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Non-Edible Biodegradable Plant Oils
Published in Jitendra Kumar Katiyar, Alessandro Ruggiero, T.V.V.L.N. Rao, J. Paulo Davim, Industrial Tribology, 2023
Zahid Mushtaq, M. Hanief, Kaleem Ahmad Najar
Epoxidation is a very useful process because of its ability to perform a long range of reactions in ordinary conditions. Epoxides are formed by the reaction of alkenes and peroxy acid. The epoxidized vegetable oils can be manufactured by the reaction of peroxy acids with double bonds. They have better anti-friction characteristics but have poor high-temperature stability. After the epoxidation, the epoxidized oil is subjected to the ring-opening and esterification process [40, 41].
Polymerization of 1,2-Epoxides
Published in F. E. Bailey, Joseph V. Koleske, Alkylene Oxides and Their Polymers, 2020
F. E. Bailey, Joseph V. Koleske
After World War II, very large quantities of three epoxides were being produced: ethylene oxide, propylene oxide, and epichlorohydrin. These three epoxides found a wide variety of uses, including lubricants, surfactants, plasticizers, adhesives, coatings, and solvents. The first uses involved polymers of ethylene oxide and propylene oxide with molecular weights in the range of several hundred to a few thousand as lubricants and surfactants and epichlorohydrin derivatives incrosslinked (epoxy) adhesives. During the latter 1950s, polymerization mechanisms were found that would produce truly high-molecular-weight polymers of vicinal epoxides, as well as ways of controlling the stereoregularity of the polymerization of substituted ethylene oxides and the higher alkylene oxides (3-12). This chapter is concerned with the ring-opening polymerization of 1,2- or vicinal epoxides to produce linear, or other controlled-structure, polyethers.
Basic Chemical Hazards to Human Health and Safety — I
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
Epoxides are extremely nucleophilic and chemical reactive. Many are carcinogens. Epoxide hydrolases detoxify epoxides. Amines, R–NH2, are oxidized to aldehydes and acids and conjugated to hydrophilic derivatives. Industrial nitro-derivatives, R-NO2, are reduced by hydroxylation. Aromatic hydrocarbons, halogenated aromatic hydrocarbons, and polycyclic hydrocarbons are detoxified by reaction with acetyl mercapturic acid, –SCH2CHCOOH. Inorganic and organic cyanides are neutralized by producing thiocyanate, RCNS. Glycine, –NHCH2COOH, metabolizes aromatic acids, aromatic-aliphatic acids, furane carboxylic acids, thiophene carboxylic acids, and polycyclic carboxylic acids (the Bile acids). Primary, secondary, and tertiary aliphatic and aromatic hydroxyl compounds are metabolized by glucuronate. Hydrazine derivatives are neutralized by glucose hydrazone.
Ethylene oxide review: characterization of total exposure via endogenous and exogenous pathways and their implications to risk assessment and risk management
Published in Journal of Toxicology and Environmental Health, Part B, 2021
CR Kirman, AA Li, PJ Sheehan, JS Bus, RC Lewis, SM Hays
Ethylene oxide is a reactive epoxide that is used in the manufacture of chemicals including ethylene glycol, glycol ethers, ethanolamines, ethoxylates and acrylonitrile and in the sterilization of materials such as foods, spices, and medical equipment. For decades, ethylene oxide was recognized as an animal carcinogen based upon observations of increased tumor rates in highly exposed mice and rats (Lynch et al. 1984; NTP, 1987; Snellings, Weil, and Maronpot 1984). The results of epidemiology studies, however, have been inconclusive. Increases in certain types of cancers were reported in a large study of sterilant workers (2004; Steenland et al. 2003); but these elevations were not seen consistently in other studies, including in a more heavily exposed cohort of chemical workers, followed over an extended time period (Marsh et al. 2019; Swaen et al. 2009). USEPA (2016) reassessed the cancer potency of ethylene oxide on its IRIS database resulting in the derivation of a unit risk value (a quantitative estimate of cancer potency) that is approximately 50-fold higher (i.e. more potent) than its preceding value. This large change in cancer potency estimated for ethylene oxide has initiated changes in its regulation such as the amount that can be released from facilities that produce or use ethylene oxide and the level of exposure considered acceptable. This has also resulted in enhanced public attention and concern over the potential adverse health effects associated with exposures at or near facilities that use ethylene oxide (Hogue 2019; Olaguer et al. 2019).
Schiff base complexes of Mo(VI) immobilized on functionalized graphene oxide nano-sheets for the catalytic epoxidation of alkenes
Published in Journal of Coordination Chemistry, 2019
Behnam Rezazadeh, Ali Reza Pourali, Alireza Banaei, Hossein Behniafar
Catalytic epoxidation of alkenes is of interest for the synthesis of fine chemicals. Because of their versatility as intermediates, epoxies have great value in chemical technology and synthetic organic chemistry [1]. Epoxides react to provide industrially important products such as antistatic agents, detergents, corrosion protection agents, surfactants, textiles, lubricating oils and cosmetics [2]. Large epoxides are fine chemicals with interesting chemical properties, e.g. cyclooctene oxides are extensively used in the manufacturing of pesticides, pharmaceuticals and polyesters [3]. Mo(VI) Schiff base complexes have been used as oxidation catalysts for organic substrates, because Mo(VI) complexes offer advantages such as environmental, economic and commercially available [4]. The fundamental role of molybdenum-based catalysts for production of both fine chemicals and bulk chemicals has increased attention toward this metal [5]. Dioxomolybdenum(VI) complexes of tetradentate Schiff bases [6], dimethyldioxo Mo(VI) diazabutadiene and dichloro were reported as active epoxidation catalysts [7].
Carbon capture and utilization technologies: a literature review and recent advances
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Francisco M. Baena-Moreno, Mónica Rodríguez-Galán, Fernando Vega, Bernabé Alonso-Fariñas, Luis F. Vilches Arenas, Benito Navarrete
The production of cyclic carbonates from CO2 synthesis is a well-established field. One of the most investigated reactions in this field is the addition of CO2 to epoxides which has also been used on an industrial scale for the manufacture of cyclic carbonates and polycarbonates (PC) (Martín, Fiorani, and Kleij 2015). For the reaction of epoxides with CO2, catalysts have been developed based on alkali metal salts, metal oxides, transition metal complexes, organic bases, and ionic liquids. Studies are still emerging that raise other alternative procurement systems, such as, for example, the use of proteins for the catalysis of this reaction. It was demonstrated that amino acids can become a reaction catalyst for cycloaddition of CO2 with epoxides. Relatively adverse conditions, more than 6 MPa of CO2 at 130ºC for 48 h, were necessary to obtain satisfactory results from the use of amino acids (Saptal and Bhanage 2017). Even so, when combining alkaline metal salts with amino acids, excellent results were reported, reaching a propylene oxide conversion of 99% after one hour of operation at a temperature of 120 ºC and 2 MPa of CO2 (Yang et al. 2014).