of the year. Important variations occur around mid-April, when cows are shifted from forage and concentrates during winters spent in their stalls to fresh grass in pastures. At this period, there is a decrease of 4:0–14:0 acids and of 16:0 (−2 and −6%, respectively), while 18:0 andcis- plustrans-18:1 acids rise suddenly (2 and 5%, respectively). These modifications then progressively disappear until late fall or early winter. Other variations are of minor quantitative importance. Although influenced by the season, the content of 18:2n-6 acid lies in the narrow range of 1.2–1.5%.Trans-18:1 acids, quantitated by GLC after Ag-TLC fractionation, are at their highest level in May–June (4.3% of total fatty acids), and at their lowest level between January and the end of March (2.4%), with a mean annual value of 3.3%. The proportion of vaccenic (trans-11 18:1) acid, relative to totaltrans-18:1 isomers, is higher in spring than in winter, with intermediate decreasing values in summer and fall, which supports the hypothesis that the level of this isomer is linked to the feed of the cattle, and probably to the amount of grass in the feed.     

甲烷磺酸镧在酯化反应中的催化活性

合成了甲烷磺酸镧,用红外、热重分析对其进行表征。热重分析结果表明所合成的甲烷磺酸镧分子中含四个结晶水,La2O3含量的实测值与理论计算值基本相符。以甲烷磺酸镧为催化剂,研究了其催化氯乙酸与异丙醇酯化反应中各种因素对酯化率的影响。反应条件为:醇酸摩尔比1.2∶1,催化剂用量1.0%(以酸的摩尔数计量),反应时间2.5h,反应温度为回流温度,苯作为带水剂,最高酯化率可达95.5%。与其它Lewis酸催化剂比较,甲烷磺酸镧的催化活性最好。     

乙酸异丙酯合成研究进展

综述了乙酸异丙酯的合成方法 ,详细介绍了以不同原料、不同催化剂、不同工艺合成乙酸异丙酯的技术进展。     

甲基异丙酮的合成技术及市场分析

介绍了甲基异丙酮的多种合成路线,主要有异丁醛-乙酸法、异丁酸-乙酸法、甲基乙基酮-甲醛法和异戊二烯法。概述了国内外甲基异丙酮的的开发和生产现状,并分析了国内市场现状,最后对我国甲基异丙酮今后的发展方向提出了几点建议。