生物质甘油催化转化为羟基丙酮

探索了生物质甘油在铜铬催化剂作用下催化转化为羟基丙酮的反应条件,采用乙醇为溶剂,考察了甘油浓度、催化剂用量和反应温度等因素的影响。较优反应条件:反应温度240℃,采用连续滴样的进样方式,甘油浓度80%,未还原的铜铬催化剂[n(Cu)∶n(Cr)=1]用量为原料质量的2.5%,甘油转化率和羟基丙酮选择性分别达到95.4%和89.9%。     

甘油选择性脱水的海绵铜基催化剂制备和表征

采用湿混法制备了氧化物修饰的海绵铜基甘油脱水催化剂。Cu/Mg O催化剂催化甘油脱水表现出了优良的活性和选择性,借助于粉末X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、N2吸附-脱附(BET)、CO2程序升温脱附(CO2-TPD)和热重-差示扫描量热(TG-DSC)等技术对Cu/Mg O进行了表征,并考察了该催化剂在无溶剂条件下催化甘油脱水至羟基丙酮的性能。结果表明:Mg O的修饰未改变海绵铜的骨架,且形成了Cu-Mg O相,其催化甘油脱水的活性和选择性与Cu和Mg O间相互匹配密切相关。当含Cu 8%(质量分数)的催化剂用量为1.0 g(为反应原料质量的4.2%)、反应温度为225℃、反应时间为5 h下,于反应-蒸馏工艺中可催化甘油获得转化率92.3%(质量分数)的和羟基丙酮选择性90.7%(质量分数)。Mg O修饰的海绵铜能有效地催化甘油选择性脱水至羟基丙酮。     

Ni/AC催化α-羟基丙酮加氢制1,2-丙二醇反应研究

制备了一系列Ni/AC催化剂,以α-羟基丙酮催化加氢制备1,2-丙二醇为目标反应,系统考察了Ni/AC催化剂的制备条件和反应工艺条件,结果表明催化剂的Ni负载量为15%,在550℃下煅烧4 h、H2气氛400℃还原4 h获得的催化剂为高分散的金属Ni物种,所得催化剂在质量空速1.4 h-1、反应温度280℃、α-羟基丙酮质量分数为50%的最优条件下,转化率达到了70.6%,1,2-丙二醇选择性为96.2%。     

三组分铜铬催化剂催化甘油制备羟基丙酮的研究

用共沉淀法制备了Cu-Cr-Zn催化剂,考察了Cu/Cr/Zn比、沉淀温度、沉淀时pH值、煅烧温度等制备条件对甘油制备羟基丙酮的影响,并对催化剂进行了表征。结果表明:共沉淀法制备Cu-Cr-Zn催化剂具有较高的催化活性,而且其稳定性和再生能力较好,适宜催化剂制备条件为:Cu/Cr/Zn比为1∶1∶0.5,沉淀温度为70℃,沉淀时pH值为8.0,煅烧温度为400℃,羟基丙酮的选择性可达到90.2%。     

活性炭负载铁催化剂催化羟基化甲苯制备甲酚研究

以活性炭、十二烷基磺酸铁为原料制备了活性炭负载铁催化剂,采用H_2O_2作为羟基化试剂,进行了催化羟基化甲苯制备甲酚的研究。考察了溶剂种类、催化剂用量、反应时间、反应温度及原料摩尔比对甲苯转化率和甲酚选择性的影响,试验结果表明:在溶剂为乙腈,催化剂用量为0.5 g,反应温度为30℃,甲苯与H_2O_2摩尔比为1∶5,反应时间为4 h条件下,羟基化反应后甲苯转化率为28.96%,甲酚选择性81.25%。同时结合甲苯羟基化的反应过程探讨了羟基化反应机理,为甲酚绿色催化合成工艺放大研究提供技术支撑。     

羟基新戊醛加氢合成新戊二醇催化剂及工艺研究

采用沉淀法制备了四种不同铜负载量的加氢催化剂,以氢氧化钠为沉淀剂,以碱性硅溶胶作为载体,比较了不同铜含量催化剂的活性。在固定床上考察了在不同条件下羟基新戊醛的转化率和新戊二醇的选择性,在反应压力2.5 MPa,氢醛比为10,反应温度为100℃,液时空速1.0 h-1,催化剂铜负载量为15%条件下,羟基新戊醛转化率达94%,新戊二醇选择性达99%。     

醋酸甲酯加氢制乙醇炭载铜催化剂研究

采用浸渍法制备了活性炭载Cu-Zn系催化剂,考察了制备条件对醋酸甲酯加氢反应的影响,并考察了应用条件对催化醋酸甲酯加氢反应的影响,确定了催化剂的适宜制备条件:铜锌负载量为30%、铜锌原子比为1. 0,以氢氧化钾为助剂原料,助剂加入量1. 0%,确定了该催化剂的最优应用条件:催化剂加入量2. 5%,反应温度200℃,反应压力1. 5 MPa,反应时间2 h,在此条件下进行催化合成醋酸甲酯转化率、选择性等均大于99%。5次重复使用结果表明,该催化剂的重复使用性好,具有较好的工业前景。     

用于二乙醇胺脱氢反应的铜锰系催化剂制备条件的研究

研究了铜锰系催化剂并流共沉淀法的制备条件对二乙醇胺催化脱氢反应性能的影响。结果表明，在铜锰原子比为1、溶液浓度0.4 mol·L^-1、沉淀pH为12、沉淀温度70　℃、焙烧温度550 ℃和还原温度210 ℃时，催化剂性能最好。在反应温度150 ℃和压力0.8 MPa，催化剂用量为二乙醇胺质量10%的反应条件下反应 5 h，亚氨基二乙酸盐收率可达93.2%。     

([Ni(L)_2])催化对丙烯基茴香醚氧化反应中试试验性能研究

对([Ni(L)_2])催化对丙烯基茴香醚氧化反应中试试验性能进行了研究,探讨了催化剂([Ni(L)_2])的用量、双氧水用量、反应时间及温度对中试的影响,得出最佳反应条件:催化剂([Ni(L)_2])的用量0.1 g[Ni(L)_2],140 mL30%的H_2O_2(分多次滴加),表面活性剂OP-10为0.2%,温度90℃,反应时间10 h,对丙烯基茴香醚的转化率可达89.40%。主要产物是:对甲氧基苯甲醛,其选择性为33.67%,产率为30.10%。次要产物为对羟基苯甲醚和4-甲氧基苯基丙酮,其中对羟基苯甲醚选择性为32.52%,产率为29.07%;4-甲氧基苯基丙酮选择性为14.62%,产率为13.07%。     

丙二醇甲醚气固相催化合成甲氧基丙酮

以丙二醇甲醚为原料,利用共沉淀法制备的Cu-ZnO为催化剂,在固定床反应器中催化脱氢合成甲氧基丙酮.考察了催化剂制备工艺和反应条件对催化活性的影响,并对催化剂的稳定性进行了研究.结果表明,催化剂最佳制备条件是:铜锌物质的量比为0.5,沉淀温度为55℃,55℃老化1h,采用硝酸钠改性,400℃焙烧4h.催化剂最佳反应工艺:240℃下还原4h,反应温度为250℃,液空时速为40 mL/h,氮载气速度为150 mL/min.催化剂在120 h内稳定性良好.     

纳米氧化锌催化合成松香甘油酯的研究

首次采用纳米粒子氧化锌作为松香与甘油酯化反应的催化剂,实验讨论了催化剂、反应温度、反应时间和醇酸比对反应工艺的影响,并在此基础上进行正交试验,得出反应的最佳工艺条件为:在氮气的保护下,用松香与过量20%质量分数的甘油酯化反应的反应温度为250°C、反应时间5h、催化剂0.25%(以松香量为基准)、甘油与松香的质量比为:12.19∶100。在最佳工艺条件下,进行了稳定性实验,得到的松香甘油酯的酸值为:7.3,软化点:86.9°C,产率为94.5%,色泽:加纳色级8,在苯中溶解度(1∶1):清,符合136#松香甘油酯质量指标。纳米氧化锌催化松香酯化相对目前工业常用的ZnO催化剂而言,缩短了反应时间、降低了反应温度,有应用价值。     

Selective hydrogenolysis of glycerol to propylene glycol on Cu–ZnO catalysts

Hydrogenolysis of biomass-derived glycerol is an alternative route to sustainable production of propylene glycol. Cu–ZnO catalysts were prepared by coprecipitation with a range of Cu/Zn atomic ratio (0.6–2.0) and examined in glycerol hydrogenolysis to propylene glycol at 453–513 K and 4.2 MPa H₂. These catalysts possess acid and hydrogenation sites required for bifunctional glycerol reaction pathways, most likely involving glycerol dehydration to acetol and glycidol intermediates on acidic ZnO surfaces, and their subsequent hydrogenation on Cu surfaces. Glycerol hydrogenolysis conversions and selectivities depend on Cu and ZnO particle sizes. Smaller ZnO and Cu domains led to higher conversions and propylene glycol selectivities, respectively. A high propylene glycol selectivity (83.6%), with a 94.3% combined selectivity to propylene glycol and ethylene glycol (also a valuable product) was achieved at 22.5% glycerol conversion at 473 K on Cu–ZnO (Cu/Zn = 1.0) with relatively small Cu particles. Reaction temperature effects showed that optimal temperatures (e.g. 493 K) are required for high propylene glycol selectivities, probably as a result of optimized adsorption and transformation of the reaction intermediates on the catalyst surfaces. These preliminary results provide guidance for the synthesis of more efficient Cu–ZnO catalysts and for the optimization of reaction parameters for selective glycerol hydrogenolysis to produce propylene glycol.     

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。     

CaO催化制备碳酸甘油酯

以甘油和碳酸二甲酯为原料,CaO为催化剂合成了碳酸甘油酯。通过正交实验及单因素实验,考察了反应温度、回流温度、碳酸二甲酯用量、催化剂用量、反应时间对反应的影响,确定了优化工艺条件:反应温度75℃,回流温度60℃,碳酸二甲酯与甘油摩尔比2.5∶1,催化剂质量分数0.8%(以原料总质量计,下同),反应时间2h,在该条件下,甘油转化率及碳酸甘油酯收率分别可达97.89%和96.78%。CaO的存储稳定性及重复利用性实验结果表明,CaO虽具有较佳的存储稳定性,但其重复利用性较差,使用1次后活性即显著降低。     

Kinetics of vapor-phase dehydration of glycerol into acrolein on the BAO-1 heterogeneous catalyst

The vapor-phase dehydration of glycerol on the heterogeneous catalyst 0.5B₂O₃/γ-Al₂O₃ (BAO-1) was studied. The kinetic model of the process was developed based on the data obtained in a differential reactor. To evaluate the kinetic constants of the generalized mathematical models of the kinetics of vapor-phase dehydration of glycerol, we used the differential evolution method implemented in the Mathematica 5.0 program. The calculated activation energy of the target reaction of acrolein formation was 50.18 ± 0.11 kJ/mol. The adequacy of the obtained equations was assessed using the Fisher test. The optimum conditions of the vaporphase dehydration of glycerol were determined using the proposed kinetic equations (reaction temperature 330°C, glycerol concentration in the supply stream 30%, and catalyst load 0.0338 L/(g_cat min). The obtained data may be used in calculations for large units for acrolein production by glycerol dehydration.     

A DRIFTS Study of Catalyzed Dehydration of Alcohols by Alumina-supported Heteropoly Acid

Selectively catalyzed dehydration of ethanol, 1,2-propylene glycol, and glycerol on supported heteropoly acid (HPA) was studied using transient diffuse reflectance infrared fourier transform spectroscopy (DRIFTS). Tungstosilicic acid (H₄[SiW₁₂O₄₀] denoted as H₄SiW), supported on neutral mesoporous alumina as a catalyst, was studied to investigate the formation of intermediate products and desired dehydration products on the catalyst surface. Both ethylene-containing species and surface-bound carboxyl species were detected for all three alcohols. The formation of ethylene was promoted at lower temperatures while an increased reaction temperature facilitated the formation of acetate products when ethanol was used. When 1,2-propylene glycol was used, surface-bound carboxyl species were found as major intermediate products; these might have formed from propanal produced from the hydration reaction catalyzed by acid sites on HPA. Intermediate species from more complicated reactions were detected on the catalyst surface when glycerol was used, including aldehyde, surface-bound carboxyl species, and alkene species. The results indicated that acid dehydration might be facilitated either by the addition of water or lowering the reaction temperature. The work provides insight into reaction pathways for bio-polyols, and therefore is informative for designing cost-effective and efficient chemical catalysis systems for the conversion of bio-renewables.     

甘油选择性脱水制备丙烯醛研究进展

生物柴油以其环保性和可再生性而被公认为是可替代石化柴油的新型能源,其迅猛发展将导致其副产物甘油的大量过剩,因此,开发和深度利用甘油,使其成为新一代从生物质到化学品的转化平台成为近期研究热点,其中,甘油脱水制丙烯醛是重要途径。综述了实现该过程的催化剂体系研究进展,探讨了催化剂结构和反应条件对甘油脱水反应性能的影响,分析了甘油脱水的反应路径,以期对开发高性能催化体系和合理工艺提供参考。由于匀相催化剂存在活性低、操作条件苛刻和设备腐蚀等缺点,开发的重点集中在固体酸催化剂上,虽然活性较高,但易失活,稳定性差。仍需进一步提高催化剂性能,同时结合反应器和工艺的设计和选择,综合考量。     

Kinetics of esterification of glycerol with acetic acid catalyzed by pyridine bisulfate ionic liquid

Using pyridine bisulfate ionic liquid as a catalyst, the kinetic behavior of glycerol and acetate into triacetin was systematically studied. The effects of reaction temperature, molar ratio of acid to alcohol, and amount of catalyst on glycerol conversion and triacetin yield were investigated using single factor experiments. The reaction kinetic model was developed using the quasi-homogeneous first-order reaction theory. The pre-exponential factor and the reaction activation energy were obtained by fitting the kinetic experimental data. The results showed that the conversion of glycerol increased with increasing of reaction temperature and the molar ratio of acetic acid to glycerol. With the increase of the amount of catalyst, the reaction rate of glycerol increased gradually, but the equilibrium conversion remained essentially unchanged. Under the optimum reaction conditions of temperature at 110℃, the molar ratio of acetic acid to glycerol in 6∶1 and the catalyst dosage of 3%, the maximum conversion of glycerol and the maximum yield of glycerol triacetate were 98.5% and 40.4% respectively. The pre-exponential factors k₁₀, k₂₀ and k₃₀ of glycerol with acetic acid gradually forming monoacetin, diacetin and triacetin were 7.17, 14.19 and 13.78 min^-1 respectively. The corresponding reaction activation energies E₁, E₂ and E₃ were 19.10, 21.58 and 23.25 kJ·mol^-1 respectively. The calculated values by the kinetic model were agreed well with the experimental values. The catalyst has a better catalytic effect than that of the reported Amberlyst-15 and heteropoly acid catalyst with milder reaction conditions, higher selectivity, and lower activation energy.