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Mitsui unit to make aniline from phenol
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LABORATORY
I • J J A EQUIPMENT I d d U L J CORPORATION 1415 Hilltop Road St. Joseph, Michigan 49085, U.S.A.
44 C&EN MARCH 31, 1969
Lubowitz and technician A stable and exciting intermediate
stage can itself be produced in a variety of viscosities from the slightly viscous to the rubbery intermediate, depending on the ratio of resin to chain extender. Thus, for a molding formulation, the mixture may be injected in a fluid form, then made viscous in the mold, then cured. In another application, a rubbery intermediate sheet may be made, and this can be draped over a matched die mold with a complicated structure, then cured. For coatings and laminates, viscosities between the two extremes can be made. Lubowitz stresses that the two steps in making the plastics are separate and different reactions. The polyurethane intermediate is prepared at the relatively low temperature of 150° F. There is no creeping cure, as the cure step needs a kickoff temperature and takes place at about 300° F . The intermediate, or Bstage, is stable at room temperature for more than six months and at 130° F . for 750 hours. The cured resins are indeed tough and chemically resistant (see table). The materials also have high dielectric strengths and low dielectric losses. They have a heat distortion temperature of about 500° F., equal to the best anhydride-cured epoxides, Lubowitz says, although not as good as polyimides. They also show in laminates a flexural strength of 100,000 p.s.i.—equal to the best acidcured epoxides. They have a much shorter curing time than epoxides, however. Lubowitz doesn't yet know the exact structure of the cured polymer. He describes it only as a cross-linked ladder structure stemming from condensed cyclohexane groups with some residual unsaturation. At the present time, the polybutadienes and their hydroxy and carboxy variations are coming from Nippon Soda's semiworks plant near Tokyo. A commercial plant there is expected to go on stream in spring 1971. When it is needed, H D C and Nippon Soda will build a polybutadiene plant in Puerto Rico, using butadiene from a CORCO plant there.
The third generation of aniline processes may use phenol as a raw material. At least, Halcon International has banked its research efforts in this direction. Halcon has developed a phenol-toaniline process which the firm says has a number of advantages, chief of which is purity of the product. Halcon also says that capital costs are lower than for processes based on the conventional nitrobenzene raw material, and that yields are nearly quantitative at high conversions. Mitsui Petrochemical Industries, Ltd., will build the first plant using; the process at Chiba, Japan. Scientific Design, a subsidiary of Halcon, will design the 44 million pound-per-year plant (C&EN, March 17, page 3 7 ) . The Halcon process for producing aniline via the ammonolysis of phenol may be more attractive to foreign producers than to U.S. chemical companies. Domestic producers have captive sources of nitrobenzene and aren't likely to switch to a different feedstock. The present price differentials between phenol and nitrobenzene also seem to offer little inducement for U.S. producers to shift. Phenol lists for 9.5 cents a pound compared to nitrobenzene's list of 8.5 cents a pound. In the Halcon process, phenol is reacted with ammonia to produce aniline and water. Most processes are based on the catalytic vapor phase hydrogenation of nitrobenzene to produce aniline and water. Aniline is an intermediate chemical that showed only a 3 % a year compounded production growth between 1953 and 1963. In the past five years, however, production has climbed 11% a year compounded. In 1968, aniline production was about 263 million pounds, according to the Tariff Commission. Major U.S. producers of aniline are Du Pont and American Cyanamid, each with about 100 million poundper-year capacity. Mobay has 70 million, Rubicon Chemical 40 million, First Chemical 50 million, and Allied Chemical 40 million. The bright spot in aniline's future is in the growing market for rigid urethane foams. Polymeric isocyanates of the diphenyl methane diisocyanate type are raw materials for these foams. This end use accounts for about 17% of consumption of aniline at present. Other uses are: rubber chemicals 5 1 % , dyes 10%, miscellaneous 9%, photographic chemicals (hydroquinone) 8%, medical and veterinary medicines 5 % .
