Process Economics Program Report 75
Dibasic Acids for Nylon Manufacture
Published: October 1971
Although more than fifty dibasic acids have been claimed to be suitable for preparation of nylons (polyamides) only five are used for this purpose commercially: adipic, dodecanedioic, isophthalic, sebacic, and terephthalic, Adipic acid has been the subject of Process Economics Program Report Nos.3 and 3A; terephthalic acid, Report No.11. Isophthalic acid is made by processes analogous to those for terephthalic acid. The remaining two, dodecanedioic acid and sebacic acid, are included in this report, along with two additional dibasic acids that have potential for commercial use in nylons--azelaic acid and suberic acid. All four of these acids have other uses as well.
Dodecanedioic acid and suberic acid are made respectively from cyclododecatriene and cyclooctadiene. One process for sebacic acid starts with cyclodecadiene. These three cyclic hydrocarbons, which are also the precursors of nylon 12, nylon 8, and nylon 10 through the intermediate formation of lactams, are also included in this study.
Processes were evaluated for: the manufacture of cyclododecatriene, cyclooctadiene, and cyclodecadiene; the manufacture of dodecanedioic acid, suberic acid, and sebacic acid from these cyclic hydrocarbons via the saturated cyclic hydrocarbons; the manufacture of dodecanedioic acid from cyclododecatriene by another process, namely, via cyclododecene;the manufacture of sebacic acid by alkali cleavage of castor oil; the manufacture of sebacic acid from adipic acid by electrolysis; the manufacture of azelaic acid by ozonolysis of oleic acid; and a process of oxidation of tallow to give sebacic acid, suberic acid, and azelaic acid. Other processes for manufacture of these four dibasic acids are briefly described.