technologyComment of Mannheim process (RER): Production of sodium sulfate and HCl by the Mannheim process. This process can be summarized with the following overall stoechiometric reaction: 2 NaCl + H2SO4 → Na2SO4 + 2 HCl technologyComment of allyl chloride production, reaction of propylene and chlorine (RER): based on industry data in the US and Europe technologyComment of benzene chlorination (RER): Clorobenzenes are prepared by reaction of liquid benzene with gaseous chlorine in the presence of a catalyst at moderate temperature and atmospheric pressure. Hydrogen chloride is formed as a by-product. Generally, mixtures of isomers and compounds with varying degrees of chlorination are obtained, because any given chlorobenzene can be further chlorinated up to the stage of hexa-chlorobenzene. Because of the directing influence exerted by chlorine, the unfavoured products 1,3-dichlorobenzene, 1,3,5-trichlorobenzene and 1,2,3,5-tetrachlorobenzene are formed to only a small extent if at all. The velocity of chlorination for an individual chlorine compound depends on the compound's structure and, because of this, both the degree of chlorination and also the isomer ratio change continuously during the course of reaction. Sets of data on the composition of products from different reactions are only comparable if they refer to identical reaction conditions and materials having the same degree of chlorination. By altering the reaction conditions and changing the catalyst, one can vary the ratios of different chlorinated products within certain limits. Lewis acids (FeCl3, AlCl3, SbCl3, MnCl2, MoCl2, SnCl4, TiCl4) are used as principal catalysts. The usual catalyst employed in large scale production is ferric chloride, with or without the addition of sulfur compounds. The ratio of resulting chlorobenzenes to one another is also influenced by the benzene:chlorine ratio. For this reason, the highest selectivity is achieved in batch processes. If the same monochlorobenzene:dichlorobenzene ratio expected from a batch reactor is to result from continuous operation in a single-stage reactor, then a far lower degree of benzene conversion must be accepted as a consequence of the low benzene:chlorine ratio). The reaction is highly exothermic: C6H6 + Cl2 --> C6H5Cl + HCl ; delta H = -131.5 kJ/mol Unwanted heat of reaction can be dissipated either by circulating some of the reactor fluid through an external heat exchanger or by permitting evaporative cooling to occur at the boiling temperature. Circulation cooling has the advantage of enabling the reaction temperature to be varied in accordance with the requirements of a given situation. Evaporative cooling is more economical, however. Fractional distillation separates the products. Iron catalyst is removed with the distillation residue.Unreacted benzene is recycled to the reactor. technologyComment of hydrochloric acid production, from the reaction of hydrogen with chlorine (RER): HCl can be either directly prepared or generated as a by-product from a number of reactions. This dataset represents the production of HCl via the combustion of chlorine with hydrogen gas. The process involves burning hydrogen gas and chlorine in a gas combustion chamber, producing hydrogen chloride gas. The hydrogen chloride gas then passes through a cooler to an absorber where process water is introduced, producing aqueous hydrochloric acid. H2 + Cl2 -> 2 HCl (exothermic reaction) References: Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. ecoinvent report No. 8, v2.0. EMPA Dübendorf, Swiss Centre for Life Cycle Inventories, Dübendorf, CH. technologyComment of tetrafluoroethylene production (RER): The production of fluorochemicals and PTFE monomers can be summarized with the following chemical reactions (Cedergren et al. 2001): CaF2 + H2SO4 -> CaSO4 + 2HF (1) CH4 + 3Cl2 -> CHCl3 + 3HCl (2) CHCl3 + 2HF -> CHClF2 + 2HCl (3) 2 CHClF2 + heat -> CF2=CF2 + 2 HCl (4) This dataset represents the last reaction step (4). Parts of the production are carried out at high pressure and high temperature, 590 ºC – 900 ºC. The first reaction (1) takes place in the presence of heat and HSO3 - and steam. The inventory for the production of hydrogen fluoride can be found in the report (Jungbluth 2003a). Reaction (2) is used to produce trichloromethane. Reaction 3 for the production of chlorodifluoromethane takes place in the presence of a catalyst. The production of PTFE (4) takes place under high temperature pyrolysis conditions. Large amounts of hydrochloric acid (HCl) are generated as a couple product during the process and are sold as a 30% aqueous solution. A large number of other by-products and emissions is formed in the processes (benzene, dichloromethane, ethylene oxide, formaldehyde, R134a, and vinyl chloride) and small amounts of the highly toxic perfluoroisobutylene CF2=C(CF3)2. The by-products in the production of monomers can harm the processes of polymerisation. Because of this, the refinement of the production of monomers has to be very narrow. This makes the process complex and it contributes to a high cost for the PTFE-laminates. (Cedergren et al. 2001). References: Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. Final report ecoinvent data v2.0 No. 8. Swiss Centre for Life Cycle Inventories, Dübendorf, CH.