醋酸对环己烷气相氧化脱氢产物选择性影响的研究

以α1-VOPO4相为催化剂, 在环己烷气相氧化脱氢反应中, 通过在原料中加入醋酸可控制反应产物的分布. 研究了不同醋酸量对目标产物选择性的影响, 醋酸在反应体系中优于环己烷吸附在α1-VOPO4催化剂的表面上, 使催化剂表面形成孤立的活性中心, 避免了产物环己烯的深度氧化. 反应温度为450 ℃, 醋酸与环己烷的摩尔比为12.9∶1时, 环己烷的转化率为6.9%, 环己烯的选择性为100%.     

金属酞菁催化氧化β-甲基萘的研究

研究了金属酞菁催化氧化β-甲基萘制备甲基萘醌的反应,考察了催化剂种类、氧化剂种类、投料比、反应温度和时间等对反应的影响。结果表明双核磺化酞菁铜表现出良好的催化活性,在双氧水为氧化剂,醋酸为溶剂的条件下,催化剂质量分数为15%、双氧水与甲基萘的摩尔比为5∶1、反应温度为60℃、时间为7 h,目标产物的收率最高达到47.8%。     

二醋酸纤维素接枝丙交酯共聚物的合成与表征

以二醋酸纤维素为接枝骨架,在辛酸亚锡的催化下,通过L-丙交酯的开环接枝聚合反应,合成了二醋酸纤维素和聚丙交酯接枝共聚物(CDA-g-PLA),并采用GPC、FTIR、1H-NMR和DSC对接枝共聚物进行表征.研究了原料质量比、催化剂用量、反应时间、反应温度对单体转化率(C%)、接枝率(G%)的影响.结果表明:反应温度150℃,单体丙交酯与二醋酸纤维素质量比为4:1,反应时间30min,催化剂辛酸亚锡与二醋酸纤维素的质量比为1%时,产物的接枝率较高.     

微波辐射磷钨酸催化合成乙酸丁酯

以磷钨酸作催化剂 ,4A分子筛为脱水剂 ,采用微波辐射技术 ,用乙酸和丁醇直接合成乙酸丁酯 .考察了催化剂用量、微波辐射功率、时间、乙酸丁醇比对反应转化率的影响 .最佳反应条件为 :乙酸与磷钨酸的物质的量的比为 1∶0 .0 0 16 6 4,微波辐射功率及时间为 335W ,15min ,乙酸丁醇的物质的量的比为 1∶1.5 .此条件下转化率为 96 % .     

超临界二氧化碳中亚胺类共价有机骨架材料COF-LZU1的合成与表征

研究了超临界流体技术在共价有机骨架材料（COF）合成中的应用,以均苯三甲醛和对苯二胺为原料,N,N-二甲基甲酰胺为共溶剂,醋酸为催化剂,在超临界二氧化碳（scCO₂）中合成了亚胺类共价有机骨架材料COF-LZU1.考察了共溶剂、反应温度、反应压力、反应时间、醋酸含量和反应物摩尔比对COF-LZU1材料的晶体结构和微观形貌的影响.实验结果表明,反应温度的升高有利于提高scCO₂的传质速率及增加反应物在scCO₂中的溶解度,从而促进反应的进行;反应时间的延长有利于晶体的成熟和结晶度的提高;醋酸不仅是反应催化剂,还具有形貌导向剂的作用,通过改变醋酸用量分别获得了球状、块状和棒状形貌的COF-LZU1;反应物中对苯二胺含量过高会干扰反应过程中醛基与氨基的有序结合,导致结晶度的降低以及形貌规整程度的下降.在反应温度为60℃,反应压力为20 MPa,反应时间为6 h,均苯三甲醛与对苯二胺摩尔比为1：1.5,醋酸（3 mol/L）与N,N-二甲基甲酰胺体积比为1：1的条件下,制备的COF-LZU1呈现截面直径为80 nm的纳米棒形貌,具有良好的结晶度和优异的热稳定性,热分解温度高达550℃.本文首次在超临界环境中制备了COFs材料,为COFs的绿色合成提供了新途径.     

杂多酸的固载化及其催化合成醋酸脂肪醇酯

本文研究了活性炭对磷钼钨杂多酸的固载化方法 ,结果发现使用蒸发法进行固载 ,当活性炭与磷钼钨杂多酸的质量比为 1∶0 75时 ,所得固载型杂多酸的催化效果最好。利用所制备的活性炭固载杂多酸型催化剂探讨了醋酸与各种一元脂肪醇的酯化反应 ,发现该催化剂对醋酸脂肪醇酯的合成均具有较好的催化效果 ,并且重复使用 4次 ,催化活性仍较高     

全氟磺酸树脂催化剂在酯化反应中的应用

全氟磺酸树脂是一种全氟型的高聚物,它具有良好的化学稳定性和热稳定性。分子中氟原子的强烈电负性使磺酸呈现很强的酸性,有极强的催化活性。Olah等用这种固体超强酸树脂作催化剂,对芳环的硝化、Friedel-Crafts反应、烯烃和炔烃的水化、重排和酯化等反应进行了研究。在酯化反应中他们将醋酸和醇(克分子比为3:1)在催化剂存在下迴流,得到酯的产率为40％—60%。本文用醋酸和稍过量的醇在催化剂存在下迴流进     

KF-Al_2O_3催化合成1-(4-溴丁基)-咪唑盐酸盐

报道了用KF -Al2 O3 作催化剂 ,合成 1- (4-溴丁基 ) -咪唑盐酸盐的新方法 ,并考察了诸因素对产率的影响 ,找出了最佳的反应条件 .最佳的反应条件为 :咪唑与二溴丁烷的摩尔比为 1∶1.2 ,催化剂与反应物总质量之比为 1∶1,反应温度为 18℃～ 2 5℃ .     

固体酸SO42-/SiO2-TiO2催化合成乙酰水杨酸研究

以水杨酸和乙酸酐为原料,用SO■/SiO_2-TiO_2固体酸为催化合成乙酰水杨酸,考察了TiO_2与SiO_2质量比、硫酸浸渍量、浸渍时间、煅烧温度等因素对乙酰水杨酸产率影响,通过红外光谱、扫描电镜和激光粒度仪对催化剂或合成产物进行了表征。得到最佳反应条件:SiO_2:TiO_2质量比为0.4:1、硫酸浸渍量与TiO_2质量比为0.49:1、浸渍时间为26 h、煅烧温度为400℃,该条件下制备的固体酸催化合成乙酰水杨酸产率为65%。该催化剂具有易与反应体系分离,对设备腐蚀性小,可再生等优点。     

以固体超强酸SO4^2-／ZrO2-Fe2O3催化合成醋酸异戊酯

以合成醋酸异戊酯为探针反应,筛选出制备固体超强酸SO2-4 /ZrO2- Fe2O3 (SZF -1 )的最佳工艺条件为:ZrOCl2·8H2O9. 7g, FeCl3·6H2O16. 2g, 常温陈化24h, 0. 5mol·L-1 H2SO4 (15mL·g-1 )浸泡5h, 550℃焙烧3h。以SZF 1为催化剂合成醋酸异戊酯的反应条件为:异戊醇200mmol, n(异戊醇)∶n(醋酸) =1. 0∶1. 3, SZF -1 1g(反应物总质量的3% ), 环己烷15mL, 回流反应3h, 酯化率93. 47%。催化剂连续使用6次后酯化率仍在70%以上。     

醋酸溶液中Pd-CuPc/Y催化甲烷选择氧化制甲醇

以氯化铜、钼酸铵、苯酐、氯化铵、尿素和NaY分子筛为原料,采用苯酐-尿素法制备了酞菁铜/分子筛复合物CuPc/Y.采用等体积浸渍法将金属钯担载在CuPc/Y上制备了Pd-CuPc/Y催化剂,并在醋酸水溶液中考察了其催化甲烷选择氧化合成甲醇反应的性能,结果表明,催化性能与反应温度、溶剂中CH₃COOH与H₂O的混合比例、对苯醌用量、反应时间等因素有关,在0.5%Pd-0.5%CuPc/Y添加量0.5 g、CH₃COOH与H₂O体积比4∶1、对苯醌用量1 000 μmol、反应时间3 h、反应温度150 ℃的条件下,甲醇的最佳生成量为1 840 μmol.Pd-CuPc/Y催化剂可以多次循环使用,但由于催化剂流失和催化剂表面的钯粒子聚集的原因,循环使用后的催化剂催化活性有所下降.Pd-CuPc/Y在醋酸溶液中催化甲烷选择氧化合成甲醇是亲电取代反应和活性氧物种氧化共同作用的结果.     

固体超强酸ZrO_2/S_2O_8~(2-)催化合成乙酸正己酯

以固体超强酸ZrO2/S2O2-8为催化剂,乙酸和正己醇为原料合成了乙酸正己酯,考察了反应条件对酯化率的影响.结果表明,最佳反应条件为:醇酸摩尔比1.4,催化剂用量0.5g(当乙酸用量为0.1mol时),带水剂苯15mL,在110～118℃反应1.5h,其酯化率达92%以上.该方法的优点是酯化率高,催化剂可重复使用且基本不腐蚀设备.     

Esterification reaction kinetics of acetic acid and n-pentanol catalyzed by sulfated zirconia

This study reports experimental data and kinetic modeling of acetic acid esterification with n-pentanol using sulfated zirconia as a catalyst. Reactions were carried out in an isothermal well-mixed batch reactor at different temperatures (50-80°C), n-pentanol to acid molar ratios (1:1-3:1), and catalyst loadings (5-10 wt% in relation to the total amount of acetic acid). The reaction mechanism regarding the heterogeneous catalysis was evaluated considering pseudo-homogeneous, Eley–Rideal, and Langmuir–Hinshelwood model approaches. The reaction mixture was considered a nonideal solution and the UNIQUAC thermodynamic model was used to take into account the nonidealities in the liquid phase. The results obtained indicated that increases in the temperature and catalyst loading increased the product formation, while changes in the n-pentanol to acetic acid molar ratio showed no significant effect. The estimated enthalpy of the reaction was −8.49 kJ mol⁻¹, suggesting a slightly exothermic reaction. The Eley–Rideal model, with acetic acid adsorbed on the catalyst as the limiting step, was found to be the most significant reaction mechanism.     

Selective Oxidation of Propane by Lattice Oxygen of Vanadium-Phosphorous Oxide in a Pulse Reactor

Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide (VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and the re-oxidation of catalyst were implemented alternately in the presence of water vapor. The principal products are acrylic acid (AA),acetic acid (HAc), and carbon oxides. In addition, small amounts of C1 and C2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4-2.2. The active oxygen species are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. lattice oxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulating fluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reaction temperature in a pulse reactor were found almost the same as in a steady-state flow reactor. That is, as the reaction temperature increases, propane conversion and the amount of C1 C2 hydrocarbons in the product increase steadily, while selectivity to acrylic acid and to acetic acid increase prior to 350℃ then begin to drop at temperatures higher than 350℃, and yields of acrylic acid and of acetic acid attained maximum at about 400℃. The maximum yields of acrylic acid and of acetic acid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When theamount of propane pulsed decreases or the amount of catalyst loaded increases, the conversion increases but the selectivity decreases. Increasing the flow rate of carrier gases causes the conversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bed reactor, it is hard to obtainhigh selectivity at a high reaction conversion due to the further degradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen. The catalytic performance can be improved inthe presence of excess propane. Propylene can be oxidized by lattice oxygen of VPO catalyst at 250℃, nevertheless, selectivity to AA and to HAc are even lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1-0.83:1) though the oxidation products are the same as from propane.     

乙酸异戊酯的合成

以乙酸和异戊醇作为原料,利用SnCl4催化作用下的酯化反应合成了乙酸异戊酯;研究了反应时间、酸醇的物质的量之比、催化剂用量、带水剂用量等因素对产物收率的影响,并确定了优化反应条件.结果表明,优化反应条件为:反应时间60min,酸醇物质的量之比1∶0.8(乙酸5.76mL),催化剂用量0.35g,带水剂用量10mL.在优化反应条件下,产物收率最高可达86.3%.     

脱铝超稳Y沸石催化合成乙酸正丁酯研究

研究了脱铝超稳Y沸石催化乙酸与正丁醇的酯化反应。考察了催化剂硅铝比，催化剂用量，反应物配比，反应时间等因素对反应的影响。在适宜的反应条件下乙酸酯化率可达98．0％，且催化剂可重复使用。     

FeCl3/Acetic Acid-mediated Reverse Atom Transfer Radical Polymerization of Acrylonitrile

Reverse atom transfer radical polymerization (RATRP) has been successfully applied in the synthesis of polyacrylonitrile (PAN) with FeCl₃/acetic acid as catalyst in the presence of conventional initiator azobisisobutyronitrile (AIBN) at 65°C in N,N-dimethylformamide (DMF). A FeCl₃ to acetic acid ratio of 1:2 not only gave better control on polymer's molecular weight and its distribution, but also provided a rapid polymerization rate compared with any other molar ratio of FeCl₃ to acetic acid. The polymerization rate increased with increasing temperature and the apparent activation energy was calculated to be 80.6 kJ·mol^?1. In comparison with dimethyl sulfoxide, acetonitrile, cyclohexanone and ethyl acetate, DMF was considered to be the best solvent of the polymerization for its polarity. Analysis of ¹H-NMR further confirmed the living nature of the polymerization.     

乙酸选择性加氢制乙醇反应性能研究

在固定床反应器上考察了反应温度、反应压力、乙酸(HAC)液体进料空速、H_2/HAC(总气体空速GHSV或H_2流量)对乙酸选择性加氢制乙醇反应的影响,研究了乙酸转化率、产物选择性、乙醇时空收率的变化规律,验证了自主开发催化剂的稳定性。结果表明,副产物的选择性受反应条件的影响,选择合适的反应条件可以抑制乙酸乙酯和丙酮的生成。原料与催化剂床层接触时间小于5s时,可以避免发生乙酸加氢分解脱羰反应生成甲烷气相产物,也避免了乙醇的进一步反应生成乙烷。在反应温度为280℃,反应压力为2.5 MPa,乙酸进料液时空速为0.72 h~(-1),H_2/HAC(mol ratio)为16的条件下,乙酸乙酯选择性为6%。900 h长周期实验表明,自主开发催化剂具有较好的工业应用前景。     

Synthesis of Terpineol from Alpha-Pinene Catalyzed by α-Hydroxy Acids

We report the use of five alpha-hydroxy acids (citric, tartaric, mandelic, lactic and glycolic acids) as catalysts in the synthesis of terpineol from alpha-pinene. The study found that the hydration rate of pinene was slow when only catalyzed by alpha-hydroxyl acids. Ternary composite catalysts, composed of AHAs, phosphoric acid, and acetic acid, had a good catalytic performance. The reaction step was hydrolysis of the intermediate terpinyl acetate, which yielded terpineol. The optimal reaction conditions were as follows: alpha-pinene, acetic acid, water, citric acid, and phosphoric acid, at a mass ratio of 1:2.5:1:(0.1–0.05):0.05, a reaction temperature of 70 °C, and a reaction time of 12–15 h. The conversion of alpha-pinene was 96%, the content of alpha-terpineol was 46.9%, and the selectivity of alpha-terpineol was 48.1%. In addition, the catalytic performance of monolayer graphene oxide and its composite catalyst with citric acid was studied, with acetic acid used as an additive.