INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE 

Case Study #61



1.   Headline: A process for the production of

     dimethylcarbonate (DMC) directly from carbon monoxide and

     methanol instead of the old method based on phosgene.



2.   Background: See Description of Cleaner Production

     Application



3.   Cleaner Production Principle: New technology



4.   Description of Cleaner Production Application: The case

     study was performed in 1993. The synthesis of DMC is based

     on oxidization of the catalyst, cuprous chloride, using

     oxygen, which yields CU(2) and methoxichloride and results

     in the reduction of the latter to dimethylcarbonate, using

     CO. In this way, the cuprous chloride is regenerated and a

     catalytic cycle is established in a heterogenous phase

     which produces DMC. The salient features of this process

     are:



     1) the use of low-cost and widely available raw materials

     with low toxicity;

     2) the technology can be easily be adapted to high

     production rates;

     3) the major significant by-products are carbon dioxide

     and water; and

     4) the product is of high quality.



     The DMC produced by this method is characterized by the

     virtual absence of chlorinated impurities. The DMC

     production technology produces no by-products that are

     difficult to dispose of. The DMC obtained with this

     technology has low toxicity and ecotoxicity

     (biodegradability >90% at 28 days - OECD 301C; acute

     toxicity for fish; no effect at 1000 mg/l - OECD 203).



     The use of DMC instead of phosgene, dimethylsulphate, or

     methyl chloride, decreases or eliminates altogether the

     toxicological and environmental problems connected with

     their use, transportation or storage. For example: the

     formation of large quantities of waste fluids containing

     HCl and NaCl (using phosgene) or NaCL and Na2SO4 (using

     dimethylsulphonate); and high toxicity and volatility

     (using methyl chloride).



     At the Revena plant the DMC production is 8,000 tons per

     year. This process eliminates the formation of large

     quantities of waste fluids containing UCl and NaCL (using

     phosgene) or NaCL and Na2SO4 (using dimethylsulphate). The

     technology has been fully implemented and in operation

     since 1988.



     Wastes and emissions generated were reduced from 1.69 to

     0.39 (Kg/Kg). Water usage was reduced from 0.02 (m3/Kg) to

     virtually zero. Energy use was reduced from .01(Kwh/Kg) to

     .04 (Kwh/Ka).



5.   Economics: See Description of Cleaner Production

     Application



6.   Advantages: The DMC production technology uses no toxic

     materials and produces no by-products or co-products that

     would be difficult to dispose of. The DMC obtained this

     new technology has very low toxicity and ecotoxicity. The

     use of DMC instead of Phosgene, dimethylsulpahte or methyl

     chloride decreases or eliminates altogether the

     toxicological and environmental problems connected with

     their use, transportation and storage.



7.   Constraints: No information was provided



8.   Contacts:



     Dr Roberto Ciapponi

     Enichem Synthesis SpA

     Via Medici del Vascello 4

     20138 Milano Italy

     TEL: 39 2 520 39465

     FAX: 39 2 520 39354



     Mr G Bardone

     ENEA CRE Casaccia

     Dip Ambiente

     Via Anguillarese 301

     00060 - S Maria di Galeria ROME

     Italy

     TEL: 396 3048 6662

     FAX: 396 3048 3220



9.   Keywords: Italy, chemical, dimethylcarbonate, DMC, new

     technology, phosgene, catalyst



10.  Reviewer's comments: This case study was submitted to UNEP

     IE in 1994 by Italy's ENEA. It was reviewed and edited by

     UNEP IE in July 1995. It has not undergone a formal

     technical review.