Die mit Natriumphenolat katalysierte Addition von Äthylenoxid-Propylenoxid-Gemischen an Monophenylmonoalkylenglykole. II. Die Kinetik der Äthylenoxid-Propylenoxid-Addition an Monophenylmonoäthylenglykol

The dependence of insertion-type addition of ethylene oxide/propylene oxide mixture to monophenyl monoethylene glycol on monomer ratios was investigated. An attempt to determine the reactivity parameters by MAYO and LEWIS method was discarded on account of differing dimensions shown by the rate constants of separate reactions. A rate law to describe the consumption of ethylene oxide has been presented. The dependence of relative reaction rates on the-mole ratios shows preference for addition of ethylene oxide; however, rise in reaction temperature exercises no appreciable effect on the preferred addition.     

Vapour phase oxidation of ethylene glycol to glyoxal on supported cupric oxide

The vapour phase oxidation of ethylene glycol to glyoxal by air was studied in a stainless steel tube reactor using cupric oxide as a catalyst on carriers such as active alumina, pumice stone, silicon carbide, ceramics and fused alumina. A catalyst containing 3 to 5% cupric oxide on pumice stone was found to be satisfactory for the process. The effects of temperature, period of reaction and concentration of ethylene glycol and oxygen on the yield and conversion to glyoxal were studied, and the most suitable conditions were determined for the process. Carbon dioxide and formaldehyde were the major by-products in the reaction. Formaldehyde was formed mainly due to the homogeneous reactions of ethylene glycol with oxygen in the void space of the reactor. The formation of glyoxal and carbon dioxide were correlated by suitable empirical rate expressions.     

Highly selective synthesis of propylene glycol ether from methanol and propylene oxide catalyzed by basic ionic liquid

BACKGROUND: Propylene glycol ether is expected to be a safe substitute for toxic ethylene glycol ether usually used in industry owing to its negligible toxicity. Although catalysis of solid acids or bases for the synthesis of the ether can avoid separation of catalysts, liquid waste treatment and corrosion problems, it suffers from drawbacks, e.g. lower activity and selectivity to target product, high reaction pressure and temperature. In order to solve these problems, a basic ionic liquid, namely choline hydroxide was prepared and used as a catalyst for synthesis of the ether via atom‐economy reaction from propylene oxide and methanol. RESULTS: The ionic liquid showed excellent catalytic performance exhibiting 95.4% conversion of propylene oxide (PO) and 94.6% selectivity to 1‐methoxy‐2‐propanol. It is also an effective catalyst for the reaction of PO with other primary alcohols to yield corresponding ethers. In addition this catalyst can be recovered and reused. CONCLUSION: The high activity and selectivity can probably be ascribed to its basicity and/or the strong polarity and electrostatic field of the reaction medium caused by the ionic liquid. These findings are very rare in synthesis of propylene glycol ether to our knowledge. Copyright © 2010 Society of Chemical Industry     

Heterogeneous photocatalytic degradation of ethylene glycol and propylene glycol

The photocatalytic decomposition of ethylene glycol and propylene glycol was investigated by using UV-illuminated TiO₂ and metal-loaded TiO₂ catalysts. The effects of pH, initial concentration, and wavelength of light on the decomposition rate of the glycols were explored. Platinum-and palladium-loaded TiO₂ catalysts enhanced the rates of photodecomposition compared to unloaded TiO₂. The glycols were oxidized primarily to carbon dioxide and water. Formaldehyde was found to be an important reaction intermediate. A detailed chemical reaction mechanism for the destruction of ethylene glycol and propylene glycol in water via free radical pathway and trapped hole reactions at the particle surface is proposed.     

镁铝复合氧化物催化合成醇醚醋酸酯的研究

介绍了以环氧乙烷、乙酸乙酯为原料,水滑石所衍生的镁铝复合氧化物作催化剂,一步合成乙二醇单乙醚醋酸酯的方法。对其反应条件进行优化,得到适宜的工艺条件:n(乙酸乙酯):n(环氧乙烷)=4:1,反应温度135℃,催化剂用量为环氧乙烷质量的4％,反应时间60min,体系初压0.9MPa,在此条件下乙二醇单乙醚醋酸酯收率为39.21％。     

废水中环氧丙烷和环氧乙烷的酸化水解预处理

采用化学酸化水解法,对废水中的环氧丙烷和环氧乙烷进行了预处理,研究了加酸量、反应温度、反应时间等因素的影响。结果表明,采用硫酸为催化剂可将废水中的环氧丙烷和环氧乙烷转化为醇类物质,反应后环烷烃质量浓度降低到100mg/L以下,提高了后继废水处理的安全性。针对该废水实际情况,得到最佳反应条件为反应温度10℃,加酸量(浓硫酸与废水体积比)1‰,反应时间12h。     

Kinetic study of olefin polymerization with a supported metallocene catalyst. II. Ethylene/1‐hexene copolymerization in gas phase

A kinetic study of ethylene/1‐hexene copolymerization is conducted with a supported metallocene catalyst in a gas‐phase reactor. The investigation into the kinetics of ethylene/1‐hexene copolymerization includes the effects of operational parameters such as the reaction temperature, pressure, and comonomer concentration. The large variations in gas‐phase composition using only an initial charge of 1‐hexene are illustrated by experiment. To remedy this, the ability to control the comonomer composition of 1‐hexene online for the entire duration of the reaction is demonstrated. Online perturbation techniques are implemented to determine key kinetic parameters such as the activation energies for propagation and catalyst deactivation. From pressure perturbation results, a reaction rate order close to 1 is obtained for ethylene in the presence of 1‐hexene. Finally, all the parameters obtained from the study are compared to those determined from ethylene–propylene (E–P) copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1096–1119, 2001     

Fe_2O_3/HZSM-5催化转化乙醇制备低碳烯烃

采用浸渍法制备了Fe2O3/HZSM-5分子筛催化剂,并用于乙醇脱水与低聚制备丙烯为主的低碳烯烃反应体系.在400～500℃范围内考察了HZSM-5的硅/铝比、氧化铁负载量、反应温度、催化剂氢气还原预处理对产物中烯烃收率的影响.结果表明,HZSM-5硅/铝比为140时,丙烯、丁烯收率最高;氧化铁负载能有效提高烯烃收率,当负载量为2.9%时丙烯收率最高,接近25%;反应初期升高温度可促进丙烯生成,但催化剂寿命缩短;氢气还原预处理能进一步促进乙烯、丙烯生成.     

Synthesis of poly(alkylene succinate) biodegradable polyesters I. Mathematical modelling of the esterification reaction

Synthesis of three biodegradable aliphatic polyesters, namely poly(ethylene succinate), poly(propylene succinate) and poly(butylene succinate) is presented using the appropriate diols and succinic acid in the presence of tetrabutoxytitanium as catalyst. A theoretical mathematical model for the esterification reaction, based on the functional group approach, is developed and applied successfully in the simulation of all experimental data. Values for the kinetic rate constants are proposed for different catalyst molar ratios and comonomer chemical structure. It was found that the presence of the metal catalyst used leads to a poor activity of self-catalyzed acid and the main kinetic rate constant of the esterification reaction correlates well with the square root of the catalyst concentration. Different glycols do not influence much the number average degree of polymerization (NADP) values of the oligomers produced, even thought they slightly affect esterification rates in the order BG>PG>EG. In contrast, these values are affected by the amount of catalyst, with larger catalyst molar ratio giving polymer with bigger average molecular weight. These results were verified from measurements of the final polyester average molecular weight obtained at different polycondensation temperatures. Finally, from theoretical simulation results it was found that although higher initial ratios of glycol to succinic acid are useful to increase the esterification rate, they lower the NADP of the oligomers formed at a fixed conversion of acid end groups.     

醇钠法合成一缩二丙二醇的工艺过程控制

介绍了一缩二丙二醇的用途及合成方法,重点阐述了以乙醇钠为催化剂,用丙二醇和环氧丙烷在一定温度和压力条件下合成一缩二丙二醇的反应原理和工艺流程,从反应温度、压力、精馏方式、催化剂回收等方面对生产工艺过程控制进行了探讨,总结出一种效率高,成本低,质量好的一缩二丙二醇的生产工艺条件。     

Polymerization of alkylene oxides with trialkylaluminum,metal acetylacetonates,and water

Trialkylaluminum and acetylacetonates of Groups II and III metals are very effective polymerization catalysts for alkylene oxides. Addition of water increased both polymerization rate and yield. Among many combinations examined, a combination of triisobutylaluminum, zinc acetylacetonate, and water is outstanding. It gives high rate, high yield, and high degree of polymerization. The mole ratio of these three components was extensively studied and shown to be less critical than for other systems. Order of addition was not important. Elastomeric products based on propylene oxide, ethylene oxide, epichlorohydrin, and allyl glycidyl ether were prepared in high yield in relatively short reaction times. Copolymerization rates for epichlorohydrin–ethylene oxide and epichlorohydrin–propylene oxide were determined and indicated that this catalyst is anionic in character. It is concluded that the bimetallic nature of this catalyst is responsible for its high reactivity, versatility and stereochemistry.     

乙二醇单己醚的合成研究

用环氧乙烷与己醇为原料合成乙二醇单己醚 ,通过正交实验得到了影响反应的 4种主要因素的大小顺序 :催化剂的量 >原料物质的量比 >反应温度 >催化剂的种类。最佳工艺条件为 :己醇与环氧乙烷的物质的量比为 :n(n C5H11CH2 OH)∶n (C2 H4 O) =1∶0 5 ;反应温度为 1 0 0℃ ;己醇与催化剂的物质的量比为 :n(n C5H11CH2 OH)∶n(催化剂 ) =1∶0 0 9。乙二醇单己醚的收率为 85 4 % ,纯度可达 98 5 %。乙二醇单己醚的纯度用气相色谱分析 ,用红外光谱、质谱对产品乙二醇单己醚的结构进行表征。     

固体碱催化剂KF/MgO催化合成丙二醇丁醚的绿色工艺研究

采用固体碱催化剂KF/MgO催化环氧丙烷(PO)和正丁醇合成丙二醇丁醚,对催化剂进行了XRD、TEM、CO₂-TPD表征,经FT-IR表征确认目标产物为丙二醇丁醚。同时对合成丙二醇丁醚的反应工艺进行了研究,优化了反应工艺。研究结果表明:适宜的工艺条件为反应温度130 ℃,催化剂用量为原料总质量的1.5%,n(丁醇)∶n(环氧丙烷)为4∶1。在此条件下,PO转化率达97.88%,丙二醇丁醚产率达81.34%。同时对催化剂使用寿命进行了考察,在重复使用4次之后,催化剂依然保持较高的活性,PO转化率达90.86%,丙二醇丁醚产率达76.13%。     

固体强碱绿色催化环氧丙烷水解合成1,2-丙二醇

该文制备了不同碱强度的固体碱催化剂,并应用于环氧丙烷(PO)水解合成1,2-丙二醇的反应。结果表明:随着催化剂碱强度的增加,环氧丙烷的转化率不断升高;说明强碱催化剂有利于环氧丙烷水解反应。在此基础上,作者系统考察了催化剂用量、反应温度、原料摩尔比和反应时间对催化性能的影响。结果表明:当催化剂CaO-ZrO2质量为反应原料质量的1.0%,反应温度为120℃,反应原料配比为:n(H2O)∶n(PO)=5∶1,反应时间2h时,其催化效果较优,环氧丙烷转化率最高为92.3%,1,2-丙二醇选择性可达89.4%。     

DMTO再生催化剂经C4/C5+裂解预积炭后对MTO反应性能的影响

采用小型固定流化床,研究了MTO副产物C4/C5^+烯烃在DMTO再生催化剂上的催化裂解反应、预积炭情况,以及预积炭后再生催化剂对MTO反应性能的影响。结果表明:C4/C5^+烯烃可作为原料在DMTO再生催化剂上进行催化裂解,生成乙烯、丙烯,增加双烯产量。在此裂解过程中,DMTO再生催化剂发生预积炭,可以提高MTO反应中双烯的初始选择性,缩短反应诱导期,提高双烯收率;同时,可以减小甲醇的生焦率,降低甲醇消耗。DMTO再生催化剂预积炭会影响催化剂寿命,其经C4/C5^+裂解预积炭过程中碳质量分数以3%左右为宜。     

不同硅铝比ZSM-5催化剂上的MTO反应性能

由于原油供应的可预见性短缺,急需开辟新的烯烃合成路线.在固定床上,以甲醇为原料、ZSM-5为催化剂,对MTO反应进行了研究,考察了反应时间、反应温度、进料水醇摩尔比以及催化剂硅铝比对甲醇制烯烃反应的影响.结果表明,反应时间对乙烯和丙烯的摩尔比有明显的影响;反应温度在一定的范围内升高可延长催化剂使用时间,但同时也使副产物增多;水醇摩尔比对乙烯加丙烯的选择性的影响不是很明显;硅铝比为38的ZSM-5催化剂上反应产物中的初始乙烯和丙烯摩尔比较高.     

Reactions of trithiocyanuric acid with oxiranes. II. Kinetics and mechanism of reactions

The study of the kinetics of the addition of trithiocyanuric acid to oxiranes (i.e., ethylene oxide and propylene oxide) in DMSO solution in the presence of triethylamine as a catalyst is described. The effects of the acid group concentration, the concentration of oxirane, and the catalyst on the course of the reaction was studied. The rate equation describing the addition was derived. The reaction order with respect to the oxirane, catalyst, and reactive groups of the acid were 0.5, 0.5, and 1.5, respectively. The mechanism of addition was proposed. The influence of temperature on the course of the reaction was also studied. The activation parameters (ΔH^#, ΔS^#, ΔG^#) were calculated. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2081–2088, 2000     

钒磷氧催化合成苯甲醛乙二醇缩醛

本文研究了钒磷氧催化苯甲醛与乙二醇的缩醛化反应 ,考察了反应时间、醛醇比、催化剂用量、带水剂用量等因素对苯甲醛乙二醇缩醛收率的影响。结果表明 ,在回流条件下 ,当苯甲醛用量为 0 .11mol,乙二醇用量为 0 .10mol,催化剂用量为 0 .0 2 5 g ,带水剂环己烷用量为 8mL ,反应 2 .5h后 ,缩醛收率可达到 71.3%。     

Reaction of ethylene oxide or propylene oxide with long-chain fatty acids. Mono- and diester formation

Summary The alkali-catalyzed reaction of ethylene oxide or propylene oxide with fatty acids was shown to be complex. Mono- and diesters were formed in comparable amounts even at an early stage when only about one equivalent of the cyclic ether had been condensed. The following compounds were isolated in a pure state: ethylene glycol monolaurate, ethylene glycol dilaurate, diethylene glycol dilaurate, ethylene glycol distearate, 1,2-propylene glycol dilaurate, and 1,2-propylene glycol distearate. A monoester from propylene oxide was shown to be a mixture of the 1-and 2-monolaurate [C₁₁H₂₃CO₂CH₂CHOHCH₃ and C₁₁H₂₃CO₂CH(CH₃)CH₂OH]. Presented at the Delaware Valley Regional Meeting, American Chemical Society, Philadelphia, February 5, 1958. Eastern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

钒磷氧非均相催化合成苯乙酮乙二醇缩酮

研究了苯乙酮与乙二醇在钒磷氧非均相催化剂作用下的缩合反应，考察了反应时间、醇酮比、催化剂用量和带水剂用量等因素对苯乙酮乙二醇缩酮收率的影响。结果表明，在回流条件下，苯乙酮为0．10mol，乙二醇为0．12mol，催化剂用量为0．20g，带水剂环己烷用量为6mL，反应2．5h后，缩酮收率可达到81．5％，且催化剂重复使用性能良好。产品经熔点仪和红外光谱仪进行了表征。