丙烯醛/氨反应制备3-甲基吡啶的研究进展

综述了丙烯醛/氨反应制备3-甲基吡啶的方法,主要包括液相釜式反应法、气相固定床反应法和气相流化床反应法3种。介绍了这些方法的工艺特点,评述了其优缺点及所涉及的催化剂。对丙烯醛/氨反应制备3-甲基吡啶过程所需要着重解决的问题进行了归纳总结。并简介了3-甲基吡啶的合成机理。同时,对于丙烯醛/氨反应制备3-甲基吡啶技术的发展前景也进行了展望,认为介孔材料和固体酸催化剂应用于该反应及合成机理的深入研究是未来的发展方向之一。     

丙烯醛温和液相反应制备3-甲基吡啶工艺

以丙烯醛为原料,通过单因素实验,建立了优化的温和液相反应合成3-甲基吡啶的优化工艺条件：以乙二醇单丁醚为溶剂,反应温度140℃,料液比n(丙烯醛):n(乙二醇单丁醚)=1:33,n(丙烯醛):n(乙酸铵)=1:8,w(丙烯醛正丁酸溶液)=8%,m(丙烯醛):m(SO24-/TiO2-HZSM-5催化剂)=1:1.4。在优化条件下,实现了丙烯醛转化率100%,3-甲基吡啶选择性49.92%。     

3-甲基吡啶合成工艺的研究进展

吡啶碱,包括吡啶和甲基吡啶（如2-甲基吡啶、3-甲基吡啶和4-甲基吡啶等）,是一类典型的含氮化合物,常应用于维生素、杀虫剂等方面,尤其是3-甲基吡啶。综述了3-甲基吡啶合成工艺的研究现状,对其优缺点进行分析,归纳催化剂失活的原因以及再生方法的研究状况。最后,提出甘油/氨为反应原料是合成3-甲基吡啶的理想路线,具有绿色环保、来源可再生和成本低等优点,必将成为未来的发展趋势,展望该工艺今后重点研究方向是开发高性能的催化剂。     

3-甲基吡啶合成工艺路线进展

简要介绍了3-甲基吡啶的用途、生产状况。总结了国内外以不同原料合成3-甲基吡啶的方法,包括丙烯醛氨法、醛氨法、三烯丙基胺法、2-甲基戊二腈法、吡啶甲基化法等5大类12种方法。并对醛氨法和最近研究热点吡啶甲基化法合成3-甲基吡啶作了详细介绍,指出开发高转化率和高选择性的催化剂是3-甲基口比啶合成工艺的关键。     

吡啶和3-甲基吡啶的合成工艺研究

以固定床反应器,Co-Pb/ZSM-5分子筛为催化剂,以甲醛、乙醛、氨为原料合成吡啶和3-甲基吡啶。考查了催化剂中金属元素摩尔配比、催化剂用量、原料配比、反应条件（温度、压力）对反应的影响,筛选出最优反应条件：Co∶Pb摩尔比0.7,催化剂用量3%,甲醛∶乙醛∶氨=1.5∶1∶3,反应温度400℃,反应压力1 MPa条件下,吡啶的收率达78.5%,3-甲基吡啶收率达18.3%。该工艺路线简单,安全性高,收率高,适合工业化生产。     

醛/氨反应合成吡啶碱机理

在常压釜式反应器中,以乙酸为溶剂,开展了乙酸铵(氨源)与甲醛、乙醛和丙烯醛中的一种或多种反应制备吡啶碱的研究。通过Hückel和Mulliken模型的量子化学和热力学计算,分析了丙烯醛和反应中间体丙烯亚胺的构型和电荷,考察了生成中间体二氢吡啶和产物3-甲基吡啶过程中的静电相互作用、前线分子轨道和能量变化,从而提出了丙烯醛/氨合成3-甲基吡啶的反应机理,并总结了醛/氨反应制吡啶碱反应的一般规律。理论预测的产物组成与实验结果具有良好的一致性。     

由丙烯醛合成3-甲基吡啶

3-甲基吡啶是合成烟酸的主要原料,但目前国内尚不能生产。为了解决国内的需要,山东省化学研究所采用丙烯醛法进行了研究。试验表明:以F-Al_2O_3(用氟处理三氧化二铝)为催化剂,以环氧丙烷为年释剂,使丙烯醛与氨在气相固定床装置中合成3-甲基吡啶取得了较好结果。其操作方法是;将含95％以上丙烯醛与环     

哌虫啶及其中间体新合成方法研究

研究新烟碱类杀虫剂哌虫啶稠环化、醚化工艺及其中间体2-氯-2-氯甲基-4-氰基丁醛的新合成方法。稠环化、醚化工艺分别采用三乙胺和对甲苯磺酸为催化剂,选择适当投料比、反应温度、反应时间和溶剂以提高反应收率。研究丙烯醛经氯化,再与丙烯腈加成制备2-氯-2-氯甲基-4-氰基丁醛的新合成方法,与美国瑞利公司开发的丙烯醛–环戊二烯合成路线相比,减少了反应步骤,具有路线短、收率高的优点。     

Y/ZSM-5分子筛催化丙烯醛二乙缩醛和氨合成3-甲基吡啶

合成3-甲基吡啶的催化剂主要为负载型ZSM-5,很少涉及组合分子筛。使用机械研磨-浸渍手段合成Y/ZSM-5分子筛,并用于气相条件下丙烯醛二乙缩醛和氨催化合成3-甲基吡啶。采用多种手段对催化剂进行了较详细的表征。结果表明,与Y和ZSM-5相比,Y/ZSM-5分子筛拥有更高的外表面积和更低的酸量。这些因素使得Y/ZSM-5具有更高的催化活性。本研究提供了一种新型催化剂合成3-甲基吡啶。     

3-氰基吡啶合成路线及其催化剂研究概述

目前我国的3-氰基吡啶主要依赖进口,为了缓解国内供需矛盾,寻找合理的3-氰基吡啶工业化生产路线已经迫在眉睫。综述了3-氰基吡啶的合成路线,包括烟酰胺法,2-甲基戊二腈氧化法以及3-甲基哌啶,3-甲基吡啶氨氧化法。着重介绍了氨氧化法的反应机理及其催化剂的催化活性。在对几类钒系以及非钒系催化剂进行探讨的基础上,提出了一种新型的纳米分子筛催化剂,并对其工业应用前景进行了展望。     

丙烯醛水合加氢法制备1,3-丙二醇

简述了聚对苯二甲酸丙二酯 ( PTT)的特性、我国 PTT的发展状况 ,阐述了纤维级 1,3-丙二醇的研制、开发与生产对 PTT发展的重要性。着重介绍丙烯醛水合加氢法生产 1,3-丙二醇的工艺 ,并对丙烯醛水合反应、3-羟基丙醛加氢反应、4-氧代 -1,7-庚二醇水解反应、1,3-丙二醇提纯方法以及反应催化剂和反应条件进行了探讨     

Conversion of Glycerol to Acrolein in the Presence of WO3/ZrO2 Catalysts

Dehydration of glycerol to acrolein was performed on WO₃/ZrO₂ solid heterogeneous catalysts in a continuous flow fixed bed reactor. A maximum of 75% acrolein selectivity was achieved at 100% conversion of glycerol. The acrolein selectivity correlates with the concentration of weak acidic sites of the WO₃/ZrO₂ catalysts that were free of basic sites.     

Synthesis of acrolein by gas‐phase dehydration of glycerol over silica supported Bronsted acidic ionic liquid catalysts

BACKGROUND: Glycerol has become readily available as a byproduct from the biodiesel industry. High functionality and relatively low price make it a potential building block to produce value‐added derivatives such as acrolein. RESULTS: Dehydration of glycerol to acrolein was performed over several silica supported Brønsted acidic ionic liquids as catalysts. All the catalysts prepared were active for the synthesis of acrolein (conversion of glycerol was observed in the range 35–90% with selectivity to acrolein in the range 29–58%). CONCLUSIONS: Catalyst prepared from triphenyl (3‐sulfopropyl) phosphonium 4‐methylbenzenesulfonate gave good activity and selectivity at 4 h reaction time. The conversion of glycerol decreased with increase in glycerol concentration. Higher temperature (325 °C) resulted in significantly lower conversion as well as selectivity to acrolein. With the use of two additional traps cooled to ? 7 °C, the selectivity to acrolein increased significantly for good catalysts. Copyright © 2010 Society of Chemical Industry     

High-performance phosphate supported on HZSM-5 catalyst for dehydration of glycerol to acrolein

The purpose of this study is to increase acrolein yield and capability of coking resistance in the reaction of glycerol dehydration to acrolein by assembling metal phosphate supported on HZSM-5 catalyst.The as-prepared catalysts were characterized by XRD,SEM,EDS,BET,NH3-TPD,CO2-TPD and Py-IR techniques.It was found that metal phosphate species were incorporated into the porous structure of HZSM-5 zeolites,thus influencing the surface and textural physico-chemical properties of the supporters.The alkaline-treated HZSM-5 catalyst promoted the dispersion of phosphate species on the carriers.Moreover,the amount of strong aridity was tremendously improved by adding the different metal hydrophosphates and the catalysts show high catalytic activity.In this present work,the Sn1/4H2PO4/HZSM-5 catalyst exhibited good performance in the catalytic activity and coking resistant ability,which resulted in a high acrolein yield of 83％ initially and acrolein yield of 68％ after 30 h.The aridity,especially the ratio of strong to weak acid,plays an important role in promoting acrolein yield and stability simultaneously.     

Lattice oxide ion-transfer effect demonstrated in the selective oxidation of propene over silica-supported bismuth molybdate catalysts

Silica-supported bismuth molybdate catalysts were prepared by impregnation in a highly dispersed state and by coprecipitation in a largely crystallized state. Their catalytic behavior was investigated in the oxidation of propene to acrolein. The highly dispersed bismuth molybdate catalysts on silica were found to be intrinsically active but poorly selective to acrolein. When we increased the loading amount the oxidation activity drastically increased. The poor acrolein selectivity of this catalyst was improved by continuous use in the catalytic oxidation for making the particle size of the dispersed bismuth molybdate larger. The catalytic activity and selectivity were little influenced by the loading amount in the cases of the coprecipitated catalysts. The results demonstrate that, for the activity and selectivity, bismuth molybdate catalysts need to be of a certain particle size which can provide sufficient lattice oxide ions during the catalytic redox cycle.     

生物柴油副产物粗甘油催化氧化脱水制备丙烯酸

用生物柴油副产物粗甘油催化氧化脱水制丙烯酸,该过程耦合了甘油脱水制丙烯醛和丙烯醛选择性氧化制备丙烯酸两步反应。结果表明,在甘油脱水反应中,使用Cs3PW12O40, P-ZSM-5和Co0.5H2PO4/SiO2等固体酸催化剂,可得到较高的丙烯醛收率(最高86.9%)。利用上述催化剂和MoVW基氧化催化剂,在脱水/氧化双催化剂床层构型反应器中,以甘油为原料合成丙烯酸的收率达50%~80%,直接加入粗甘油可获得相似的丙烯酸收率。     

Gas-phase dehydration of glycerol over commercial Pt/γ-Al2O3 catalysts

Gas-phase dehydration of glycerol to produce acrolein was investigated over commercial catalysts based onγ-Al2O3, viz. A-64, A-56, I-62, AP-10, AP-56, AP-64 and KR-104. To understand the effect of Cl?anions, HCl-impregnated sup-ports have been investigated in the dehydration reaction of glycerol at 375 °C. For comparison, various H-zeolites were also examined. It was found that the glycerol conversion over the solid acid catalysts was strongly dependent on their acidity and surface area. And the relationship between the catalytic activity and the acidity of the catalysts was discussed. The outstanding properties of Pt/γ-Al2O3 catalyst systems for the dehydration of glycerol were revealed. Pt/γ-Al2O3 catalyst (AP-64) showed the highest catalytic activity after 50 h of reaction with an acrolein selectivity of 65%at a conversion of glycerol of 90%. Based on these results, catalysts based onγ-Al2O3 appear to be most promising for gas phase dehydration of glycerol.     

Gas-phase conversion of glycerol over mixed metal oxide catalysts

A series of aluminophosphates (APO) catalysts with Ce, Cu, Cr, Fe, Mn, Mo, V, and W oxide loading at a constant ratio M: Al = 1: 10 and PO₄: Al = 1: 12 were prepared and characterized by N₂ physisorption, XRD and NH₃-TPD. Gas-phase dehydration of glycerol to produce acrolein and acetol was investigated at 280°C in presence of water. Conversion and product distribution depended on the intrinsic acidity and the type of transition metal oxide. Best selectivity to acrolein (52–58%) was obtained for W- und Mo-APO catalysts. Cr-, Mn- and W- oxide containing catalysts enhanced the formation of phenol, acetaldehyde and CO _x . The catalysts containing V- and Fe-oxide promoted the formation of allyl alcohol. All catalysts showed long term stability, which can be attributed to the redox ability of the metal oxides that enhances the removal of coke deposits. The investigated catalyst a specially W-APO and Mo-APO can be recommended for further controlled trials on a pilot plant for selective conversion of water solution of glycerol to acrolein and/or acetol.