Isomerization technology, advances

Moore, J.A. and Bunting, W.W. (1985) Polyesters and polyamides containing isomeric furan dicarboxylic acids. Polymer Scienceand Technology, Advanced Polymer Synthesis, 31, 51-91. 

ShelP published information on the biodegradability of methyl-substituted surfactants. The Shell and P G research paved the way for new anionic surfactant design with controlled alkyl substitution on the hydrophobe and acceptable biodegradability. Selective isomerization of the linear olefins using recent advances in zeolite catalytic sieve technology are the key technology advancements for these new surfactant hydrophobes, which require only one additional step in the current Shell linear alcohol process as shown in Figure 6.14. 

The catalysts for xylene isomerization with EB dealkylahon are dominated by MFI zeolite. The de-ethylation reaction is particularly facile over this zeolite. There have been several generations of catalyst technology developed by Mobil, now ExxonMobil [84]. The features in their patents include selectivation and two-catalyst systems in which the catalysts have been optimized separately for deethylation of EB and xylene isomerization [85-87]. The crystallite size used for de-ethylation is significantly larger than in the second catalyst used for xylene isomerization. Advanced MHAI is one example. The Isolene process is offered by Toray and their catalyst also appears to be MFI zeoUte-based, though some patents claim the use of mordenite [88, 89]. The metal function favored in their patents appears to be rhenium [90]. Bimetallic platinum catalysts have also been claimed on a variety of ZSM-type zeolites [91]. There are also EB dealkylation catalysts for the UOP Isomar process [92]. The zeolite claimed in UOP patents is MFI in combination with aluminophosphate binder [93]. 

Fischer-Tropsch (FT) technology converts synthesis gas produced by reforming of methane or coal gasification into waxy products. Long alkanes (-CH2 -chains) produced by using FT synthesis are chemically similar to polyethylene. Lubricating oils derived from isomerization of FT waxes are gaining interest due to increased demand for lubricants with the advanced performance and environmental benefits described earlier. 

Bovine milk fat has been reported to contain 400 or more fatty acids (1). Caprine and ovine milk fats have not been as extensively examined but could be assumed to contain a similar number of fatty acids since the ruminal processes are similar in these two species. Humans have been consuming these fatty acids in meat and milk products since prehistory when ruminant species became food sources for mankind. The variety and chemical composition of milk lipids is truly amazing. Within the last hundred years many lipid classes, individual fatty acids, and isomeric fatty acids have been identified as analytical capabilities increased. Recent advances in technology have allowed the identification and characterization of specific isomers of fatty acids present in milk fat that contain single cis or trans double bonds (monoenes) and conjugated double bonds (CLA) with none, one, or two trans bonds. These techniques of gas chromatography and HPLC with silver ion columns are described in Volumes 1 and 2 of this series. 

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