Propylene oxide, manufacture

There have been a number of cell designs tested for this reaction. Undivided cells using sodium bromide electrolyte have been tried (see, for example. Ref. 29). These have had electrode shapes for in-ceU propylene absorption into the electrolyte. The chief advantages of the electrochemical route to propylene oxide are elimination of the need for chlorine and lime, as well as avoidance of calcium chloride disposal (see Calcium compounds, calcium CHLORIDE Lime and limestone). An indirect electrochemical approach meeting these same objectives employs the chlorine produced at the anode of a membrane cell for preparing the propylene chlorohydrin external to the electrolysis system. The caustic made at the cathode is used to convert the chlorohydrin to propylene oxide, reforming a NaCl solution which is recycled. Attractive economics are claimed for this combined chlor-alkali electrolysis and propylene oxide manufacture (135). 

Chlorohydantoin moiety, 73 113 Chlorohydrin, 72 649—650 Chlorohydrination, in the chlorohydrin process, 20 799-800 Chlorohydrin processes, 70 655 24 172 for propylene oxide manufacture, 20 796, 798-801... 

Hydronium ion, 14 23 Hydroperoxidates, 18 411 Hydroperoxide process, for propylene oxide manufacture, 20 798, 801-806 Hydroperoxides, 14 281, 290-291 18 427-436 alkylation of, 18 445 a-oxygen-substituted, 18 448-460 chemical properties of, 18 430 433 decomposition of, 14 279 18 431-432 liquid-phase epoxidation with, 10 656 physical properties of, 18 427-430 preparation by autoxidation, 18 434 synthesis of, 18 433-435 Hydrophile-lipophile balance system,... 

Tubular reactors are also used to carry out some multiphase reactions. Wamecke et al. (1999) reported use of a computational flow model to simulate an industrial tubular reactor carrying out a gas-liquid reaction (propylene oxide manufacturing process). In this process, liquid is a dispersed phase and gas is a continuous phase. The two-fluid model discussed earlier may be used to carry out simulations of gas-liquid flow through a tubular reactor. Warnecke et al. (1999) applied such a model to evaluate the influence of bends etc. on flow distribution and reactor performance. The model may be used to evolve better reactor configurations. In many tubular reactors, static mixers are employed to enhance mixing and other transport processes. Computational flow models can also make significant contributions to understanding the role of static mixers and for their optimization. Visser et al. (1999) reported CFD... 

M. Ishino, J. Yamamoto, Propylene oxide manufacturing processes, Shokubai 48 (2006) 511-515. 

Industrial Processes for Propylene Oxide Manufacture Present and Future... 

INDUSTRIAL PROCESSES FOR PROPYLENE OXIDE MANUFACTURE PRESENT AND FUTURE... 

Methyl terf-butyl ether (MTBE) is an important industrial product used as oxygenate additive in reformulated gasoline. Environmental concern makes its future uncertain, however. Although mainly manufactured by reaction of isobutylene with methanol, it is also produced commercially from methanol and fcrr-butyl alcohol, a by-product of propylene oxide manufacture. Numerous observations from the use of heteropoly acids have been reported. These compounds were used either as neat acids [74], or supported on oxides [75], silica or K-10 montmorillonite [76]. They were also used in silica-included form [77] and as acidic cesium salts [74,77]. Other catalysts studied were sulfated ZrOj [76], Amberlyst 15 ion-exchange resin [76], HZSM-5 [76], HF-treated montmorillonite, and commercial mineral acid-activated clays [75]. Hydrogen fluoride-treatment of montmorillonite has been shown to furnish particularly active and stable acid sites thereby ensuring high MTBE selectivity (up to 94% at 413 K) [75]. 

Table 1.10 List of processes for propylene oxide manufacture with metal framework-containing zeotype or other porous materials as catalysts...

Most -butanol is now obtained as a co-product of Arco s propylene oxide manufacture (section 12.8.2). In addition to minor speciality uses, some is used directly in gasoline, but most is dehydrated to isobutene for conversion into MTBE (methyl -butyl ether), a preferred octane improver in reformulated (lead-free) gasoline. 

If large amounts of isobutyl alcohol are available as by-product of the Oxirane process for propylene oxide manufacture, it can also be obtained very easily form the isobutylene contained in Cl streams of steam cracking units. After the recovery of butadiene, the isobutylene of these streams is selectively hydrated to tertiary butyl alcohol. This process carried out in the liquid phase in the presence of a solid catalyst is certainly realized in fixed bed reactors. Very few details have been disclosed on this reaction which constitutes the first step of a new process to obtain methylmethacrylate from a spent butylene isobutylene feed (5 ). 

Isopropanol is used in the production of other chemicals such as derivative ketones, isopropylamines, and isopropyl esters. The use of isopropanol in the production of monoisopropylamine for herbicides (primarily glyphosate) continues to be the fastest growing segment (Anonymous 2001b). A minor use for isopropanol is to serve as a feedstock for the production of acetone to meet the demand in excess of the coproduct acetone from phenol production. However, isopropanol is also produced from crude acetone, which is generated as a by-product of propylene oxide manufacture (Anonymous 2001b). 

The molecule C3H6O is propylene oxide, an important raw material in the manufacture of unsaturated polyesters, such as those used for boat bodies, and in the manufacture of polyurethanes, such as the foam in automobile seats. Reaction (1-A) describes the stoichiometry of the chlorohydrin process for propylene oxide manufacture. This process is used for about one-half of the worldwide production of propylene oxide. 

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