Production of ASA

The dicarboxylic acid product of ASA hydrolysis (see Figure 7.16) is inhibitory to sizing and this behaviour contrasts with that of AKD sizing, where the product of hydrolysis is not inhibitory. Both sizes... 

The industrial production of ASA has been dominated by the Reichstein-Grussner process (Fig. 8.29) [146] since the mid 1930s. Although the intermedi-... 

Genencor and Eastman have announced plans for the production of ASA [169], presumably based on either the fermentative or the in vitro processes developed by Genencor. 

Fig. 8.31 Production of ASA in an in vitro multienzyme system. Compounds and enzymatic activities as in Fig. 8.30b GlcDH, glucose dehydrogenase.

Molecular evidence that a functionally unassigned open reading frame in Arabidopsis does, in fact, encode a putative MIOase has just been reported (Lorence et al., 2004). In this study, MIOase provides a possible entry point into AsA biosynthesis. Those concerned with MIOase and its role in the MIOP will now have the opportunity to extend these findings to breakdown products of AsA catabolism (Banhegyi and Loewus, 2004) as well as to cell wall biogenesis. 

Separation and identification of initial autoxidation products of ASA in MeOH were carried out, and formation of DHA was positively confirmed as the main oxidation product of ASA. Threonolactone was identified as its TMS derivative, 2,3-di-O-trimethylsilyl-L-threonolactone, by comparing its GC retention time with that of the authentic compound, and further confirmed by comparing the mass spectrum of the sample with the authentic mass spectral data reported in the literature (3). The formation of oxalic acid was similarly confirmed by GC and GC-MS analyses. These reaction products were also detected in the autoxidation of ASA monoanion as an ASA-Na salt solution in MeOH, and the formation of the same oxidation products was confirmed in the autoxidation of ASA in an aqueous solution. It was also confirmed, however, that these autoxidation reaction products of ASA were not formed from DHA. Therefore, this appears to be a new autoxidation pathway of ASA that does not proceed via DHA, and this pathway might be involved in various oxidation processes observed in food and biological systems. 

Other Uses. A small but growing oudet for C and higher linear olefins is the production of alkenylsuccinic anhydride (ASA) for the paper iadustry. ASA is an effective alkaline sizing agent and competes with alkylketene dimer (AKD) ia this appHcatioa. 

Compositions made from pellets of ASA, vinyl chloride containing polymers, and wood can be extruded to form weatherable products or materials (21). 

De-novo fermentation of ASA in an acid-tolerant yeast, combined with in-pro-cess product removal, has the potential of eliminating salt production altogether. Unfortunately, there is no microbe that naturally produces ASA and the reported yields are minute until now [176]. 

Styrenic copolymers are materials capable of thermoplastic processing which, in addition to styrene (S), also contain at least one other monomer in the main polymer chain. Styrene-acrylonitrile (SAN) copolymers are the most important representative and basic building blocks of the entire class of products. By adding rubbers to SAN either ABS (acrylonitrile-butadiene-styrene) or ASA (acrylate-styrene-acrylonitrile) polymers are obtained depending on the type of rubber component employed. These two classes of products yield blends composed of ASA and polycarbonate (ASA -f PC) or ABS and polyamide (ABS -(- PA). 

Since most of the manufacturers of ASA make use of multipurpose production plants that are used for both ABS and ASA production, the ASA output can be adapted to demand. It is estimated, that the annual demand for ASA is in the range 1-5% of the annual ABS demand (ABS demand 2001 ca4.5 x 106/t [1]). 

In most of the commercial products butyl acrylate is employed however, in the majority of the ASA patent literature, other acrylates, especially ethylhexyl acrylate, are mentioned. The advantage of the latter over poly(butyl acrylate) is its lower glass transition temperature (Tg), —65°C, compared with poly(butyl acrylate) with a value of —45°C. This lower Tg opens up the way for better low-temperature properties for the ASA. The low-temperature properties of ASA are touched on briefly in Section 5. 

Blends of ASA with many of the common thermoplastic materials are state of the art. The properties of the finished products depend to a large extent on the polymer compatibility often induced by the use of reactive polymers. Only a few of these blends have reached a significant commercial status. The largest blend products in this area are ASA-PC blends followed by ASA-PBT and ASA-PC-PMMA blends. Combinations of ASA with high-Tg matrix polymers are also frequently found in commercial products. 

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