Development of New Propylene Oxide Process - …

1 1 sumitomo KAGAKU 2006-IIntroductionPropylene Oxide (PO) is a major industrial productwith production of more than 6 million tons per yearworldwide. Approximately 70% of it is used aspolypropylene glycol in the raw materials for urethane,and the remainder is used as Propylene glycol in theraw materials for unsaturated polyesters, food productadditives and cosmetics (Fig. 1). The demand for ure-thane is growing remarkably, particularly in Asia, andone PO producer after another is announcing businessplans for new plants (Fig. 2). Production by the princi-ple producers of PO worldwide is shown in Fig. 3, andFig. 4shows the proportions of production by produc-tion production methods that have been industrial-ized up to this point can be roughly divided into twomethodologies.

2 The first is PO-only production meth-ods using chlorine, and the other is co-productionmethods that produce co-products such as styrenemonomers along with the PO. All of the industrialprocesses that have been implemented up to now carryDevelopment of New PropyleneOxide ProcessThere has always been a strong demand for the Development of a new PO-only Process . Conventionalprocesses the chlorohydrin PO-only Process and the organic hydroperoxide Process , which generates a hugeamount of co-products have given PO producers headaches due to the generation of waste that is not envi-ronmentally friendly and the dependence of product price on the fluctuating market for the Development of a high performance titanium epoxidation catalyst by our researchers, we have suc-ceeded in establishing a novel PO-only manufacturing Process where cumene acts as the oxygen new PO Cumene Process is considered a green Process since it gives higher yields than conventionalprocesses while only producing small amounts of Chemical Co.

3 , & Coordination Office, Petrochemicals & Plastics SectorJunpei TSUJIP etrochemicals Research LaboratoryJun YAMAMOTOM asaru ISHINOR abigh Project OfficeNoriaki OKUFig. 1 Uses for Propylene Oxide (PO)Unsaturated polyester resins building materialsIndustrial use antifreeze, lubricantPharmaceuticals toothpaste, cosmeticsPropylene glycolPolyurethane (rigid forms) refrigerator, insulatorPolyurethane (flexible forms) car seat, mattress, carpetNon forms elastomer, adhesive, paintPolyolsFig. 2 Asian PO demand forecasting (excluding Japan)02004006008001,0001,2001,4001,6001 ,80020032004200520062007200820092010(100 0T/y)This paper is translated from R&D Report, sumitomo KAGAKU , vol. KAGAKU 2006-IDevelopment of New Propylene Oxide Processwith them the problem of byproducts and the problemof controlling market conditions and the like for the co-products, and the PO producers in various countrieshave been focusing the attention on developing a newPO-only Chemical has also been eagerly research-ing new PO-only production methods.

4 Taking theopportunity of our successfully developing a new epoxi-dation catalyst in 1998, we were successful in establish-ing the technology for a new PO production Process ,and starting in 2003, we began using the new PO-onlyproduction method at 150,000 tons per year at ourChiba Plant. After this, we implemented a plantenhancement to 200,000 tons per year in the fall of2005 based on the healthy demand in Asia, and opera-tions are continuing to go well. Furthermore, we planto start operating a second plant (200,000 tons of POper year) in 2008 according to the Rabigh plan forSaudi with reviewing the current industrial Process -es, this paper introduces the features of the PO-onlyprocess developed by sumitomo PO Production ProcessesThe Propylene Oxide (PO) production processes thathave been industrialized so far can be roughly dividedinto the chlorine method, which is a PO-only method,and the organic peroxide method, which is a co-pro-duction method.

5 Each of these production methods willbe introduced in the ), 2)1. Chlorine MethodThe chlorine method (also known as the chlorohy-drin method) is technology that was originally used forthe production of ethylene Oxide , but in the 1960s, withthe conversion of production methods to direct oxida-tion methods for ethylene Oxide , it became the methodused for producing PO using the idle plants. Thelargest producer using this method is the Dow Chemi-cal Company, and there are two Japanese producers,Asahi Glass Co. Ltd. and Tokuyama Corp. Up to now,this was the only industrial PO-only and chlorine are reacted to produce a mix-ture of - and -chlorohydrin (9:1), and next, PO is syn-thesized by reaction with an alkali (calcium hydroxide,for example).

6 The only product is PO, and as a byprod-uct, an alkali salt is produced in the same molar quanti-ty as the PO. This production method is a moderatetemperature reaction in an aqueous solution, but foreach ton of PO, a large amount of secondary raw mate-rials, tons of chlorine and one ton of calciumhydroxide, are necessary, and approximately tonsof calcium chloride is produced as a byproduct. In addi-tion, a large excess of water is present in this reaction,and a chlorohydrin concentration of 3 6% is main-tained, so the formation of chlorine adducts must becontrolled. Therefore, a large volume of waste watercontaining the alkali salt is produced (a volume severaltens of times that of the PO), and the Process is onewith an extremely large waste water Organic Peroxide MethodThe organic peroxide method (also known as thehydroperoxide method) was first developed by HalconCorp.

7 And Atlantic Richfield Oil Corp. (later ARCO) inthe 1970s. In this method there is a method using eth-ylbenzene and a method using isobutane, and in eachof them PO is synthesized by indirect epoxidation ofFig. 3 Global PO supplier and capacity (1000t/y)Total 6740kt/y(2003. Estimated)Dow2300 Lyondell(incl. Bayer)1860 sumitomo + Nihon oxirane380 Repsol 250 OthersHuntsman 230 Shell/BASF 900 Fig. 4PO production technologiesChlorohydrin(45%)Dow Asahi Glass TokuyamaPO/SM(35%)Lyondell Shell Repsol Nihon Oxirane SKC ChemicalPO/TBA(20%) Lyondell HuntsmanPO-only production methodCo-production methodSumitomo New PO process2CH3CH = CH2 + 2 HOClCH3 CHCH2Cl + CH3 CHCH2OH + Ca(OH)2CH3 CHCH2Cl + CH3 CHCH2 OHOHCl2CH3 CHCH2 + CaCl2 + 2H2 OOOHC lpropylene using ethylbenzene hydroperoxide or tert-butyl hydroperoxide as the organic peroxide.

8 A styrenemonomer (SM) or tert-butanol (TBA) is produced asthe co-product. Typical producers using PO/SM co-production are Lyondell Chemical Company and ShellChemicals Ltd., and in Japan, there is only Nihon Oxi-rane Co., Ltd. The PO/TBA producers are Lyondelland Huntsman International LLC. In a reflection of thetrends in demand for the two sets of co-products inrecent years, new PO plants have exclusively employedthe PO/SM co-production method. We will describethe PO/SM co-production Process in the of all, ethylbenzene hydroperoxide is producedby air oxidation of ethylbenzene. Next, the ethylben-zene hydroperoxide and Propylene are reacted in thepresence of an epoxidation catalyst, and -methylben-zyl alcohol and PO are produced.

9 The -methylbenzylalcohol that is produced undergoes a dehydration reac-tion in the presence of an acid catalyst to form SM. Mobased homogeneous catalysts3)and Ti supported silicabased heterogeneous catalysts4), 5)are used for theepoxidation catalyst. With the isobutane method, thereis co-production of TBA. If TBA is dehydrated, it formsisobutylene, and if it is further reacted with methanol,methyl tertiary-butyl ether (MTBE), which is useful asa gasoline additive, can be organic peroxide methods use the oxidativepower of hydroperoxides skillfully and have the superi-or characteristic of not requiring the secondary rawmaterials such as chlorine. However, with the ethylben-zene method, approximately tons of styrene is co-produced for every ton of PO, and with the isobutanemethod, tons of isobutylene is co-produced for eachton of PO.

10 Since these co-products are severely affectedby market conditions, it is difficult to say that these arealways the optimal methods for producing KAGAKU 2006-IDevelopment of New Propylene Oxide ProcessSumitomo Chemical s New PO-only ProcessUsing cumene, sumitomo Chemical has establisheda cumene PO-only Process as a new PO productionprocess. We developed a high performance Ti basedepoxidation catalyst in 1998, and taking this as anopportunity, we started working on developing a newPO-only Process using cumene. Starting with the labo-ratory investigations in 1999, it was possible to carryout Development and establish the business in a shorttime by maximizing the use of concurrent engineering,with bench tests in 2000, pilot testing in 2001, comple-tion of a plant in 2002 and plant startup in production method is fundamentally similar tothe organic peroxide methods, but the major feature isusing a high performance epoxidation catalyst thatuses cumene as the reaction medium, so we can call itthe cumene PO-only Process .