在线脱醚在氧化工艺环己酮装置中的应用

环己酮是生产尼龙、己内酰胺、己二酸、香料、医药、树脂等化工产品的原料,作为溶剂广泛用于涂料、染料、油漆、农药、橡胶、印刷和塑料的回收等方面。按原料不同,工业生产环己酮的方法主要有苯酚加氢法、环己烯水合法以及环己烷氧化法。氧化工艺环己酮装置在环己烷与氧气高温氧化过程中,会生成副产物丁基环己基醚等,该类物质沸点与目标产物环己醇相差不大,因而在后续真空精馏中难以除去,也不参与环己醇脱氢反应,作为惰性物质在系统内循环累积,浓度不断上涨,影响环己酮装置精馏工序的分离效果和脱氢反应过程。某公司环己酮装置在国内首次运行在线脱醚技术,成功将系统内醚含量脱除至1.7%以下,且能在长周期维持系统内低醚含量,降低装置运行能耗,对国内环己酮行业有较强的指导意义。

环己烷氧化生产环己酮工艺中脱醚技术运用与控制

环己酮是重要有机化工原料和溶剂,是制造己内酰胺、己二酸和尼龙的重要中间体。在我国,一半以上环己酮作为生产己内酰胺原料,近两成环己酮作为生产己二酸原料,其余环己酮作为相关化工原料。另外,环己酮还是优良溶剂,可用作油漆硝化纤维、氯乙烯聚合物和共聚物溶剂。随着我国化纤工业迅速发展,己内酰胺、己二酸产量逐年增加,对环己酮需求量也日益剧增,其利用前景广阔。脱醚技术运行与控制对环己烷氧化生产环己酮工艺有着重要意义,用来改变装置长周期运行,减少系统内循环,提高脱氢单元反应转化效率,给企业带来更高经济效益。从安全、节能、经济以及系统操作稳定方面都有长远的意义。

脱醚转晶方法对α-AlH_(3)的影响

三氢化铝(AlH_(3))是一种理想的储氢材料。以氢化铝锂和氯化铝为原料,采用湿法化学法合成了三氢化铝醚合物,并通过3种不同方法对其进行脱醚转晶制备AlH_(3)。通过X射线衍射仪、扫描电镜、同步热分析仪、红外光谱对3种方法制备的AlH_(3)各项性能进行系统研究。研究表明,3种方法制备的产物晶型均以α型为主,产率均高于80%;化学结构相似,热分解性质相当;采用液体甲苯法制备的产物粒径相对较大,约为10μm,但纯度仅为90%。

7-羰基-12-脱氢松香酸甲酯硫醚的合成

以脱氢松香酸为底物,通过甲酯化、溴代、硝化等步骤,合成了标题化合物,其结构经1HNMR、MS和元素分析等确定。

新型吸入麻醉药脱氟醚的研究进展

自Stephen提出理想的吸入麻醉药标准以来,以氟烷为代表的一些药物已接近这一水平,但仍有不尽人意之处。脱氟醚(Desflurane)具有组织溶解度低,麻醉诱导快、苏醒早、对循环功能影响小和在机体内几乎无代谢产物等特点。因此,引起人们的重视。1990年初Jones首先在临床试用,接着英美等国许多学者都相继报道了脱氟醚的应用研究。本文就近年国外资料,对脱氟醚的药理和应用前景等综述如下。

低温选择加氢脱硫醚催化剂的研究

以Al2O3为载体,采用浸渍法制备了多种金属氧化物催化剂,考察了所制备催化剂的低温选择加氢脱硫醚性能。以含1-戊烯和叔丁基甲基硫醚的环己烷模型化合物为原料,考察了单组分、双组分及三组分元素组合对催化剂性能的影响。实验结果表明,Mo系和W系双组分催化剂的选择加氢脱硫醚的性能明显优于单组分催化剂;经过适当组合的三组分催化剂的选择加氢脱硫醚的性能有所改变,其中以NiMoZn/Al2O3催化剂的选择加氢脱硫醚性能最好。以FCC全馏分汽油为原料,对NiMoZn/Al2O3催化剂进行150 h的长周期实验,在氢压1.5 MPa、温度200℃、液态空速4 h-1、氢油体积比100的条件下,异戊二烯完全脱除,叔丁基甲基硫醚转化率维持在80%左右,单烯几乎不加氢饱和,且有一定的单烯异构。

湿法化学法合成三氢化铝研究概述

三氢化铝作为一种储氢材料具有十分优异的性能,例如:储氢密度大、放氢温度低、燃烧后产物绿色无污染等诸多优点,广泛应用于航空航天以及军工领域。综述了采用“湿法”合成时产生的中间体三氢化铝缔合物以及产品α-AlH_(3)的物理以及化学性质对制备过程的影响。α-AlH_(3)的常规“湿法”合成需要分两步合成,第一步缔合物制备,介绍了几种不同醚合物的制备方法;第二步脱溶剂化转晶,脱溶剂化转晶主要分为固相甲苯法、液体甲苯法、真空法,分析了各自存在的优缺点。最后提出了一些可以改进的方向。

甲醇精馏工艺及装置

绍了甲醇精馏工段的工艺和装置,论述了装置系统自调控制情况,并提出了对装置技术改进的措施。通过改进,装置排放残液中的甲醇含量降低到0.05%以下,COD降低到950mg/L以下。

甲醇精馏工艺探讨

首先对醇精馏工段的工艺与装置进行简要介绍,探讨了装置系统自调控制状况,提出了改进装置工艺流程的具体措施。

Hydrodeoxygenation of Anisole over Ni/α-Al2O3 Catalyst

Ni-based catalysts supported on di erent supports （α-Al2O3,γ-Al2O3, SiO2, TiO2, and ZrO2） were prepared by impregnation. Effects of supports on catalytic performance were tested using hydrodeoxygenation reaction （HDO） of anisole as model reaction. Ni/α-Al2O3 was found to be the highest active catalyst for HDO of anisole. Under the optimal conditions, the anisole conversion is 93.25% and the hydrocarbon yield is 90.47%. Catalyst characteriza-tion using H2-TPD method demonstrates that Ni/α-Al2O3 catalyst possesses more amount of active metal Ni than those of other investigated catalysts, which can enhance the cat-alytic activity for hydrogenation. Furthermore, it is found that the Ni/α-Al2O3 catalyst has excellent repeatability, and the carbon deposited on the surface of catalyst is negligible.

Separation of Sulfur/Gasoline Mixture with Polydimethylsiloxane/ Polyetherimide Composite Membranes by Pervaporatlon

Worldwide environment has resulted in a limit on the sulfur content of gasoline.It is urgent to investigate the desulfurization of gasoline.The polydimethylsiloxane(PDMS)/polyetherimide(PEI)composite membranes were prepared by casting a PDMS solution onto porous PEI substrates and characterized by scanning electron microscope(SEM).The membranes were used for sulfur removal from gasoline by pervaporation.The effects of feed temperature,sulfur content in the feed and PDMS layer thickness on membrane performance were investigated,and an activation energy of permeation was obtained.Experimental results indicated that higher feed temperature yielded higher total flux and lower sulfur enrichment factor.The total flux varied little with the increase of sulfur content in the feed,but the sulfur enrichment factor first increased with the amount of thiophene added into the gasoline,and then the variation was little.The increase of PDMS layer thickness resulted in a smaller flux but a larger sulfur enrichment factor.The result indicates that the PDMS/PEI composite membranes are promising for desulfurization by pervaporation.

Study on the influence of crown ether on arsenic behavior during coal pyrolysis

The influence of crown ether on behaviors of arsenic at different temperatures and residence time was investigated during the pyrolysis of Tuanbo （TB） coal. The modes of occurrence of arsenic were determined by sequential chemical extraction, density fractionation and demineralization. The results indicated that at the same temperature and residence time, the arsenic removal adding dibenzo-18-crown-6 was higher than that adding 18-crown-6, and were all higher than that of TB coal during pyrolysis. When temperature was 850 ℃ and residence time was 30 min, the arsenic removal of TB coal was 30.63%; at the same condition, the arsenic removal while adding 18-crown-6 was 33.21%, higher than that of TB coal; and the arsenic removal while adding dibenzo-18-crown-6 was 67.41%, significantly higher than that of TB coal. From the results, we can see that adding crown ether can improve the arsenic removal during coal pyrolysis, and especially be conducive to the arsenic which is mainly associated with sulfates ＆ monosulfides and that in stable forms.

麻醉学

9731858 妊娠时非产科手术麻醉病例的探讨[日]/福田志朗∥麻醉.-1995,44(7).-1048 冀医情 9731859 麻醉下猪行剖腹术后可同时诱发出肝热休克和急性期基因表达/Benedikt H J∥Anesthesiology.-1995,83(4).-850～859

Hydrodeoxygenation of anisole over different Rh surfaces

The cleavage of the alkoxy(Ar-O-R) ether bond present in anisole is an interesting hydrodeoxygenation(HDO) reaction, since this asymmetric group contains two different C–O bonds, Caryl–O or Calkyl–O, which could potentially cleave. Recent work on the HDO of anisole over Pt, Ru, and Fe catalysts has shown that a common phenoxy surface intermediate is formed on all three metals. The subsequent reaction path of this intermediate varies from metal to metal, depending on the metal oxophilicity. Over the less oxophilic Pt, phenol is the only primary product. By contrast, on the more oxophilic Fe catalyst, the sole primary product is benzene instead of phenol. On Ru, with intermediate oxophilicity, both benzene and phenol are primary products. In this contribution, we have investigated Rh catalysts of varying surface nanostructures. A combination of experimental measurements and computational calculations was used to explore the effects of varying metal coordination number, an additional parameter that can be used to control the oxophilicity of a metal. The results confirm that metal oxophilicity is a good descriptor for HDO performance of metal catalysts and it can be controlled via selection of metal type and/or metal extent of coordination. Small Rh metal clusters with low coordination metal sites are more active for the deoxygenation pathway but also quickly deactivated while large clusters with high coordination sites are more active toward hydrogenation and more stable.

Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water

The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

Effects of indium on Ni/SiO_2 catalytic performance in hydrodeoxygenation of anisole as model bio-oil compound: Suppression of benzene ring hydrogenation and C–C bond hydrogenolysis

SiO2‐supported monometallic Ni and bimetallic Ni‐In catalysts were prepared and used for hydrodeoxygenation of anisole,which was used as a model bio‐oil compound,for BTX(benzene,toluene,and xylene)production.The effects of the Ni/In ratio and Ni content on the structures and performances of the catalysts were investigated.The results show that In atoms were incorporated into the Ni metal lattice.Although the Ni‐In bimetallic crystallites were similar in size to those of monometallic Ni at the same Ni content,H2uptake by the bimetallic Ni‐In catalyst was much lower than that by monometallic Ni because of dilution of Ni atoms by In atoms.Charge transfer from In to Ni was observed for the bimetallic Ni‐In catalysts.All the results indicate intimate contact between Ni and In atoms,and the In atoms geometrically and electronically modified the Ni atoms.In the hydrodeoxygenation of anisole,although the activities of the Ni‐In bimetallic catalysts in the conversion of anisole were lower than that of the monometallic Ni catalyst,they gave higher selectivities for BTX and cyclohexane as a result of suppression of benzene ring hydrogenation and C–C bond hydrogenolysis.They also showed lower methanation activity.These results will be useful for enhancing carbon yields and reducing H2consumption.In addition,the lower the Ni/In ratio was,the greater was the effect of In on the catalytic performance.The selectivity for BTX was primarily determined by the Ni/In ratio and was little affected by the Ni content.We suggest that the performance of the Ni‐In bimetallic catalyst can be ascribed to the geometric and electronic effects of In.

Iron-mediated cross dehydrogenative coupling(CDC) of terminal alkynes with benzylic ethers and alkanes

Iron-mediated sp-sp3 C-C bond formation through the cross dehydrogenative coupling(CDC) of terminal alkynes with benzylic ethers or alkanes has been developed.The inexpensive iron salt is used as the catalyst to make this transformation environmentally benign.Iron-mediated sp-sp3 C-C bond formation through the cross dehydrogenative coupling(CDC) of terminal alkynes with benzylic ethers or alkanes has been developed.The inexpensive iron salt is used as the catalyst to make this transformation environmentally benign.

Photocatalytic debromination of decabromodiphenyl ether by graphitic carbon nitride

The graphitic carbon nitride(g-C3N4) is found to be an efficient photocatalyst for the reductive degradation of decabromodiphenyl ether(BDE209) under UV irradiation(>360 nm).g-C3N4 was prepared by heating dicyandiamide.X-ray diffraction,X-ray photoelectron spectroscopy,and UV-vis spectra were used to characterize the properties of as-prepared catalysts.The photoreductive degradation kinetics of BDE209 was further investigated under different reaction conditions.The degradation of BDE209 is a stepwise process,and the bromines at meta positions are much more susceptible to remove than those at the ortho and para positions.A possible photoreductive mechanism was also proposed.

Analysis of hydroxylated polybrominated diphenyl ethers in plant samples using ultra performance liquid chromatography-mass spectrometry

A method was developed for the analysis of hydroxylated brominated diphenyl ethers (OH-PBDEs) in plant samples using an ultra performance liquid chromatography-triple quadrupole mass spectrometer (UPLC-ESI-MS/MS) in negative mode. Plant samples were extracted and cleaned up through florisil column, resolved on a 100 mm C18 column with linear gradient elution and detected by mass spectrometry in multiple reaction monitoring (MRM) mode. The method provided good recoveries rang- ing from 68.2% to 94.6%, relative standard deviation (RSD) in the range of 3.2% - 9.1%, and limits of quantification (LOQ) defined as the signal-to-noise ratio of 10 of 0.3-2.1 ng/g. It allowed a fast separation and sensitive quantification of the isomers and homologues of seven OH-PBDE congeners 2′-OH-BDE-3, 3′-OH-BDE-7, 4′-OH-BDE-17, 3′-OH-BDE-28, 3-OH-BDE-47, 5-OH-BDE-47 and 6-OH-BDE-47. The method was successfully applied to identify and quantify the formation of hydroxylat- ed metabolites in alfalfa exposed to BDE-209. Five OH-PBDEs were detected in plant tissues, and more congeners were found in roots than in shoots. To our knowledge, this work represents the first attempt to validate UPLC-MS/MS method to quantify OH-PBDEs in plant samples without derivatization.