Acetone transformation into methyl isobutyl ketone over Pt/HMFI catalysts. IV. Effect of density and strength of the acidic sites

Acetone transformation into methyl isobutyl ketone (MIBK) was studied using a fixed-bed dynamic reactor at 160°C, 1 atm pressure and acetone/H₂ molar ratio=3. The reaction was carried out over Pt/HMFI bifunctional catalysts, with 0.30 wt% of platinum which was supported over three aluminosilicates (Si/Al ratio=40, 95 and 160) and a borosilicate (Si/B ratio=44) with similar dispersion. The results show that catalytic properties depend greatly on density and strength of the acidic sites of the catalysts. Moreover, the limiting step of the MIBK synthesis reaction (aldolization of two acetone molecules) is carried out over the acidic sites of the aluminosilicates, but not over those of the borosilicate, which considerably affects reaction selectivity. This revised version was published online in July 2006 with corrections to the Cover Date.     

6-APA中残留丙酮、甲基异丁基酮的测定

采用直接进样色谱法测定,并用内标法（2-戊酮作内标物）定量,确定6-APA中残留丙酮、甲基异丁基酮的检测方法。经验证此法可准确测定6-APA中丙酮、甲基异丁基酮的残余量。     

微波辅助丙酮提取大蒜油工艺的研究

为提高大蒜油的得率,增加大蒜的附加值,采用微波辅助、丙酮提取的方法进行大蒜油提取工艺.通过单因素和正交试验考察微波的功率、大蒜和丙酮的配比、微波提取的时间和丙酮的浓度对大蒜油提取得率的影响.结果表明,大蒜和丙酮的配比为大蒜油提取工艺的最显著影响因素;最佳的工艺条件是,微波功率100 W、微波提取时间75 s、液料比25∶1、丙酮体积分数为90％时,大蒜油的提取率最高,提取率为3.85％.     

Modification of Crude Canola Lecithin for Food Use

Crude canola lecithin was fractionated by removal of neutral lipids with acetone followed by ethanol extraction with or without supercritical carbon dioxide (SC-CO₂). Two extraction steus of 60 min each at 35°C with 500 mL acetone were optimum for maximum yield of acetone solubles and maximum phospholipid (PL) concentration (66.7%) in the acetone insoluble (AI) fraction. AI were separated into 26.5% ethanol soluble and 68.7% ethanol insoluble fractions. PL concentration in the extract increased with increasing amounts of ethanol used. Yields were low for SC-CO₂/ethanol extraction, of which extracts from 55.2 MPa/ 70°C contained 32% PL (83% phosphatidyl choline).     

工业苯酚丙酮装置氧化尾气的气相色谱分析

采用质量分数2.5%的邻苯二甲酸二壬酯和质量分数2.5%的硅藻土,以chromsorb G·DMCX(150~180μm)为担体的色谱填充柱进行分离,氢火焰离子化检测器进行检测,用峰面积外标法进行定量分析,同时对工业苯酚丙酮装置氧化尾气组成进行气相色谱分析。对色谱柱的选择、操作条件的优化、定性、定量分析,进样量和线性范围、最低检测限等实验项目进行了考察,实验结果表明此方法具有操作简单、分析速度快、分析成本低、重复性与准确性好等特点。     

丙酮诱导不同形状的金纳米粒子整形

在HAuCl4-葡萄糖-丙酮体系中,丙酮不仅能起光敏剂、加速光化学还原Au(III)离子的反应,还能诱导已形成的金纳米粒子整形。整形过程伴随着明显的可见/近红外吸收光谱变化,并形成一些全新的纳米结构。实验结果表明,金纳米粒子的整形方式与初始金纳米粒子的形貌密切相关,对于球形的金纳米粒子,整形后形成纳米线;而对于锥形纳米粒子则形成金纳米片。     

正己烷和乙酸乙酯间歇共沸精馏分离共沸剂的研究

正己烷和乙酸乙酯形成最低共沸物,采用间歇共沸精馏方法分离回收时,共沸剂的选择和用量直接影响实验效果。研究了正己烷-乙酸乙酯共沸物系间歇共沸精馏法分离适宜的共沸剂,并从理论上和实验中考察了共沸剂与原料适宜的配比。实验结果表明,丙酮为合适的共沸剂,当丙酮和正己烷的质量比为1.15时,正己烷和乙酸乙酯的收率最高,分别达75.15%和73.89%。通过实验绘制了正己烷-乙酸乙酯-丙酮三元物系的剩余曲线,确定了正己烷-乙酸乙酯共沸物系分离步骤:共沸精馏塔中馏出丙酮和正己烷的共沸物和高纯度的乙酸乙酯;萃取塔中用水萃取丙酮和正己烷的混合物得到较纯的正己烷;萃取后的丙酮水溶液由共沸剂精馏回收塔回收丙酮。     

乙醇提取-丙酮沉淀法提取分离茶皂素的工艺研究

以油茶饼粕为原料,采用乙醇提取-丙酮沉淀法对茶皂素进行提取分离。以茶皂素纯度和得率为考察指标,对乙醇体积分数、液料比、提取温度、提取时间、提取次数、提取液浓缩程度和丙酮用量等工艺参数进行了单因素优化。结果表明：体积分数95%的乙醇为提取溶剂,乙醇与预处理过的油茶饼粕液料比为9：1（mL：g）,提取温度为70℃,提取时间为4 h,提取次数为2次,提取液浓缩至刚好有固体析出,丙酮用量为4倍浓缩液体积量时提取分离效果较佳,得到的茶皂素纯度为85.17%,得率为9.82%。不同溶剂打浆对产品纯化效果的比较发现：丙酮、乙酸乙酯、无水乙醇、体积分数95%的乙醇作为打浆纯化溶剂用于提高茶皂素纯度效果均不明显。     

微生物燃料电池处理丙酮和氨氮废水及同步产电性能研究

本研究利用阴离子交换膜作为分隔膜构建了生物阴极微生物燃料电池（Microbial fuel cell, MFC），通过硝化反硝化过程去除氨氮、降解丙酮同时产电。实验探究了不同丙酮浓度（50 mg/L、100 mg/L、300 mg/L、500 mg/L、700 mg/L）对MFC产电及氨氮（200 mg/L）的去除效果。结果表明，在选定的丙酮浓度范围内，丙酮的去除率均高达96%以上；当丙酮浓度高于300 mg/L时，氨氮的去除开始受到抑制，氨氮最高去除率为73.7%，且丙酮浓度为300 mg/L时，对应的MFC的产电性能最佳，最高输出功率密度可达49.7 mW/m2。高通量测序技术分析了阳极及阴极微生物群落结构，从门级分类上看，阳极中的优势微生物群落主要为变形菌，拟杆菌门及厚壁菌门；阴极上的优势微生物群落为拟杆菌门、放线菌门、变形菌门及酸杆菌门。从属级分类上看，阳极主要的优势菌种为Comamonas, Acetoanaerobium，Stenotrophomonas。阴极主要的优势菌种为Rhodococcus，Aridibacter, Thauera，Ignavibacterium。     

Electrophysiological and Behavioral Responses of <Emphasis Type="Italic">Ips subelongatus</Emphasis> to Semiochemicals from Its Hosts,Non-hosts,and Conspecifics in China

Volatiles from hosts, non-hosts, interspecifics, and conspecifics of the Asian larch bark beetle, Ips subelongatus Motsch., were analyzed using both gas chromatographic-electroantennographic detection (GC-EAD) and gas chromatography/mass spectrometry (GC-MS) techniques, and field trapping bioassays in Inner Mongolia, China. GC-EAD experiments indicated that I. subelongatus antennae (both sexes) strongly responded not only to the major male-produced conspecific components, ipsenol, and ipsdienol, but also to other bark beetle compounds (cis-verbenol and verbenone), host monoterpenes (α-pinene, β-pinene, and para-cymene) from Larix sp. logs, and non-host leaf (green leaf volatiles and geranyl acetone) and bark (C₈-alcohols and trans-conophthorin) volatiles. Repeatable EAD responses were also found to two compounds from hindgut extracts that are undetectable by GC. One of these minor compounds was identified as amitinol. Field trapping experiments showed that the EAD-active, major male-hindgut component, racemic ipsenol, is the only individual compound that significantly attracted both sexes of I. subelongatus, whereas all other compounds, including previously reported pheromone components of European Ips cembrae, ipsdienol and 3-methyl-3-buten-1-ol, were unattractive. Ipsdienol, 3-methyl-3-buten-1-ol, or their binary blend had no synergistic or antagonistic effects on I. subelongatus attraction when combined with ipsenol, whereas cis-verbenol (a synomone) and verbenone (the antiaggregation semiochemical) inhibited its attraction to the ipsenol-containing attractive blend. A mixture of three EAD-active host monoterpenes, α-pinene, β-pinene, and para-cymene, was unattractive, but interrupted the pheromone response of I. subelongatus. Geranyl acetone, one of the strong EAD-active non-host volatiles also significantly reduced the number of I. subelongatus captured in traps baited with ipsenol-containing attractive blend. Our results add support to the recent phylogenetic finding that European and Asian larch bark beetles should be regarded as two distinct species: I. cembrae infecting larch in Europe and I. subelongatus infesting larch in Asia.