Successes in the laboratory but . . .

A new nylon (adiponitrile) synthesis

In 1957 British Nylon Spinners, a joint company of ICI and Courtauld's, started up nylon spinning operations from imported polymer at their brand new factory at Bayswater, Victoria. In 1963 the partners separated and the Bayswater plant became a wholly owned ICI Australia subsidiary, Fibremakers Pty. Ltd.

In the spirit of national ambitions in manufacturing and ICI's plans to build a major petrochemicals cracker, researchers and planners gave some thought to backward integration -nylon 66 polymer manufacture. The planners were sceptical; the complex synthesis of nylon from yclohexane/cyclohexanol/cyclohexanone to adipic acid and from it to adiponitrile and hexamethylenediamine on an Australian scale plant, even with export and some tariff protection, seemed just too ambitious. However, researchers are optimists, so at least they kept their eyes open for entirely new processes. When in the early sixties ICI Australia's plans for the Botany cracker showed that there might be a substantial surplus of propylene they recalled a Russian publication by Knunyants,[96] which had suggested a new route, the hydrodimerisation of acrylonitrile to adiponitrile which could be easily reduced to hexamethylenediamine. Also recently a much cheaper route to acrylonitrile had emerged, the Sohio ammoxidation process from propylene and ammonia. A simplified scheme of the processes is set out below, for the technically inclined reader:[97]

Adiponitrile is the precursor of hexamethylenediamine, the most expensive part of the nylon molecule. ICI Australia had ammonia, amalgam (providing hydrogen as a by-product) and would soon have by-product propylene -was this a chance? For highly speculative, high risk work of this nature Research Department had a handsome allocation of its budget -some 30 per cent -which only needed the Research Manager's (W. I. Whitton) approval. He promised support if Knunyants' low yields could be bettered within reasonable time. The late Bob Dewar combined the experience of an old research hand (he was Associate Research Manager) with a young man's single-minded imagination. He also had useful experience with amalgam and mercury cells which produce the amalgam. With some good advice on the cost structure of nylon and pathways through the maze of patents and with the help of two young researchers (V. M. Maier, Mrs. M. A. Ingram, nee Riddols)[98] he devised experiments aimed at controlling the reduction of acrylonitile to the half-way stage and preventing the full reduction to propionitrile. Postulating that surface active agents might intercede in the process, particularly if appropriately shaped, the team eventually found the ideal agent, long chain aliphatic quaternary surfactants. The concept proved spectacularly successful and led to rapid elimination of propionitrile. Results were so outstanding that a large project team was assembled to explore variables, chemical engineering aspects and provide patent data. When the patents and reports reached the UK, their importance was recognised immediately. ICI Australia claimed a potential saving in adiponitrile production of 20 to 30 per cent; with nylon 66 production of some hundreds of thousands of tonnes, much of it in ICI's hands, such claims had to be verified on a larger scale and with the critical expertise of the experienced producer, ICI Dyestuffs Division. The potential was important to ICI and ICI Australia but even greater was the potential of world-wide licensing. The project found an enterprising supporter in the Manager of ICI UK's Corporate Research Laboratory (later General Manager of ICI R&D London), the late Dr. Duncan S. Davies. He assembled a second, large team of some 40 researchers in the UK to support ICI Australia's team of some 20-25, built a substantial pilot plant and encouraged corporate interest. Over some three years the teams worked side by side on separate but coordinated aspects of the project. Performance data were confirmed and overseas licence enquiries arrived. The Japanese were interested; they produced nylon 6 only from a single starting product, caprolactam, but nylon 6 had some disadvantages, e.g. flat spotting of nylon 6 tyres. Prolonged licensing discussions took place. Further process improvements were found[99][100][101] and hopes for acceptance of the process were high.

For the technically inclined: Sohio ammoxidation process from propylene and ammonia

Australian Academy of Technological Sciences and Engineering