Itaconic add

Itaconic add was discovered in 1929 as a metabolite of an Aspergillus spedes which was subsequently named Aspergillus itaconicus. A short time later A. terreus was shown to accumulate the acid and one particular strain of this, superior to all others, is still the current industrial producer of itaconic add. 

Originally itaconic acid was produced chemically by the pyrolysis of dtric add. The treatment results in water loss converting dtric add to aconitate. Subsequent decarboxylation of the latter gives two isomers, itaconic add and dtraconic add. The process was not very successful, partiy because sucdnate and itatartaric adds were also produced. 

With A as the major pathway, it is reasonable to assume that there would be no effect on itaconic add production since aconitase is not involved. In fact it was shown that tiie presence of copper ions increases the yield of itaconic add by a factor of up to 3. 

These facts indicate that the major or only pathway involved in itaconic add production is pathway A. 

The empirical formula for glucose is C6H12O6 and for itaconic add it is C5H6O4, so itaconic add production is another aerobic fermentation and requires aeration. 

Figure 5.10 Downstream processing in itaconic add production. Any of the four products can be esterified as required.

The filtrate following carbon treatment is evaporated, allowed to cool and crystallised. This yields refined grade itaconic add. The solution may be further evaporated to yield a second sample - this time designated industrial grade. Industrial grade samples can also be made directly by evaporating the fermentative filtrate and thus avoiding the activated carbon step. 

If itaconic add esters are required, esterification of any of the grades can be carried out yielding esters of varying purity. 

Give three reasons why it is believed that the formation of itaconic add in A. terreus is via a route which does not involve TCA cyde intermediates. 

Conversion of itaconic add via dtraconic add and itatartaric add has been demonstrated. 

Evidence for the firm binding of Zn comes from studies using labelled zinc polyacrylate containing Zn and C. Only small amounts of these ions were lost to a saline solution over a three-month period, even in the presence of calcium (Peters et al., 1972 Peters, Jackson Smith, 1974). There is some evidence, from leaching studies, that Zn is more firmly bound to a copolymer of acrylic and itaconic adds than to poly(acrylic acid), and less firmly bound to a copolymer of maleic and acrylic adds. 

The poly(alkenoic acid)s used in glass polyalkenoate cement are generally similar to those used in zinc polycarboxylate cements. They are homopolymers of acrylic acid and its copolymers with itaconic add, maleic add and other monomers e.g. 3-butene 1,2,3-tricarboxylic add. They have already been described in Section 5.3. The poly(acrylic add) is not always contained in the liquid. Sometimes the dry add is blended with glass powder and the cement is activated by mixing with water or an aqueous solution of tartaric add (McLean, Wilson Prosser, 1984 Prosser et al., 1984). 

Of a similar character is the relation subsisting between the isomeric adds of this series containing five atoms of carbon, viz. itaconic add, dtraconio add, and mesaconic add. There are no less than eleven possible formulm for this five. cbon group of acids but the three individual formule belonging to the three known adds cannot at present he determined. The following four formula will serve as specimens of the whole, and as illustrations of the cause of isomerism in these adds... 

MAn/MMI copolymer of maleic anhydride and monomethyl ether of itaconic add... 

Reactivity of itaconic add in copolymerization is dependent upon pH and degrees of ionization of the add. Acid reactivity has been studied most carefully in acrylonitrile copolymerization 33, 37). Under acidic conditions an increase in itaconic concentration greatly decreases the polymerization rate, while at pH s of 7—9.8 moderate increases of itaconate do not reduce the rates so strongly. Monomer reactivity ratios and Q and e values have been calculated for the various states of ionization of the acid as reported in Table 5. As the pH rises, drops from 1.57 to 0.1 suggesting, as stated earlier, that the dianion undergoes little homopolymerization. The change in is less than 2-fold which indicates appreciable copolymerization of the dianion. The much greater decrease... 

Itaconic add homopolymers, and certain copolymers, decarboxylate partially on heating under unusually mild conditions (7). In the absence... 

The compound itaconic add - or methylene succinate - is a substituted methacrylic add having the structural formula ... 

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