过氧化氢与环氧丙烷生产的集成工艺

从电解法、蒽醌法、醇氧化法、氢氧直接化合法等方面评述了制备过氧化氢的现状。介绍了过氧化氢和环氧丙烷生产的集成技术,包括蒽醌法或醇氧化法生产过氧化氢与丙烯环氧化制环氧丙烷的集成工艺以及氢气、氧气、丙烯原位合成环氧丙烷工艺。指出氢气、氧气、丙烯原位合成环氧丙烷工艺是最具前景的合成方法,但该方法的环氧丙烷收率较低,而改善催化剂合成技术是此方法实现工业化的关键。     

过氧化氢环氧化丙烯制环氧丙烷的研究新进展

综述了过氧化氢与丙烯环氧化反应的研究新进展,主要包括商品过氧化氢与丙烯环氧化、过氧化氢制备与丙烯环氧化的集成、氢氧原位一步法丙烯环氧化的研究.并分析了我国环氧丙烷生产面临的挑战,指出我国环氧丙烷清洁生产势在必行,国内研究应立足环境友好新工艺,关键是高活性、高选择性催化剂的开发.     

环氧丙烷绿色合成技术进展

环氧丙烷 (PO)绿色合成的研究主要集中在催化剂的选取和实验条件的优化上。文章综述了近几年在PO绿色合成方面的研究方法 ,包括光助催化氧化丙烯合成PO、Ag催化剂催化丙烯环氧化、Au催化剂催化丙烯环氧化、TS - 1催化剂合成PO等技术 ,并对其前景进行了分析展望。     

国外用过氧化氢环氧化丙烯制环氧丙烷研发近况

介绍了国外用过氧化氢环氧化丙烯制备环氧丙烷（PO）工艺技术近期研发概况,内容包括所用过氧化氢来源（来自蒽醌法或氢、氧直接化合法）、丙烯环氧化反应以及反应产物精制和原料回收循环利用过程,工艺涉及催化剂、溶剂、流程、反应器、操作方法和试验结果等。不少工艺是将过氧化氢合成与丙烯环氧化加以耦合,形成完整体系,提高运转效率和经济效益。此外,简略介绍了用过氧化氢制PO工艺在产业化方面的最新进展。     

用异丙苯过氧化氢作氧化剂合成环氧丙烷的新技术(待续)

介绍了环氧丙烷的用途及国内外合成技术和经济概况。详细介绍了住友化学公司的以异丙苯过氧化氢作氧化剂合成环氧丙烷的工艺,该工艺包括异丙苯氧化、丙烯环氧化、丙烯和环氧丙烷回收与精制、二甲基苄醇脱水与氢化以及有害杂质去除等步骤,整个工艺无联产品生成,装置建设费用比传统的Halcon法工艺约低1/3。     

Au基、Ag基催化剂上丙烯环氧化制备环氧丙烷的研究进展

丙烯直接氧气环氧化制环氧丙烷是催化领域最关键的挑战之一,被誉为工业界的"圣杯"。文章对近年来开展的以氧气为氧化剂的Au基、Ag基催化剂上丙烯环氧化制备环氧丙烷的研究结果进行了综述,并对其前景和发展方向进行了分析展望。     

氯丙烯直接环氧化合成环氧氯丙烷技术研究进展

环氧氯丙烷是一种重要的有机化工原料和中间体,工业化生产环氧氯丙烷的方法主要有丙烯高温氯化法、乙酸丙烯酯法和甘油法,氯丙烯直接环氧化法合成环氧氯丙烷是一种绿色清洁、原子经济性高的新工艺。综述了近年来以H₂O₂、叔丁基过氧化氢为氧化剂的氯丙烯直接环氧化合成环氧氯丙烷的催化体系的研究进展,主要包括钛硅分子筛、杂多酸盐、配合物等催化剂制备、溶剂选择和催化机理,并对氯丙烯直接环氧化法催化剂未来可能的发展方向进行了展望。     

天津建丙烯环氧化制环氧丙烷中试装置

天津市科技创新专项基金重点扶持项目——1500t．a^-1丙烯直接环氧化制环氧丙烷项目中试装置日前建成。该装置采用自主开发的丙烯直接环氧化新型催化工艺，实现了工艺过程的环保和节能减排。     

钛硅分子筛催化丙烯环氧化工艺研究

以钛硅分子筛TS-2为催化剂,过氧化氢为氧化剂,甲醇为溶剂,研究TS-2催化剂催化丙烯生成环氧丙烷.考察了停留时间、反应温度、反应压力和催化剂用量对环氧丙烷收率和选择性的影响.实验结果表明,合适的反应条件为50℃,0.30 MPa,催化剂用量为反应物质量的3.44%,停留时间90 min.在该条件下反应,过氧化氢的平均转化率和环氧丙烷的选择性分别为45%和96%左右.TS-2催化剂的重复使用实验表明,TS-2催化剂在催化丙烯环氧化制环氧丙烷的反应中具有较好的催化活性和稳定性.     

环氧丙烷生产技术现状及进展

对环氧丙烷生产技术的现状及新动向进行了综述，提出以Ｓｉ－Ｔｉ分子筛为催化剂的丙烯直接环氧化法是今后发展的方向。     

环氧丙烷合成技术的研究进展及展望

介绍了丙烯氧化制环氧丙烷的催化工艺和催化剂的研究现状,包括现有环氧丙烷的生产工艺,分子氧为氧化剂、过氧化氢为氧化剂、O2／H2为氧化剂、有机过氧化物为氧化剂的丙烯直接环氧化以及光催化氧化等;并对各反应工艺和催化剂、催化反应机理和发展前景进行了讨论。     

环氧丙烷生产工艺进展

综述了近年来环氧丙烷合成工艺的新进展,包括对现有环氧丙烷生产工艺的革新、直接氧化法、光催化环氧化等方法,并对各种方法的特点和发展前景进行了讨论.     

环氧丙烷生产工艺述评及发展设想

介绍国内环氧丙烷生产概况和氯醇法、联产法及过氧化氢直接氧化丙烯制环氧丙烷工艺,以及近期国内外环氧丙烷生产工艺研发情况。并对比3种生产工艺,提出对国内环氧丙烷改造和发展的意见。     

丙烯氢氧环氧化动力学与反应器概念设计研究进展

环氧丙烷（PO）在全球产能最高的35种化学品中,是仅次于聚丙烯的第二大丙烯衍生物,主要用于生产聚醚多元醇、聚氨酯等。相比传统的氯醇法、共氧化法和双氧水直接氧化法（HPPO）等PO生产工艺,丙烯在氢氧混合气中一步环氧化制PO（HOPO）具有工艺简单、选择性高、产物易分离、能耗低等突出优势,是生产PO的理想工艺。重点介绍了丙烯氢氧环氧化反应动力学研究进展,包括主、副反应动力学模型以及催化剂失活模型。总结了基于该过程安全操作的反应器概念设计进展。分析了丙烯氢氧环氧化反应存在的挑战,从副产物生成途径、失活动力学及颗粒催化剂上的动力学等方面展望了可能的研究方向。     

Direct Oxidation of Propylene to Propylene Oxide with Molecular Oxygen: A Review

The direct oxidation of propylene to propylene oxide (PO) using molecular oxygen has many advantages over existing chlorohydrin and hydroperoxide process, which produce side products and require complex purification schemes. Recent advances in liquid-phase and gas-phase catalytic oxidation of propylene in the presence of only molecular oxygen as oxidant and in absence of reducing agents are summarized. Liquid-phase PO processes involving soluble or insoluble Mo, W, or V catalysts have been reported which provide moderate conversions and selectivities, but these likely involve autoxidation by homogeneous chain reactions. Gas-phase PO catalysts have been mostly Ag-, Cu-, or TiO₂-based substances, although other compositions such as Au-, MoO₃-, Bi-based catalysts and photocatalysts have also been suggested as possibilities. The Ag catalysts differ from those used for ethylene oxide production in having high Ag contents and numerous additives. The additives are solid-phase alkali metals, alkaline earth metals, and halogens, with the most common substances being NaCl and CaCO₃. Nitrogen oxides in the form of gas-phase species or nitrates have also been found to be effective in enhancing PO production. Direct epoxidation by surface nitrates is a possibility. Titania catalysts supported on silicates have also been reported. These have higher PO selectivities at high conversion than silver catalysts.     

Epoxidation of Propylene over Ag-CuCl Catalysts Using Air as the Oxidant

Ag-CuCl catalysts were found to be active and selective for the epoxidation of propylene using air as the oxidant. Ag catalyst gives a propylene conversion of 31.6%, with a propylene oxide (PO) selectivity of 0.42% at a reaction temperature of 350 °C after 220 min of reaction. Addition of CuCl significantly improves the selectivity to PO, and suppresses the conversion of propylene. The Ag-CuCl (1/0.6) catalyst gives propylene conversion of about 3% and a PO selectivity of about 30% at a reaction temperature of 350 °C after 500 min of reaction. The activity of the Ag-CuCl catalyst increases with the reaction time and the selectivity to PO is very stable for this catalyst. It is found that AgCl and CuO phases formed during the catalyst preparation are beneficial to the epoxidation of propylene.     

Selective propylene epoxidation in liquid phase using highly dispersed Nb catalysts incorporated in mesoporous silicates

Selective propylene epoxidation to propylene oxide(PO) with hydrogen peroxide(H_2O_2) was carried out in a catalytic semi-batch reactor.High propylene epoxidation activity(44 h~(-1)) was observed over Nb based mesoporous silicate materials Nb-TUD-1 under mild operating conditions.The physical and chemical properties of the Nb based silicates characterized using BET,FTIR,TPD,TEM and UV–Vis revealed that the site isolation and surface acidity are crucial for PO production.Catalyst synthesis methods were investigated for their effects on PO productivity,PO selectivity and H_2O_2 utilization efficiency.It is found that Nb-TUD-1 material synthesized by the sol–gel method is more active and selective than impregnated materials for liquid phase propylene epoxidation.Surface characterization confirms that thus synthesized Nb-TUD-1 catalysts have more Lewis acidity and less Bronsted acidity compared to the catalysts by impregnation.     

Reactions of Propylene Oxide on Supported Silver Catalysts: Insights into Pathways Limiting Epoxidation Selectivity

The reactions of propylene oxide (PO) on silver catalysts were studied to understand the network of parallel and sequential reactions that may limit the selectivity of propylene epoxidation by these catalysts. The products of the anaerobic reaction of PO on Ag/??-Al₂O₃ were propanal, acetone and allyl alcohol for PO conversions below 2?C3%. As the conversion of PO was increased either by increasing the temperature or the contact time, acrolein was formed at the expense of propanal, indicating that acrolein is a secondary reaction product in PO decomposition. With addition of oxygen to the feedstream the conversion of PO increased moderately. In contrast to the experiments in absence of oxygen, CO₂ was a significant product while the selectivity to propanal decreased as soon as oxygen was introduced in the system. Allyl alcohol disappeared completely from the product stream in the presence of oxygen, reacting to form acrolein and CO₂. The product distribution may be explained by a network of reactions involving two types of oxametallacycles formed by ring opening of PO: one with the oxygen bonded to C1 (OMC1, linear) and the other with oxygen bonded to C2 (OMC2, branched). OMC1 reacts to form PO, propanal, and allyl alcohol. OMC2 can give rise to acetone and PO. (DFT) calculations have verified accessibility to the two oxametallacycle structures from propylene and PO, and have provided energy barriers for each of the steps involved in PO isomerization. This work illustrates the complex manifold of sequential reactions that contribute to the difficulty of achieving high selectivity in direct propylene epoxidation with silver catalysts.