Gasoline oxygenates such as methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME) and tert-amyl ethyl ether (TAEE) are produced commercially by the reaction of olefins (IB and isoamylenes) or C4-C7 hydrocarbons with MeOH or EtOH, in the presence of homogeneous catalysts (e. g. H2SO4) or a heterogeneous catalysts (e. g. ion — exchange resin) as shown in Figure 1, in case of ETBE.

Figure 1. Reaction scheme for ETBE synthesis using IB as a reactant

The differences of blending characteristics of the ether oxygenates are summarized in Table 1.

Brockwell et al. [3] discussed the process schemes for the production of these ethers. The schemes generally consist of primary reactor, distillation column and additional column to purify the products (e. g. extractor). Due to the upsurge of the demand for gasoline oxygen­ates, the MTBE process having a world production capacity of 20 million tons per year in 1994 [4] is the most established one. With legislations banning MTBE, it is assumed that the currently existing processes for the production of MTBE can be converted for ETBE produc­tion. Similarly, the processes can be integrated for MTBE and TAME production, since these ethers are both produced from MeOH [3].

Some of the patented processes for the production of ether oxygenates are reported in "Re­fining 1996" [5]. The main features of each process are summarized here.