超酸硝化法合成六硝基六氮杂异伍兹烷

分别采用硝酸-硝酸钾、发烟硫酸-硝酸钾、发烟硫酸-硝酸钠和发烟硫酸-硝酸铵4种超酸体系对六乙酰基六氮杂异伍兹烷(HAIW)进行硝化，合成了六硝基六氮杂异伍兹烷(HNIW)，属首次用超酸硝化方法合成HNIW。通过实验得到最佳硝化反应条件，以发烟硫酸一硝酸钾超酸体系为硝化剂，当温度为70℃，反应时间为3．5h，目标产物的最高得率为83．1％，质量分数达到98％以上(达到应用的纯度)。同时对超酸硝化N双取代的酰胺类化合物HAIW的反应机理进行了探讨，超酸体系中含有高浓度的硝酰正离子(NO2^ )，在该反应中NO2^ 是进攻酰胺氮原子的有效基团。     

固载杂多酸PW12／SiO2催化合成对苯二甲酸二异辛酯

固载杂多酸ＰＷ１２／ＳｉＯ２对苯二甲酸与异辛醇的酯化反应具有较高的催化活性，实验结果表明：在催化剂用量占对苯二甲酸重量４．０％，反应温度２１０－２３０℃，醇酸比为４．０：１的条件下，反应７．０ｈ，对苯二甲酸的转化率达到９９％以上。固载杂多酸催化剂在应用中易于分离，回收率高，在产品中的残留低，产品对苯二甲酸二辛酯的酸值低、稳定性好，颜色较浅，克服了硫酸催化剂和钛酸丁酯催化剂的缺点，产品质量明显优于硫     

DOTP酯化反应规律的研究

探索了对苯二甲酸和异辛醉在钛酸四丁酯催化下制备对苯二甲酸二异辛酯（ＤＯＴＰ）的反应规律，在醇、酸摩尔比为２．７～３．０：１，催化剂用量为０．５～０．７（ｗｔ％）时，ＤＯＴＰ的产率大于９９．５％。     

甲苯的NO／O2硝化新工艺

采用间歇式高压反应器研究了甲苯的NO2／O2硝化反应，考察了反应条件对反应活性的影响。结果表明，适当的催化剂比表面和酸中心对此硝化反应是必要的。在HZSM-5分子筛为催化剂的情况下，NO／甲苯配料比为2：1(摩尔比)，O2压力0．5MPa，控制反应温度为45％，反应时间3h，反应的转化率达到100％，对硝基甲苯的选择性为45％，较混酸法高。     

十二烷基苯磺酸对增塑剂DOTP合成的催化作用

探索了对苯二甲酸和异辛醇在十二烷基苯磺酸催化作用下制备对苯二甲酸二异辛酯（ＤＯＴＰ）的反应规律，在醇、酸摩尔比为３０～４０∶１、催化剂用量为１３１．８（ｗｔ％）时，ＤＯＴＰ的产率达到９９６％。     

HZSM-5催化下N2O5对甲苯的绿色硝化

为解决浓硝硫混酸硝化对硝基甲苯过程中因甲苯的非选择性硝化产生的大量废物和o-MNT对环境的危害,研究了在HZSM-5分子筛催化下,五氧化二氮对甲苯的硝化反应。该方法用N2O5代替浓硫酸,提高了原子经济性,对环境友好。HZSM-5优异的择形性使对硝基甲苯在硝化产物中的比例大幅度提高。考察了反应温度、反应时间,催化剂用量及Si／Al等因素对硝化反应的影响,表明在最佳反应条件下,甲苯硝化反应得率达到42％,对位选择性为78．9％。     

氨基对苯二甲酸的合成

本文以对苯二甲酸为原料经硝化、还原制备了２－氨基对苯二甲酸，并对其结构进行了鉴定。     

3-硝基吡唑的合成

以吡唑为原料，经硝化、转位两步反应合成了3-硝基吡唑、吡唑在硝酸-硫酸介质中硝化，反应温度不超过15℃，反应3．5小时得到N-硝基吡唑，收率为86．6％，再将N-硝基吡唑溶于正辛醇中在185℃-190℃加热回流，得到转位产物3-硝基吡唑，收率为87．8％。硝化反应的创新处是用硫酸代替醋酸和醋酐，作为溶剂的正辛醇可不经处理循环使用。     

对苯二甲酸二辛酯合成反应规律的研究

由对苯二甲酸和辛醇在钛酸四丁酯催化下合成了对苯二甲酸二辛酯(DOTP)。实验探索了搅拌转速、对苯二甲酸粒度、催化剂用量、醇酸物质的量比对反应的影响规律。当醇酸物质的量比大于2.7,催化剂质量分数为0.3％～0.5％时,DOTP的收率大于99.5％。     

氨基对苯二甲酸的合成

本文以对苯二甲酸为原料经硝化，还原制备了２－氨基对苯二甲酸，并对其结构进行了鉴定。     

Deactivation of copper-ion-exchanged hydrogen-mordenite-type zeolite catalyst by SO2 for no reduction by NH3

Deactivation of copper-ion-exchanged hydrogen-mordenite-type zeolite catalyst by SO₂ for NO reduction by NH₃ was examined in a fixed-bed flow reactor. The deactivation of the catalyst was strongly dependent on reaction temperature. At high reaction temperatures over 300°C, the catalyst did not lose its initial activity up to 50 h of operation, regardless of SO₂ feed concentration from 500 to 20,000 ppm. However, at low reaction temperatures near 250°C, apparent deactivation did occur. Changes in the physicochemical properties such as surface area and sulfur content of deactivated catalyst well correlated with catalyst activity, depending upon reaction temperatures. The deactivation was due to pore blocking and/or filling by deactivating agents, which plugged and/or filled the pores of catalyst. The deactivating agents deposited on the catalyst surface were presumed to be (NH₄)₂SO₄ and/or (NH₄)HSO₄ from the results of TGA and ion-chromatography measurement.     

Study on an Aldol Reaction Catalyzed by Ti(IV)/Calix[n]arene Complexes

Ti(IV)/calixarene complexes, formed in situ or previously prepared with standard procedures, can be conveniently used as efficient catalysts in the aldol reaction of Chan's silyloxydiene with a range of aldehydes bearing either activating or deactivating groups, including aromatic, heteroaromatic and α,β‐unsaturated ones. The structure of both calixarene ligand and aldehyde, as well as the reaction conditions, strongly influence the efficiency of the reaction. NMR experiments in conjunction with the experimental results suggest that the structure of the catalytic species in the Ti(IV)/calixarene system prepared in situ is strongly dependent on the concentration and temperature adopted.     

Syntheses of regular copolyamides using triphenyl phosphite and pyridine

In this article, a method of preparing of regular copolyamide (co‐PA) in a reactor using triphenyl phosphite/pyridine as the activating agent was investigated. In two‐step reactions of copolymers prepared from two kinds of dicarboxylic acids and one kind of diamine, oligomer PAs containing amine end groups were first synthesized; then, the second dicarboxylic acid was added to the same reactor to polymerize high molecular weight and regular co‐PAs. However, when oligomers having carboxylic acid end groups were first prepared and another kind of diamine was added, the degree of polymerization was low. The reason proposed was that if the oligomer has an amine end group, it would coexist with the activating agent without deactivating; if the end group was the carboxylic acid end group, deactivation would occur. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 116–122, 2000     

A theoretical analysis of the deactivation of an immobilised enzyme in multi-enzyme reactions in fixed-bed and fluid-bed reactors

The effect of time-averaging on the selectivity to an intermediate R (yR ) and the yield to product S (yR ) in a consecutive reaction A→R→S, occurring in a deactivating fixed-bed reactor, has been examined. Time-averaging smooths the selectivity and increases the yield for high values of the deactivation (λ) and reaction (δ) parameters. The kinetics and dynamics of yR and yS in a deactivating steady-state fluid-bed reactor were also examined. Both non-selective and selective deactivation are considered. The practical implications of the development are considered in terms of an example, in which the values chosen for parameters are arbitrary though reasonable with respect to experimental values.     

Optimal temperature policies for catalytic transport reactors under periodic operation

The influence of inlet gas concentration cycling on the optimal temperature policy of catalytic transport reactors is studied theoretically. The model considered is based on plug flow of gas and catalyst particles with negligible interand intra-particle diffusional resistances and concentration dependent deactivation kinetics. To utilise the concentration of the reactant and the activity of the deactivating catalyst fully a proper temperature sequence along the reactor is needed. Thus, a general optimal temperature policy using the continuous minimum principle is derived for the reactor under periodic operation. The model equations are solved analytically for gas concentration, activity and temperature profiles. Resonance behaviour (maximum in conversion with pulse width) is obtained using the optimal temperature policy for certain sets of parameters. The effects of activation energy groups, reaction and deactivation constant groups and inlet temperature on the optimal temperature policy under periodic operation are evaluated. In all cases an improvement in conversion with the optimal temperature policy under periodic operation over that with an isothermal policy under periodic operation is obtained. A suboptimal policy, comprising constant temperature over different reactor sections, which is useful for implementation purposes is also discussed.     

Pervaporation separation of aqueous mixtures using crosslinked poly(vinyl alcohol), I. Characterization of the reaction between PVA and amic acid

For the purposes of new membrane material development for pervaporation separation based on crosslinked polyvinyl alcohol (PVA), IR spectroscopy and DSC were used to characterize the crosslinking reaction and the imidization of the (PVA)-amic acid system. The IR spectra and the thermal analysis were performed on specimens that had been reacted for several different times at 150°C. The crosslinking reaction between the hydroxy groups of PVA and the carboxylic groups of amic acid was faster than the imidization of the amic acid. The best reaction times were about 30 min for the crosslinking reaction and 90 min for the imidization. The effects of the reaction time and the amic acid content on the thermal and mechanical properties have also been investigated.     

Modeling of heterogeneous reaction kinetics: A stochastic approach

A stochastic model representing the state of the catalyst surface is developed for several possible reaction mechanisms. With the pseudo-steady state assumption, the fresh catalyst solution was used for the initial value of deactivating system The deactivation functions obtained from the present study shows a good agreement with the model proposed by Nam and Froment[1]. When the reaction requires more than one site, the reaction becomes structure sensitive. However, for a single site reaction requiring one site only, the reaction belongs to the class of structure-insensitive reaction Deactivation reactions can also be classified by this manner.     

苯甲醛的缩醛反应研究

对苯甲醛与原甲酸三甲酯的缩醛反应进行了研究,提出了该反应可能的反应机理,考察了不同种类的催化剂、催化剂用量以及原料配比对苯甲醛缩醛反应的影响。通过实验得到了最佳的缩醛化反应条件为:以对甲苯磺酸为催化剂,催化剂用量为反应底物总质量的6‰,n(苯甲醛):n(原甲酸三甲酯)=1:1.5,在室温下反应45min,在此条件下转化率可达99.2%。此外,还对带有不同取代基的苯甲醛与原甲酸三甲酯的缩醛化反应进行了研究,探讨了不同取代基对苯甲醛缩醛反应的影响,结果表明在芳环上对位引入吸电子基团有利于缩醛反应的进行而推电子基团则不利于反应。     

Optimal temperature of fixed-bed reactor for high temperature removal of hydrogen sulfide

To find optimal temperature of the reaction between H₂S gas and ZnO-5 at% Fe₂O₃ sorbent, the effluent gas from a fixed-bed reactor was analyzed by gas chromatography. The experimental results showed that H₂S removal efficiency of sorbent was maximum at 650°C and EDX data were in accordance with this feature. XRD analysis exhibited intriguing phenomenon in that different mechanisms were observed at different temperatures. Chemisorption and chemical reaction was considered to be the main mechanism of H₂S removal at 600 C and 650°C, respectively. SEM photographs supported this interesting phenomenon, but unfortunately TGA and DTA results could not distinguish it. To investigate the effect of sorbent deactivation on the reaction rate, deactivating factor was considered.