China
Africa
Explore chapters and articles related to this topic
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Another configuration or variation in structure of a straight chained hydrocarbon is the “ringed” compound. All carbons in the ringed compound are hooked together end to end. Ringed compounds are referred to as cyclic, and when a ringed compound is named, the prefix “cyclo” is used in front of the hydrocarbon name. This configuration can be very unstable in the case of three or four carbons, or seven or eight carbons. However, five or six carbons in a ring form a stable compound. Arranging carbons in a circle tends to raise the boiling point of the material (Figure 3.48). For example, hexane is a six-carbon straight chained compound with a boiling point of around 155°F. Cyclohexane, on the other hand, has a boiling point of around 178°F.
Solvent Exposure and Toxic Responses
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
Alicyclic hydrocarbons are saturated or unsaturated molecules in which three or more carbon atoms are joined to form a ring structure. The saturated compounds are called cycloalkanes, cycloparaffins, or naphthenes. The cyclic hydrocarbons with one or more double bonds are called cycloalkenes or cyclo-olefins. Cyclohexane is the only alicyclic hydrocarbon that is widely used as an industrial solvent for fats, oils, waxes, resins, and certain synthetic rubbers, and as an extractant of essential oils in the perfume industry. However, most of the cyclohexane produced is used in the manufacturing of nylon. Cyclo-hexene is used in the manufacture of adipic, maleic, and cyclohexane carboxylic acid. Methylcyclohexane is used as a solvent for cellulose ethers and in the production of organic synthetics.
Chemicals from Aromatic Hydrocarbons
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Benzene and its derivatives convert to cyclohexane by hydrogenation. Cyclohexane is a colorless liquid, insoluble in water but soluble in hydrocarbon solvents, alcohol, and acetone. As a cyclic paraffin, it can be easily dehydrogenated to benzene. The dehydrogenation of cyclohexane and its derivatives (present in naphthas) to aromatic hydrocarbon derivatives is an important reaction in the catalytic reforming process. Essentially, all of the cyclohexane is oxidized either to a cyclohexanonecyclohexanol mixture used for making caprolactam or to adipic acid. These are monomers for making nylon 6 and nylon 6/6.
Chemical permeation of similar disposable nitrile gloves exposed to volatile organic compounds with different polarities: Part 1: Product variation
Published in Journal of Occupational and Environmental Hygiene, 2020
Brittany Claire Brown, Anton Dubrovskiy, Aleksandre Roman Gvetadze, Robert N. Phalen
Chemical permeation testing was conducted using three volatile organic solvents of varying polarities, which are summarized in Table 2 with the addition of ethanol for later comparison to results from a previous study by Pham et al. (2015). Different polarity parameters were evaluated, as there was some variation in observed trends among the solvents tested. All chemicals were reagent grade and obtained from Fisher Scientific (Houston, TX). Cyclohexane (Fisher, 99.9%) is virtually insoluble in water and was used to represent a non-polar solvent. Cyclohexanol (Acros Organics, 98%, Themo Fisher Scientific, NJ) is slightly soluble in water and was used to represent a moderate polar solvent. tert-Butanol (Acros Organics, 99.5% extra pure, Themo Fisher Scientific, NJ) is miscible in water and was used to represent a polar solvent.