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Safety Data Sheets, Green Movement, and More
Published in Kathleen Hess-Kosa, Building Materials, 2017
SDS require the identity of substances and mixtures that are designated by the Hazard Communication Standard as hazardous. A substance is a single chemical or component which has a unique CAS number and may be inclusive of low level, high risk chemicals/components such as the carcinogen asbestos. Mixtures are two or more substances that are classified as health hazards. The concentration of each ingredient must be specified (i.e., exact percentage by weight) except where (1) there are batch-to-batch variations; (2) the same SDS is used for a group of similar mixtures; and (3) a component is a trade secret. Furthermore, if not listed by OSHA or the ACGIH as a toxic substance, a substance or component of a mixture does not have to be listed. For example, caprolactam, an irritant and a mild toxin, is widely used in manufacturing synthetic nylon, but it is not listed as a toxin by either OSHA or the ACGIH. Caprolactam has, however, been identified by NIOSH as a dust health hazard with a recommended exposure limit (REL) of 1 mg/m3 and a vapor health hazard of 0.22 ppm. NIOSH RELs do not have to be listed!
Polymers: Making New Materials
Published in Richard J. Sundberg, The Chemical Century, 2017
Caprolactam continues to be the key intermediate for preparation of nylon-6. It was originally made by Beckman rearrangement of cyclohexanone oxime. For a time, the oxime was made from nitrocyclohexane. The Beckman rearrangement step generates ammonium sulfate as a byproduct that was sold as a fertilizer. Alternatively, reaction of cyclohexanone with air, ammonia, and hydrogen peroxide to form the oxime, followed by solid phase catalysis can provide caprolactam with water as the only byproduct.12 In another procedure, caprolactam was made by Baeyer–Villiger oxidation of cyclohexanone to caprolactone, which was then converted to caprolactam by ammonia. Another process goes through phenol, which is made from benzene by hydroxylation using nitrous oxide. The nitrous oxide is produced as a byproduct of the oxidation of cyclohexanone to adipic acid by nitric acid.13
Plastics
Published in Ronald M. Scott, in the WORKPLACE, 2020
Nylons may be prepared using diacids or diacid chlorides which are reacted with diamines. The diacids are not serious problems, but diacid chlorides are similar to acid anhydrides in properties, and cause severe skin or eye damage. The diamines are irritants and sensitizers, and so also must be carefully handled. Caprolactam, used to make Nylon 6, causes nose and throat irritation, irritability, and nervousness.
Photo-catalytic selective organic transformations by Fe-doped octahedral molecular sieves (manganese oxide) nano-structure
Published in Journal of Asian Ceramic Societies, 2018
S. Said, Heba H. El Maghrabi, M. Riad, S. Mikhail
The selective oxidation of hydrocarbons involving the activation of C-C, C-H bonds and/or the concomitant formation of C-OH or C = O bonds to produce more suitable products (for fine chemical synthesis) is a must [1]. Cyclohexane oxidation products (cyclohexanol and cyclohexanone) are important reagents for the production of caprolactam, adipic acid and monomers to prepare nylon-6 and nylon-6,6 polymers. Currently, the industrial processes for cyclohexane oxidation on using cobalt salts or metal–boric acid with molecular oxygen as an oxidant have some inherent drawbacks (lower conversion and selectivity, expensive investment) and cause serious pollutions [2].