环氧丙烷绿色制造新技术综述

环氧丙烷（PO）是一种重要的基础化工原料，主要用于生产聚氨酯、不饱和树脂和表面活性剂等。氯醇法和共氧化法（Halcon法）是目前工业生产PO的主要方法。这两种方法占世界总生产能力的99％以上，其中共氧化法超过60％左右。     

过醋法生产环氧丙烷

环氧丙烷(以下简称PO)是一种重要的基本有机原料,近年来已上升为主要石油化工二次产品之一。当前工业上生产PO的方法,有古老的氯醇法以及六十年代末七十年代初研究成功的哈康(Halcon)法和过醋酸法。众所周知,氯醇法技术成熟,PO收率达80-90％;但每吨PO需耗用l.4吨氯气,其生产规模受氯碱工业牵制;每生产1吨PO,副产的含氯化钙水溶液达40吨之多,造成环境污染严重。哈康法按所用的氢过氧化物的不同,分为乙基苯哈康法和异丁烷哈康法两个衍生工艺。该法PO收率,选择     

苯氧菌胺的合成

[目的]研究并改进了水稻田杀菌剂苯氧菌胺的合成路线。[方法]以邻氯苯甲酸为起始原料,经醚化、氯化、氰化、醇解(Pinner法)、缩合、胺解等6步反应得到苯氧菌胺。[结果]通过对反应条件进行控制和优化,苯氧菌胺的总收率为27.02%,重结晶后纯度为99.6%。[结论]该合成路线条件成熟、可靠、简便可行,可以规模化应用。     

3-和4-氧代-紫罗兰醇糖苷的合成研究进展

3-和4-氧代紫罗兰醇糖苷是一种糖苷类香料前体,用经典的Koenigs-Knorr法,溴代乙酰糖分别与3-氧代-α-紫罗兰醇和4-氧代-β-紫罗兰醇反应可得到3-氧代-α-紫罗兰醇糖苷和4-氧代-β-紫罗兰醇糖苷。详细地说明了3-氧代-α-紫罗兰醇和4-氧代-β-紫罗兰醇的各种合成方法,综述了香料前体3-氧代-α-紫罗兰醇糖苷和4-氧代-β-紫罗兰醇糖苷的合成研究进展。     

电导法用于氯醇橡胶热氧降解的研究

电导测量法用于氯醇橡胶热氧降解的研究,可以连续和直观地显示HCl释出反应的过程。测得二元共聚生胶热氧降解反应的表现速率常数k表=1.15×10~(-6)秒~(-1),表现反应活化能E表=12千卡/克分子。考察了铅丹、碱土金属氧化物和碳酸盐等添加剂的作用。探讨了氯醇橡胶热氧降解的机理。     

丙烯环氧化生产环氧丙烷新方法

环氧丙烷是重要的基础化工原料，主要用于生产聚氨酯、不饱和树脂和表面活性剂等，市场需求不断增加。目前全世界的产量为450万吨／年，我国的产量约为30万吨／年。然而，工业上现有生产环氧丙烷的两种主要方法——氯醇法和Halcon法，分别存在设备腐蚀、环境污染和产生大量联产品等问题。因此，近年来科学家和世界各大生产厂商都在积极寻找环境友好、无联产品及成本低的新方法。     

丙烯环氯化生产环氧丙烷新方法

环氧丙烷是重要的基础化工原料，主要用于生产聚氨酯、不饱和树脂和表面活性剂等，市场需求不断增加。目前全世界的产量为450万吨／年，我国的产量约为30万吨／年。然而，工业上现有生产环氧丙烷的两种主要方法——氯醇法和Halcon法，分别存在设备腐蚀、环境污染和产生大量联产品等问题。因此，近年来科学家和世界各大生产厂商都在积极寻找环境友好、无联产品及成本低的新方法。     

氯氟吡氧乙酸十二酯的合成及生物活性测定

为延长氯氟吡氧乙酸在土壤中的持效期,以五氯吡啶、十二醇为起始原料,采用活性亚结构拼接方法,合成了氯氟吡氧乙酸十二酯,应用氢核磁共振、碳核磁共振、氟核磁共振、红外和质谱验证了所合成化合物结构.生物活性测试结果表明:20%(质量分数)氯氟吡氧乙酸十二酯乳油对休闲地婆婆纳、猪殃殃和一年蓬等阔叶杂草具有优良的防除效果,150 g a.i./hm2处理对休闲地阔叶杂草的总草平均株防效为92.0%.     

氧氯化反应及其在氯乙烯生产中的应用

一、前言氧氯化反应是指有催化剂存在下,以氯化氢和氧的混合物为氯源进行氯化的反应。这一反应最早发源于古典的氯气生产法即所谓Deacon法。这一方法,就是用氯化铜为催化剂,使氯化氢与氧反应,生成氯气:     

氯氧镁水泥的研究进展

本文综述了氯氧镁水泥的研究进展,介绍了氯氧镁水泥的各种优异的性能、缺陷和相变机理,总结了氯氧镁水泥的改性方法及其制品的开发利用的情况。     

Increasing the low propene epoxidation product yield of gold/titania-based catalysts

One of problems connected with the use of gold/titania-based catalyst systems is the low yield in propene oxide (up to 2 wt.%). It is shown that the low propene oxide yield is due to product inhibition. New catalysts and process options for propene epoxidation with hydrogen and oxygen are discussed.     

Switching off propene hydrogenation in the direct epoxidation of propene over gold–titania catalysts

Low gold-loaded gold–titanium catalysts with very small gold nanoparticles for the direct epoxidation of propene have a remarkably high epoxidation activity. A disadvantage, however, is that these catalysts in certain cases also have a very high activity for the unwanted hydrogenation of propene to propane. The addition of a small amount of carbon monoxide to the feed gas can completely switch off this propene hydrogenation, while at the same time also reducing the rate of direct water formation. The co-ordination environment of titanium plays an important role in propene hydrogenation.     

高性能钛硅分子筛可控合成及其催化丙烯气相环氧化研究进展

随着绿色化工发展战略的推进,钛硅分子筛凭借其独特的选择性环氧化能力而引起广泛关注,合理调控钛硅分子筛的结构是提升烯烃环氧化反应效果的关键。本文分别对钛硅分子筛的结构类型、硅钛原子比、表面疏水性、颗粒传质性能的调控方法进行了介绍,系统总结了高活性钛硅分子筛的合成策略,并概述了TS-1钛硅分子筛工业生产技术的进展。以负载金属的钛硅分子筛催化剂为例,着重讨论了基于该催化剂的丙烯直接临氢气相环氧化反应的性能与机理,肯定了催化剂中包括载体钛位点和负载金属位点的双位点在环氧化反应中的重要性,并从金基催化剂的电子性质、空间分布、尺寸效应三个方面总结了高效金属位点的调控策略。此外,基于丙烯气相临氢环氧化当前存在的问题与挑战,进一步提出其潜在的解决方案与未来的发展方向。     

Synthesis of cyclic carbonates from epoxides: Use of reticular oxygen of Al2O3 or Al2O3-supported CeOx for the selective epoxidation of propene

Reticular oxygen of Al₂O₃ or CeO_x supported on Al₂O₃ was used for the epoxidation of propene without any double bond cleavage. In batch reaction, Al₂O₃ alone was able to convert propene into propene oxide (PO) with 100% selectivity and 2% conversion of propene with a close to 3:1 ratio with respect to the number of Al(III) reduced to elemental Al. When Ce₂O₃/Al₂O₃ or CeO₂/Al₂O₃ was used, Al remained in its +3 oxidation state, while the Ce oxide was the oxidant as demonstrated by XPS analyses. CeO_x/Al₂O₃ was more active (propene conversion yield of 4–5%) but the selectivity was lower (70%) as PO was isomerized into acetone and propionaldehyde.

Interestingly the use of reticular oxygen very much improves the selectivity with respect to the use of pure O₂. In fact, while propene was more efficiently oxidized (10%) with O₂ in presence of Al₂O₃ or CeO_x/Al₂O₃, the selectivity was as low as 40% because C1 and C2 products were formed. However, the use of reticular oxygen represents a selective two-step technique for the use of molecular oxygen as oxidant of propene. The used oxides can be re-oxidized and the whole process can be further improved towards higher yields.

PO is quantitatively converted into propene carbonate by reaction with CO₂ in presence of Nb₂O₅.     

Vapor-Phase Epoxidation of Propene over Au/Ti-MCM-41 Catalysts: Influence of Ti Content and Au Content

Ti-MCM-41 samples were used for propene epoxidation using H₂ and O₂ after Au deposition by deposition--precipitation. Au nanoparticles supported on Ti-MCM-41 with Ti incorporated hydrothermally followed by post-synthesis grafting gave higher propene oxide yields than Ti-MCM-41 with Ti incorporated hydrothermally or by grafting. Au L₃-edge EXAFS spectra show the presence of metallic Au for the low Au content (0.21 wt%) catalyst which is more selective to epoxidation, while at high Au loadings (0.42 wt%) oxidic Au species are observed and the catalyst shows lower epoxide selectivity.     

苯乙烯分子氧环氧化多相催化剂研究进展

针对近年来国内外苯乙烯分子氧环氧化多相催化剂的研究进展进行了综述,主要介绍了钴系、金系、铁系及其他催化体系等催化剂。其中,钴系催化剂活性高,工艺条件温和,绿色环保,但价格昂贵;金系催化剂在低温条件下对苯乙烯分子氧环氧化表现出良好的活性;铁系催化剂活性低,但经济性好。指出负载型钴系、金系催化剂在苯乙烯分子氧环氧化研究中有潜在的应用前景。     

原料中杂质对丙烯与苯烷基化催化剂性能的影响

分析了原料中杂质对催化剂活性和稳定性的影响及脱除杂质的方法。不同来源的丙烯所含杂质不同 ,炼厂丙烯杂质主要是氮化物和双烯 ,而裂解丙烯杂质主要是双烯 ;苯的主要杂质是饱和烷烃和微量水 ,这些杂质对催化剂活性和稳定性都有影响。实验结果表明 ,杂质含量越高 ,催化剂的活性和稳定性越低 ,而采用强酸性阳离子交换树脂可以脱除丙烯中的杂质。     

催化分子氧环氧化环己烯的研究进展

介绍了分子氧的构型、催化烯烃环氧化机理及其催化环氧化环己烯的研究进展,提出以分子氧为氧源,催化环氧化环己烯的关键在于高效催化剂的制备及廉价易得还原剂的筛选。     

Catalytic vapour phase epoxidation of propene with nitrous oxide as an oxidant II. Development of a kinetic model

The vapour phase epoxidation of propene with nitrous oxide (N₂O) was experimentally investigated in a fixed bed reactor using a CsO_x/FeO_y/SiO₂ catalyst over a broad range of residence times. The influence of feed composition on the conversion and product distribution was determined for the reactants propene, propylene oxide (PO), propionaldehyde (PA), and N₂O. The experimental results were used to derive a formal kinetic model to describe the reactions in a network deduced in the first part of this publication [Thömmes, T., Zürcher, S., Wix, A., Reitzmann, A., Kraushaar-Czarnetzki, B., 2007. Catalytic vapour phase epoxidation of propene with nitrous oxide as an oxidant: I. Reaction network and product distribution. Applied Catalysis A 318, 160-169]. Self-inhibition of the propene conversion was observed, and an inhibition of the PO conversion through PO isomerisation products. The N₂O concentration has almost no effect on the conversion of propene and PO, but the PA conversion is accelerated significantly through N₂O. Propene related and N₂O related PO selectivities display opposed dependencies from reactant concentration. The modelling results indicate that coke is predominantly formed from oxygenated products. It is the key issue for future developments to prevent the fast consecutive conversion of PO.     

Bi2SiO5/SiO2的合成及催化丙烯气相环氧化反应

水热法合成了具有介孔特征的系列Bi2SiO5/SiO2催化剂（记为SBn,n为Si与Bi物质的量比,n=0.5、5、10、20、50）,并通过X射线粉末衍射、N2物理吸附-脱附和扫描电镜等技术对SBn催化剂进行表征。结果表明,以O2为氧源,SBn催化剂在气相丙烯环氧化反应中具有良好的催化活性。在温度330 ℃,SB20催化剂上环氧丙烷选择性达50%,对应丙烯转化率为0.6%;而在温度470 ℃时,SB20催化剂上丙烯转化率接近20%,但环氧丙烷选择性降至20%。