一种自热式低浓度乙烯与苯烃化生产乙基苯的方法

一种自热式低浓度乙烯与苯烃化生产乙基苯的工艺，苯和低浓度乙烯原料气的反应温度接近操作条件下苯的沸腾温度，在有液相苯存在的反应段利用液态苯汽化所需汽化热来吸收乙烯和苯反应放出的热量，反应段上下的流出物分别用来加热原料苯和原料气，从而达到反应器的热量合理利用和使反应可能在不需外加热的条件下连续运行，具有热能利用高，反应器结构简单，能耗低，投资省，反应效率高和产品中杂质少等优点。     

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该发明涉及一种乙烯液相烷基化制乙苯的方法，主要解决以往技术中存在苯和乙烯液相烷基化反应中，催化剂稳定性和再生性能差的问题。该发明通过采用以乙烯和苯为原料，以p沸石分子筛为催化剂，催化剂在使用前先用高温水蒸汽处理，然后再用有机酸处理，反应温度为200—270℃，反应压力为3．0—4．0MPa，苯／乙烯摩尔比为3-10条件下，乙烯发生液相烷基化反应生成乙苯的技术方案较好地解决了该问题，可用于液相烷基化制乙苯的工业生产中。     

苯与烯烃烷基化反应的研究进展

详细介绍了苯与乙烯，苯与丙烯，苯与直链烯烃烷基化反应的研究现状，指出催经反应精馏技术最具应用前景，但是塔内流体力学及传质行为的研究还显薄弱。     

响应面法分析优化苯与乙烯的烷基化反应

对改性β-分子筛催化的苯与乙烯的烷基化反应的工艺条件进行了优化。通过单因素实验确定了反应温度、空速、乙烯与苯的摩尔比的取值范围,并用响应面法(Box-Behnken设计法)确定最佳工艺参数为:反应温度154℃,空速2h-1,乙烯与苯的摩尔比1∶3。在此条件下,苯的转化率达到56.274%、乙苯的选择性达到86.592%。     

国外动态

由苯和乙烯直接合成苯乙烯日本理化学研究所开发了由苯和乙烯为原料一步反应直接合成苯乙烯的新的反应过程。它是采用铑金属粒做催化剂,在少量一氧化碳的存在下,通入苯和乙烯在200℃下,加热加压反应,得到苯乙烯和二乙基酮。此过程与过去的苯乙烯制造工程相比,有流程     

催化裂化干气中乙烯制乙苯绝热反应温升和去热方式

本文介绍催化裂化干气中乙烯与苯制乙苯过程反应热平衡,讨论了进料乙烯浓度和苯/乙烯比与反应温升的关系,并论述了烃化反应器分层注入催化干气或苯的取热方式。结果表明,能有效地降低温升,确保催化剂处于最佳温区操作。     

Beta分子筛改性对催化苯和乙烯烷基化反应的影响

苯和乙烯烷基化反应是重要的乙苯生产途径,Beta分子筛是该过程的重要催化剂。苯和乙烯烷基化反应是一个酸中心催化过程,因此Beta分子筛的表面酸性与催化反应性能之间有密切联系。对工业Beta分子筛进行浸Mg、高温水蒸汽处理和高温焙烧等改性处理,考察改性方法对Beta分子筛酸性及催化苯和乙烯烷基化性能的影响,结果表明,浸Mg改性能增加分子筛总酸量,但酸强度降低,导致催化活性降低,苯和乙烯烷基化反应主要发生在分子筛强酸中心;高温水蒸汽处理后,分子筛酸强度分布基本不变,但总酸量降低,导致乙烯转化率降低;高温焙烧处理导致分子筛结晶度下降,催化活性下降。     

苯与乙醇烷基化制乙苯的研究

1 前言乙苯生产主要采用苯和乙烯在催化剂上进行烷基化反应而制得的。近年来,人们又对在ZSM-5分子筛上进行苯与乙醇直接烷基化制乙苯发生了浓厚的兴趣。对于我国内地短缺乙烯地区发展苯乙烯型的系列产品,用来源丰富、运输和储备方便的乙醇代替乙烯具有适合国情的现实意义。从长远观点看,乙醇可从煤或天然气中大量制取。2 实验装置与流程苯与乙醇烷基化反应的实验采用φ12 mm×800 mm 不锈钢的等温积分反应器,反应管     

第七届国际表面活性剂会议论文摘要(续)

25、磷酸被某些脂肪酸进行酯化的研究磷酸同己醇、十四醇和十八醇以对位甲苯磷酸为催化剂。在不活泼溶剂中在391～418°K温度下进行酯化，研究了反应的化学动力学。磷酸同脂肪族醇进行酯化属于磷酸的二级反应。26、关于环氧丙烷同乙烯二胺的反应以1～4克分子环氧丙烷同乙烯二胺进行加合反应，研究其反应动力学，并叙述N、N、N'、N'—四（2-羟丙基）乙烯二胺的氧丙烯化作用对于产品的组成及M值的影响。环氧丙烷（PO）同乙烯二胺（EDA）的反应基本上分为两步。第一步，可在不需催化剂的情况下进行，由于连续不断的加合反应而生成四克分子的PON、N、N'、N'—四（2羟丙基）乙烯二胺。第二步，有碱性催化剂，FO进一步与生成的羟氧基进行加合反应，除N、N、     

AF—5分子筛催化剂上苯气相乙基化反应的失活动力学研究…

在绝热固定床实验反应器中对苯和乙烯在ＡＦ－５分子筛催化剂上进行的烷基化反应的失活动力学作了研究。初步考察表明乙烯和苯都会引起失活，但乙烯引起的失活是主要的。在和工业反应器类似的操作条件下系统测定了由催化剂失活引起的乙烯转化率随操作时间的变化，所得数据将用于建立失活动力学模型。     

环保型粗苯萃取精制新工艺的设计开发

开发的粗苯萃取精馏法是一种环保型精制新工艺,开创了国内第三条苯精制的工艺技术路线,该装置为国内首套规模最大的苯萃取精制装置。不仅可以得到合格的三苯产品,而且得到昂贵的化工原料一纯度≥99％的噻吩。     

菲氧化制菲醌的方法及研究进展

菲醌是一种重要的化工原料。综述了国内外相关文献、专利中菲氧化合成菲醌的各种研究方法及特点,简要阐述了一些收率高或者理念新的方法,以期对有关科研人员有所借鉴。     

Influence of chlorine substituents on biological activity of chemicals

A number of well known polychlorinated chemicals are toxicologically and environmentally unsafe. Because of their persistence they are in the focus of public discussions against chlorine chemistry. However, chlorinated organic chemicals in the molecular weight range between 200 and 600 constitute an important and indispensable segment in the arsenal of existing biologically active chemicals used as pharmaceuticals or crop protection agents. Over the course of time it has been found empirically that the introduction of a chlorine atom into one or more specific positions of a biologically active molecule may substantially improve the intrinsic biological activity. In some cases the presence of a chlorine atom is even crucial for significant activity of a compound derived from nature or chemical synthesis like in the diverse compounds 1 to 12 and 23 to 30 . But in other cases chlorination diminishes or abolishes biological activity as shown for the chlordane homologues 139 to 143 . Thus a chlorine atom, like any other substituent, is a modulator of activity as represented in the many examples 31 to 124 . Almost all non-reactive chlorinated chemicals and chlorine-free chemicals are devoid of any biological activity at the highest concentration typically used in primary screening tests for discovery of useful biological properties. The influence of a substituent such as chlorine on the biological activity of a potential drug or crop protection agent still has to be established empirically in biological experiments designed to detect desired activity or toxicological properties. Sometimes chlorine does prove to be the optimum for improvement of activity. Long-term rigorous investigations of several hundred chlorinated compounds, registered by the authorities as pharmaceutical drugs or crop protection agents, show that the generalisation (“all chlorinated chemicals as a rule are dangerous”), deduced from the negative toxicological properties of a hundred chlorinated and reactive compounds of low molecular weight that are relevant in terms of safe working conditions in the chemical industry and for ecological safety, is not justified. Chlorinated compounds are not generally toxic or dangerous. Highly reactive chemicals or polychlorinated compounds can not be compared with regard to toxicological properties with unreactive compounds having a low degree of chlorination. The chlorine atom, as one of many possible substituents used in synthetic organic chemistry, will remain in the future one of the important tools for probing structure–activity relationships in life science research and as a molecular component in commercialised compounds, in order to provide safer, more selective and more environmentally compatible products with higher activity for medicine and agriculture.     

聚合物微凝胶的制备及其在不饱和聚酯改性中的应用

以苯乙烯和丙烯酸丁酯为单体，二乙烯基苯（ＤＶＢ）为交联剂利用乳液聚合法制备出聚合物微凝胶并研究了ＤＶＢ及乳化剂用量对聚合反应的影响，将所得到的微凝胶用于增进不饱和聚酯（ＵＰ）的流变性。试验证明聚合物微凝胶对提高ＵＰ的触变指数具有良好的效果。     

Bitumen paints,an old story with new approach,part-1, solvent based paints

Bitumen paints have lost their importance with the advent of modern polymers during the last century, but they are still used for large area applications such as tanks and pipelines. The main application of bitumen is as road paving binder and most of the research is devoted to improving properties by physical or chemical modification by polymers. Applying this approach to paints has shown that improvement in properties such as hardness and drying times without loss in adhesion and flexibility can be obtained by physical as well as physical followed by chemical modifications with EVA, reactive terpolymers and isocyanate prepolymers. Correct formulation with fortifying additives of asphaltene powder or hydrocarbon resin was another contributing factor.     

Chemically engineered extracts: source of bioactive compounds

Biological research and drug discovery critically depend on access to libraries of small molecules that have an affinity for biomacromolecules. By virtue of their sustained success as sources of lead compounds, natural products are recognized as "privileged" starting points in structural space for library development. Compared with synthetic compounds, natural products have distinguishing structural properties; indeed, researchers have begun to quantify and catalog the differences between the two classes of molecules. Measurable differences in the number of chiral centers, the degree of saturation, the presence of aromatic rings, and the number of the various heteroatoms are among the chief distinctions between natural and synthetic compounds. Natural products also include a significant proportion of recurring molecular scaffolds that are not present in currently marketed drugs: the bioactivity of these natural substructures has been refined over the long process of evolution. In this Account, we present our research aimed at preparing libraries of semisynthetic compounds, or chemically engineered extracts (CEEs), through chemical diversification of natural products mixtures. The approach relies on the power of numbers, that is, in the chemical alteration of a sizable fraction of the starting complex mixture. Major changes in composition can be achieved through the chemical transformation of reactive molecular fragments that are found in most natural products. If such fragments are common enough, their transformation represents an entry point for chemically altering a high proportion of the components of crude natural extracts. We have searched for common reactive fragments in the Dictionary of Natural Products (CRC Press) and identified several functional groups that are expected to be present in a large fraction of the components of an average natural crude extract. To date, we have used reactions that incorporate (i) nitrogen atoms through carbonyl groups, (ii) sulfur by transformation of -OH and amines, and (iii) bromine through double bonds and aromatic rings. The resulting CEEs had different composition and biomolecular properties than their natural progenitors. We isolated a semisynthetic β-glucosidase inhibitor from a CEE prepared by reaction with benzenesulfonyl chloride, an antifungal pyrazole from a CEE prepared by reaction with hydrazine, and an acetylcholinesterase inhibitor from a CEE prepared through bromination. Our results illustrate how biological activity can be generated through chemical diversification of natural product mixtures. Moreover, the level of control that can be asserted in the process by judicious design and experimental choices underscores the potential for further development of CEEs in both basic research and drug discovery.     

不同烷氧基钬掺杂增韧聚苯乙烯的研究

采用四种烷氧基钬化合物掺杂和苯乙烯本体聚合制备了不同掺钬聚苯乙烯材料，XPS测试表明掺杂聚苯乙烯中存在着钬离子和聚苯乙烯大分子苯环π电子之间存在配位作用。SEM照片和DMTA的数据探讨烷氧基钬增韧聚苯乙烯的作用机理，并讨论不同链长的烷氧基对聚苯乙炮的增韧作用影响，表明掺钬聚苯乙烯的冲击强度显著提高，表明烷氧基钬对聚苯乙烯有明显的增韧改性作用。     

X-ray Photoelectron Spectroscopy Analysis of Potassium Adsorption onto v-SiO2: Observation of Reactive Surface Defect Sites

The adsorption of potassium onto a clean silica surface has been studied by X-ray photoelectron spectroscopy (XPS). The fracture surface of silica was cleaned by Ar⁺ sputtering and exposed to potassium metal vapor for 10-s intervals up to 50 s, resulting in 0.2 to 2 monolayer coverage. High-resolution XPS spectra were recorded for the K 2p, O 1s, and Si 2p photoelectrons at each potassium exposure. Potassium uptake curves were generated from peak areas which suggest the mechanism of adsorption. Curve synthesis techniques were employed on the O 1s spectra to identify the various chemical states present. A decrease in a reactive state is observed as the number of nonbridging oxygen states increases. Angleresolved XPS was also used to determine the relative position, with respect to depth, of these reactive sites, showing that they are at a higher concentration near the surface.     

Modelling phenanthrene biodegradation and mineralisation in polluted soil using toluene as gaseous cosubstrate

BACKGROUND: Mathematical models describing the physical, chemical and biological processes that take place in bioremediation are necessary to design and optimise these technologies. This work models the effect of toluene as a gaseous cosubstrate in the degradation of phenanthrene in soil, considering the consumption of pollutants, the production of intermediate degradation compounds and mineralisation. The proposed model consists of a set of sequential reactions to convert phenanthrene to carbon dioxide and biomass with the production and consumption of phthalic acid, which is the main intermediate metabolite. RESULTS: The considerations of the model were supported by experimental data, and it was evaluated for phenanthrene degradation kinetics with previously reported packed column reactor experiments. The mathematical model proposed describes the mineralisation of phenanthrene accurately and also predicts a reduced accumulation of phthalic acid when toluene is added as cosubstrate. The model fits the experimental data of phenanthrene degradation when toluene is added but slightly overestimates the residual phenanthrene in the control case. CONCLUSION: The simplified model of sequential reactions represents the column experiments (P < 0.05) for phenanthrene degradation and mineralisation with toluene as cosubstrate, considerating the production and consumption of phthalic acid. Copyright © 2008 Society of Chemical Industry     

Shock-induced carbonization of phenanthrene at pressures of 7.9-32 GPa

The chemical behavior of phenanthrene during a reaction triggered by shock waves, and its influence on the physical property of phenanthrene were studied over the pressure range of 7.9-32.0 GPa. Chemical analyses showed that shocked phenanthrene included insoluble carbonaceous material containing amorphous carbon, polycyclic aromatic hydrocarbons (PAHs) with molecular weights ranging from 128 to 356, and unreacted phenanthrene. No diamond and fullerenes were detected in the shocked phenanthrene. The results indicate that reactions triggered by shock wave are dehydrogenation, which causes carbonization and radical addition reactions, and ring cross-linking. Carbonization is the most dominant and rapidly proceeded above 20.0 GPa. Thus, an abrupt increase of compressibility of phenanthrene above 20.1 GPa previously reported is caused by the drastic carbonization.