1-丁烯齐聚反应:Ⅶ.乙酸镍/氯化乙基铝催化的α烯烃齐聚反应

研究了乙酸镍/有机氯化铝催化α-烯烃(1-C_n~z,n=3,4,6,7,8,10)的齐聚反应。1-C_B~z齐聚转化率、烯烃双键位置移动(简称异构反应)、转化率和二聚物线性率等随n的增加而减小;二聚选择性随n增加而增加。在1-C_n~=齐聚物中有C_(n+2)~=烯烃存在,加氢后则生成烷烃C_(n+2)~0的两种异构体,支链的i-C_(n+2)~0和正构的n-C_(n+2)~0。i-C_(n+2)~0/n-C_(n+2)~0也随着n增加而增大。C_(n+2)~=的存在支持了金属氢化物催化烯烃齐聚反应的机理。     

Ni-B/SiO2非晶态催化剂对苯乙酮的催化加氢研究

用化学还原法制备Ni-B／siO2非晶态催化剂，用XRD、SEM等对其非晶态特征进行表征，并用于苯乙酮的催化加氢实验，讨论了加氢反应条件对苯乙酮的转化率及选择性的影响．结果表明，Ni-B／SiO2非晶态催化剂具有很高的催化活性，在80℃、氢气压力3．0MPa、反应时间5h条件下，苯乙酮的转化率为100％，其中α-苯乙醇选择性为92．1％，乙苯为4．9％，其余(环己基甲基酮和α-环己基乙醇)为3．0％；在120℃、氢气压力3．0MPa、反应时间5h的条件下，苯乙酮的转化率为100％，其中乙苯选择性为90．2％，其余(α-苯乙醇、环己基甲基酮和α-环己基乙醇)为9．8％．因此，温度改变对产物分布有极大的影响．     

低含量高活性负载镍催化剂的制备及其加氢反应研究

以羰基镍为源, 制备了一系列高活性低含量负载镍催化剂. 采用BET、 XRD、 AAS和SEM等对催化剂进行表征. 以苯乙烯选择性加氢为探针反应, 考察了催化剂制备方法、镍含量、溶剂和反应温度、压力、时间对反应结果的影响. 结果表明, 用羰基镍制备的含镍为1%～5%的催化剂对苯乙烯的选择性加氢生成乙苯有很高的反应活性, 苯乙烯转化率和乙苯选择性分别达到了98%和99%以上.     

绿色氧化合成苯乙酮的研究

研究了以氧气为氧化剂、液相氧化乙苯合成苯乙酮反应的各种影响因素,在优化的反应条件(冰乙酸20mL、乙苯5mL、醋酸钴用量为乙苯的4.2%(物质的量)、Br/Co=2.5(物质的量)、氧气流速为100mL/min、常压、温度80℃和反应时间4h)下,乙苯转化率达到99.94%,苯乙酮收率达到98.49%.     

NHPI, CoSPc和TBAB催化的乙苯液-液非均相绿色氧化反应研究

以水为催化剂溶剂与原料乙苯组成液-液非均相体系,以NHPI结合CoSPc组成催化体系,在TBAB为相转移催化剂的作用下,对乙苯的氧化反应条件进行了研究.研究发现乙苯在该催化体系中的最佳氧化条件依次是:水油体积比为3∶1;n(TBAB)∶n(乙苯)=1∶40;n(NHPI)∶n(乙苯)=1∶10,n(NHPI)∶n(CoSPc)=24∶1,反应温度110℃,氧气压力0.75 MPa,搅拌速率350 rpm,反应时间0.5 h.在最佳反应条件下乙苯转化率为60.6%,苯乙酮的选择性为95.2%,1-苯乙醇的选择性为4.5%,产物总选择性达到了99.7%.在此基础上延长反应时间并不能提高乙苯的转化率,苯乙酮的选择性也会下降,研究发现NHPI的分解是乙苯转化率不随反应时间的延长而提高的原因,而苯乙酮的过度氧化为苯甲酸是产物选择性下降的原因.     

过渡金属卟啉／高价盐体系催化分子氧对芳烃侧链氧化的研究

研究了四-全氟苯基卟啉过渡金属(TPFPPM,M=Co、Mn、Fe)/高价金属盐体系催化分子氧对烷基芳烃侧链氧化反应.结果表明,TPFPPCo催化乙苯及其衍生物的侧链氧化时,加入底物1/800的K2Cr2O7对反应有很好的促进作用,乙苯最高转化率达55.2%,苯乙酮收率为51.0%.该催化体系对于取代烷基苯,如正丙苯、正丁苯和对-溴乙苯也具有很好的催化效果.     

催化剂积炭失活宏观反应动力学的研究

 针对催化剂使用中积炭失活的一般性特点,借鉴库存集成电路长期稳定性预测研究结果,对现有的催化剂失活反应动力学方程进行了修正,并以渣油加氢脱硫反应为例加以验证. 修正后的失活反应动力学微分方程为-da/dt=kdad·tm,其积分式为a=1+(d-1)kdm+1tm+1-1d-1. 当m=0时,便成为常规的失活反应动力学方程; 当m≠0时,可将反应时间t视为一种虚拟反应组分.     

NHPI结合磺化酞菁钴催化的乙苯氧化反应

探索了一种由N-羟基邻苯二甲酰亚胺（NHPI）和磺化酞菁钴（CoSPc）组成的催化体系催化的将乙苯转化成相应氧化物有效且温和的方法．结果显示控制NHPI和乙苯物质的量比为0．050,NHPI和CoSPc物质的量比为6,反应温度90℃,是该氧化反应的最佳条件,在此条件下,乙苯在氧气中反应10h,乙苯转化率和苯乙酮选择性分...     

金属离子对Ru-Pt/γ-Al2O3催化剂上对氯硝基苯选择加氢反应的影响

 采用混合醇还原法制备了聚乙烯吡咯烷酮(PVP)稳定的Ru-Pt/γ-Al2O3双金属催化剂,考察了其催化对氯硝基苯(p-CNB)选择加氢反应的性能,探讨了反应温度、压力、第三金属离子的种类、添加量及添加方式对反应的影响. 结果表明,以Ru-Pt/γ-Al2O3为催化剂,在1.0 MPa和50 ℃的条件下反应1 h,p-CNB的转化率可达48.2%,生成对氯苯胺(p-CAN)的选择性为87.3%. 在反应体系中添加适量的Fe3+或Sn4+离子时,在相同的反应条件下,p-CNB的转化率和p-CAN的选择性分别提高到100%和99.0%. Fe3+或Sn4+的添加量及添加方式对p-CNB的转化率有较大的影响,加入Fe2+,Co2+和Ni2+离子也有利于提高催化剂的活性和选择性. Ru-Pt/γ-Al2O3催化剂体系对其它氯硝基苯的加氢反应也有明显的催化作用.     

乙苯与二甲苯在超临界压力下的热裂解研究

采用连续流动装置, 在压力为4 MPa, 温度分别在700, 750和780 ℃条件下, 开展了乙苯和二甲苯在超临界压力条件下热裂解反应的实验研究. 对乙苯和二甲苯裂解的气相产物, 采用在线气相色谱进行分析; 而裂解的液相产物则通过色质联用仪进行定量分析. 研究发现乙苯和二甲苯裂解的气相产物组成基本相同, 而液相产物组成相差较大, 但都是芳香烃类化合物. 乙苯和二甲苯的转化率都随温度升高而增加; 在相同温度下, 乙苯比二甲苯转化率高. 此外, 裂解过程并未发现明显的结焦现象, 说明纯芳香烃物质的热裂解并不会导致严重积炭. 同时, 本文还采用密度泛函方法在BHandHLYP/6-31+G(d, p)水平上, 对乙苯和甲苯分别进行结构优化并计算相关的键能. 计算结果表明: 乙苯侧链乙基中的C—C键的键能最小, 从而说明乙苯侧链烷基更容易发生断键反应, 理论结果很好地解释了乙苯比二甲苯裂解转化率高的实验现象. 本文的工作对燃料裂解结焦机理的重新认识有重要的意义.     

Method of kinetic analysis of photodegradation: nifedipine in solutions

A rate equation for photodegradation was derived from Lambert-Beer's law and Grotthus-Draper's law: -dc/dt=k1(1-exp(-(k2c+k3(c0-c))))k2c/(k2c+k3(c0-c)) where c is the concentration of reactant, c0 is the initial concentration of reactant, t is time, k1 is the rate constant, and k2 and k3 are the absorption coefficient of reactant and its photodegradation product, respectively. In a case where the photodegradation products have no photoabsorption, k3 assumes the value of zero in the above general equation. In a case where the photodegradation products have the same spectrum and molar absorptivity as that of the reactant, k3 assumes the value of k2, and hence the photodegradation is not a first-order reaction; however, the equation itself gives the pseudo-first-order reaction rate equation. In a case where the concentration of reactant is high enough, the equation approaches a zero-order reaction rate equation. The photodegradation rate of nifedipine in solutions under a germicidal lamp, near an ultraviolet fluorescent lamp and a fluorescent lamp was analyzed using the above equation. The photodegradation rate was directly proportional to the amount of light absorbed, and fitted well with the equation. The above theoretical equation was substantiated by the photodegradation of nifedipine, and hence is expected to apply to other photosensitive drugs.     

生物油酸酮类模化物与乙醇在HZSM-5上共裂化制备生物汽油

生物油酸类和酮类化合物具有较高的裂化活性,而使用分子蒸馏技术能将这些组分富集到蒸出馏分中,因此蒸出馏分相比原始生物油具有更好的裂化特性.为了模拟实际蒸出馏分的组成,本文将生物油模化物(羟基丙酮(HPO)、环戊酮和乙酸)进行配比混合,在固定床反应器上对其与乙醇的共裂化行为进行了研究,考察了不同反应温度和压力对混合反应物的转化率、粗汽油相的选择性和组成的影响.研究发现,当反应温度在340℃时,乙酸和乙醇的转化率分别仅为67.9%和74.4%,同时得到的油相产物中烃类含量仅为59.8%,并含有大量的含氧副产物.常压裂化同样生成了低品质的油相产物,同时油相选择性仅为10.8%.提高反应温度能促进反应物的转化,提高裂化过程中的脱氧效率,而提高反应压力对液体烃类的生成有明显的促进作用.在400℃和2MPa时,酸类和酮类都有良好的裂化表现,反应物接近完全转化,粗汽油相选择性达到31.5%,且全部由烃类组成,其中芳香烃含量高达91.5%.此外,反应后催化剂表征和稳定性测试结果表明,催化剂在较长时间反应后会失活,但通过催化剂再生能够很好地恢复催化剂活性.     

Friedel–Crafts alkylation reactions in pyridinium-based ionic liquids

The Friedel–Crafts alkylations of benzene in pyridinium-based ionic liquids (ILs) were investigated. The effects of catalyst–IL composition, reactant composition, quantity of catalyst and reaction temperature on this reaction were studied. The reactions were found to proceed under mild conditions with conversion; a simple product isolation procedure was achieved. The ILs rendered this reaction green characteristics. The ILs could also be recycled and reused as opposed to traditional solvent–catalyst systems.     

含氮合成气在三相淤浆床-固定床中直接合成二甲醚

在三相淤浆床－固定床反应装置中,研究含氮合成气直接合成二甲醚。使用双功能混合催化剂,粒度为0.15 mm～0.18 mm。在220 ℃～260 ℃、3.0 MPa～7.0 MPa、空速1 000 mL·g-1·h-1时考察了温度、压力及两种反应器中催化剂的装填比例对CO转化率及二甲醚选择性的影响。结果表明,一氧化碳转化率随反应压力的增加而提高,随着温度升高二甲醚的选择性变化不大,CO转化率的升高较明显,因此在催化剂活性适宜的温度范围内,该反应装置可以采用较高的反应温度。当260 ℃、7.0 MPa、三相床与固定床中催化剂比例为1∶1时,CO的转化率可达84.5％,二甲醚的选择性为78.7％。淤浆床－固定床反应装置具有操作稳定性好、CO转化率高的优点。催化剂在该装置中反应370 h活性没有明显下降。     

A LUMPING KINETICS FOR MODIFIED FT REFORMING PROCESS Ⅱ.EXPERIMENTAL AND KINETICS PARAMETERS ESTIMATION

IntroductionInthefirstpatofacsinvestigation,athree-lumpmodelisproposedforthereaCtionsystemofMFTrefonning.However,theveryimportantworkforthekineticsanalysisistOd~inetheparametersinthekineticsequations.Becausethereisnopriormethodfordotennnungthesep~ers,expe…     

Conversion enhancement of tubular fixed-bed reactor for Fischer-Tropsch synthesis using static mixer

Recently,Fischer-Tropsch synthesis(FTS) has become an interesting technology because of its potential role in producing biofuels via Biomassto-Liquids(BTL) processes.In Fischer-Tropsch(FT) section,biomass-derived syngas,mainly composed of a mixture of carbon monoxide(CO) and hydrogen(H2),is converted into various forms of hydrocarbon products over a catalyst at specified temperature and pressure.Fixed-bed reactors are typically used for these processes as conventional FT reactors.The fixed-bed or packed-bed type reactor has its drawbacks,which are heat transfer limitation,i.e.a hot spot problem involved highly exothermic characteristics of FT reaction,and mass transfer limitation due to the condensation of liquid hydrocarbon products occurred on catalyst surface.This work is initiated to develop a new chemical reactor design in which a better distribution of gaseous reactants and hydrocarbon products could be achieved,and led to higher throughput and conversion.The main goal of the research is the enhancement of a fixed-bed reactor,focusing on the application of KenicsTM static mixer insertion in the tubular packed-bed reactor.Two FTS experiments were carried out using two reactors i.e.,with and without static mixer insertion within catalytic beds.The modeled syngas used was a mixed gas composed of H2/CO in 2:1 molar ratio that was fed at the rate of 30mL(STP)min1(GHSV≈136mL g1 cat h1) into the fixed Ru supported aluminum catalyst bed of weight 13.3g.The reaction was carried out at 180℃ and atmospheric pressure continuously for 36h for both experiments.Both transient and steady-state conversions(in terms of time on stream) were reported.The results revealed that the steady-state CO conversion for the case using the static mixer was approximately 3.5 times higher than that of the case without static mixer.In both cases,the values of chain growth probability of hydrocarbon products(α) for Fischer-Tropsch synthesis were 0.92 and 0.89 for the case with and without static mixer,respectively.     

Synthesis and characterization of a novel hydroxypolyether blocked polydimethylsiloxane PEO-b-PDMS-b-PEO

A novel hydroxypolyether blocked polydimethylsiloxane, poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl poly（ethylene oxide） （PEO-b-PDMS-b-PEO） was synthesized by simple hydrosilation reaction of poly（ethylene glycol） monoallyl ether with α,ω-dihydrogen terminated PDMS （HPDMS）. Fourier transform infrared spectroscopy （FTIR） and IH NMR were used to identify the structure of PEO-b-PDMS-b-PEO and intermediate product HPDMS. Based on the effect investigations of temperature, reactant molar ratio, catalyst and time on the hydrosilation, it was found that the conversion of Si-H bond to SiC bond increased with the increase of catalyst and time, and the reaction completed when the content of catalyst was 22μg/g and the time was 5 h, respectively. Urethane reaction of OH and NCO group confirms that PEO-b-PDMS-b-PEO is more reactive toward to diisocyanate than α,ω-dihydroxylbutyl terminated PDMS.     

Enzyme reactors in unsegmented flow injection analysis

The design of immobilized-enzyme reactors for use in flow injection analysis is discussed. The reactors should be optimized for a short residence time and a very high (> 99.9%) conversion of substrate to products. Selection of carrier and immobilization method is important in order to increase the amount of active enzyme per unit volume. The effeciency of the reactor can be increased by decreasing the particle size in packed-bed reactors and the radius of open tubular reactors. The maximum inherent rate constant that can be obtained under optimal conditions is estimated for a number of enzymes of analytical interest; it is shown that with high rate constants and small particle diamters, residence times less than seconds can be obtained. Some applications of immobilized-enzyme reactors in flow systems are reviewed.     

Kinetics of the NCN + NO reaction over a broad temperature and pressure range

Rate coefficients for the reaction (3)NCN + NO → products (R3) were measured in the temperature range 251-487 K at pressures from 10 mbar up to 50 bar with helium as the bath gas. The experiments were carried out in slow-flow reactors by using pulsed excimer laser photolysis of NCN(3) at 193 or 248 nm for the production of NCN. Pseudo-first-order conditions ([NCN](0) ? NO) were applied, and NCN was detected time-resolved by resonant laser-induced fluorescence excited near 329 nm. The measurements at the highest pressures yielded values of k(3) ～ 8 × 10(-12) cm(3) s(-1) virtually independent of temperature and pressure, which indicates a substantially smaller high-pressure limiting value of k(3) than predicted in earlier works. Our experiments at pressures below 1 bar confirm the negative temperature and positive pressure dependence of the rate coefficient k(3) found in previous investigations. The falloff behavior of k(3) was rationalized by a master equation analysis based on a barrierless association step (3)NCN + NO ? NCNNO((2)A″) followed by a fast internal conversion NCNNO((2)A″) ? NCNNO((2)A'). From 251-487 K and above 30 mbar, the rate coefficient k(3) is well represented by a Troe parametrization for a recombination/dissociation reaction, k(3)(T,P) = k(4)(∞)k(4)(0)[M]F(k(4)(0)[M] + k(4)(∞))(-1), where k(4) represents the rate coefficient for the recombination reaction (3)NCN + NO. The following parameters were determined (30% estimated error of the absolute value of k(3)): k(4)(0)[M=He] = 1.91 × 10(-30)(T/300 K)(-3.3) cm(6) s(-1)[He], k(4)(∞) = 1.12 × 10(-11) exp(-23 K/T) cm(3) s(-1), and F(C) = 0.28 exp(173 K/T).     

乙酸盐上二氧化碳和二醇合成环状碳酸酯

在乙腈体系中,以不同的乙酸盐作催化剂,研究了CO2与二醇合成环状碳酸酯的反应.乙腈在反应过程中不仅是溶剂,而且还起到了脱水剂的作用,促进了反应的进行.以1,2-丙二醇为反应物对催化剂进行筛选,发现无水乙酸锌具有最高的催化活性.在无水乙酸锌上考察了二氧化碳和不同二醇的反应,结果表明,五元环碳酸酯的产率明显高于六元环碳酸酯,其中碳酸丙烯酯的产率最高.以1,2-丙二醇为反应基质,无水乙酸锌为催化剂,确定了最佳反应条件,1,2-丙二醇100 mmol,乙睛10 mL,催化剂2.5 mmol,反应压力10 MPa,温度170 ℃,反应12 h.在此条件下,碳酸丙烯酯的产率达到了24.2%,1,2-丙二醇的转化率为38.9%.