Propylene oxide production process, with flowchart included

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This post was last edited by Aggregated Cat_IEB8P on 2020-7-1 14:02. Epichlorohydrin (abbreviated as PO), also known as methyl ethylene oxide or propylene oxide, is an important intermediate in the petrochemical industry as well as a vital raw material for organic compounds. So how is propylene oxide produced? Today, we will take a brief look at the production process of propylene oxide. The outline is as follows: Brief overview and flowchart of the chlorohydrin process; Brief overview and flowchart of the ethylbenzene co-oxidation (PO/SM) process; Brief overview and flowchart of the isobutane co-oxidation (PO/MTBE) process; Brief overview and flowchart of the cumene hydroperoxide oxidation (CHP) process; Brief overview and flowchart of the hydroperoxide oxidation (HPPO) process. Introduction to the chlorohydrin process: The chlorohydrin process was first developed by UCC in the 1930s, and was later improved by Dow Chemical Company and Rumus Company in the United States. The chlorohydrin method is an early industrial production technique that has been in use for over 60 years; the key equipment in this process is the chlorohydrination reactor. The main raw materials for the chlorohydrin method are chlorine, propylene, and calcium hydroxide. Process: The main process involves preparing hypochlorous acid by mixing chlorine gas with water; propylene reacts with hypochlorous acid to yield chloropropanol, which then reacts with slaked lime (or caustic soda) to produce propylene oxide. Finally, ordinary distillation methods are used to separate the components, resulting in pure propylene oxide. https://image.juhecat.com/wp-content/uploads/2020/06/WechatIMG510.png?x-oss-process=image%2Fformat,webp Introduction to the co-oxidation of ethylbenzene (PO/SM): Since its industrialization in 1969, the co-oxidation of ethylbenzene has seen rapid development worldwide. Currently, the technology for producing PO via ethylbenzene co-oxidation is held by companies such as Shell, American Lyondell Basell, and Spanish Respol. Process: The ethylbenzene co-oxidation method uses ethylbenzene and propylene as raw materials to produce PO while simultaneously generating styrene (SM). Ethylbenzene reacts with oxygen in the air in the oxidation reactor to produce ethylbenzene peroxide and methylbenzyl alcohol ； After concentration, under the action of a catalyst, ethylbenzene peroxide reacts with propylene to produce PO and methylbenzyl alcohol; methylbenzyl alcohol then reacts under the action of a catalyst to form SM. https://image.juhecat.com/wp-content/uploads/2020/06/WechatIMG511.png?x-oss-process=image%2Fformat,webp Introduction to the isobutane co-oxidation method (PO/MTBE): The isobutane co-oxidation method was developed in 1967 by the American company ARCO. Currently, the technology for producing PO using this method is held by the American companies Lyondell Basell and Huntsman. Process: Using propylene and isobutane as raw materials, PO is produced along with the co-production of tert-butanol (TBA) or methyl tert-butyl ether (MTBE). Isobutane reacts with pure oxygen to produce tert-butyl peroxide and TBA; after concentration, tert-butyl peroxide reacts with propylene in the presence of a catalyst to yield PO and TBA, and TBA reacts with methanol to give MTBE. https://image.juhecat.com/wp-content/uploads/2020/06/WechatIMG513.png?x-oss-process=image%2Fformat,webp Introduction to the cumene peroxide oxidation process (CHP): The cumene oxidation process was developed by Sumitomo Chemical in Japan; this technology has been put into industrial use at Sumitomo Chemical’s steel plant in Chiba, Japan, as well as at the Rabigh Petrochemical Plant in Saudi Arabia. Process: The cumene oxidation method uses cumene as a carrier, and through air oxidation it is converted into cumene hydroperoxide (CHP). After concentration of CHP, it reacts with propylene in a liquid phase within a fixed-bed reactor, using a proprietary catalyst, to produce PO and dimethylbenzyl alcohol. Dimethylbenzyl alcohol is then hydrogenated to regenerate cumene for reuse. This process can be roughly divided into four steps: cumene oxidation, propylene epoxidation, removal of organic acids, and dehydration and hydrogenation of the by-product alcohol to restore it to cumene. https://image.juhecat.com/wp-content/uploads/2020/06/WechatIMG514.png?x-oss-process=image%2Fformat,webp Introduction to the peroxide oxidation process (HPPO): At present, the HPPO process technologies developed by Dow/BASF and Degussa/UhdeF are the most mature and have been put into industrial use. It was not until 2014 that the international oligopoly situation was broken, as the HPPO process developed independently by Sinopec Hunan Changling (100,000 tons) came online for operation; simultaneously, the HPPO project developed independently by Jilin Shenhua (300,000 tons) also began operations. Process: Hydrogen peroxide oxidation method (HPPO) – using TS-1 as a catalyst, hydrogen peroxide as an oxidant, and methanol as a solvent, to directly oxidize propylene into PO under medium-temperature and low-pressure liquid-phase conditions. https://image.juhecat.com/wp-content/uploads/2020/06/WechatIMG515.png?x-oss-process=image%2Fformat,webp