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Advanced manufacturing and high-quality materials
Published in Natalia Yakovleva, Edmund Nickless, Routledge Handbook of the Extractive Industries and Sustainable Development, 2022
Kazuyo Matsubae, Eiji Yamasue, Hisao Ohtake
The elemental phosphorus produced by the process explained above is used as a starting material for the manufacture of various final products. For instance, elemental phosphorus is oxidized to produce thermal phosphoric acid which is used for the manufacture of high-quality phosphate salts and phosphate esters. Elemental phosphorus is also reacted with chlorine to form phosphorus chlorides, such as phosphorus trichloride, phosphorus pentachloride, and phosphorus oxychloride. Further, the allotropic modification of elemental phosphorus produces red phosphorus. These products are used as food additives, in the production of flame retardants, as plasticizers, as electrolytes for lithium secondary batteries, and as agents for plating, etching, and surface treatments.
Flame Retardance of Fabrics
Published in Menachem Lewin, Stephen B. Sello, Handbook of Fiber Science and Technology: Chemical Processing of Fibers and Fabrics, 2018
The most important FR chemical used extensively by the industry until 1977 was TBPP. It is prepared by addition of bromine to allyl alcohol to produce 2,3-dibromopropanol, which, upon reaction with phosphorus oxychloride, yields TBPP. TBPP is a dense, colorless, fairly viscous liquid, insoluble in water, stable at ~200°C, and very stable to hydrolysis. TBPP is padded on the fabric which is then dried at 110°C for 1 min, then dry heat-thermosoled for 1 min at 200–220°C. TBPP is absorbed into the fiber and stands up against repeated home launderings; 6–8 weight % add-on of TBPP to 100% woven light-weight PET fabrics is needed for these fabrics to pass the DOC FF-3-71 test. However, it is difficult to retain more than 4–5% TBPP (by weight of the fiber) in the fiber permanently [392]. TBPP can also be exhausted onto the fabric in an operation similar to dyeing. Emulsions and emusifiable concentrates of TBPP have been marketed for a number of years. It has been shown that the retention of TBPP in the PET can be increased significantly if the PET has been pretreated by the “porofication” process [393–395].
Pyrometallurgy
Published in C. K. Gupta, Extractive Metallurgy of Molybdenum, 2017
In addition to chlorine, a modified approach involving the use of chlorine-oxygen mixture appears advantageous in relation to the chlorination process. This approach is especially important in situations where the metal chloride formed by chlorinating with elemental chlorine is nonvolatile and insoluble in water. Processing of chromite for recovering chromium by anhydrous chlorination can be mentioned as an example in this context. Chlorination of chromite with chlorine alone yields chromium chloride. Since this compound is nonvolatile at the temperature of chlorination and is not water soluble, the recovery of chromium from the chlorinated product is feasible. However, upon chlorination with chlorine-oxygen mixtures, chromium oxychloride forms. This oxychloride, being highly volatile, is easily removed from the reaction sites. The volatilized oxychloride can be collected in condensers attached to the chlorinating reactor. Processing of chromite via the oxychlorination process appears to be a very interesting alternative to the conventionally used processes.
Minreview: Recent advances in the development of gaseous and dissolved oxygen sensors
Published in Instrumentation Science & Technology, 2019
Q. Wang, Jia-Ming Zhang, Shuai Li
In 2013, a low-cost dissolved oxygen sensor based oxychloride was developed by Hsu and Selvaganapathy.[48] The platinum sensing electrode was replaced with chlorinated hemoglobin as a low-cost alternative to the oxygen reduction. Two silicone rubber polydimethylsiloxane (PDMS) functionalized with polyethylene glycol (PEG) was used as the anti-bioadhesive gas permeable membrane to provide selectivity with an increased lifetime. This dissolved oxygen sensor had a sensitivity of 20.7 (μA/cm2)/(mg/L) in the concentration range of 2–7 mg/L. In addition, common disturbances, such as phosphates and nitrates, showed a little effect on dissolved oxygen detection. Under accelerated biofouling conditions, polyethylene glycol (PEG) functionalization of polydimethylsiloxane membrane reduced bio-fouling and increased the lifetime by a factor of 20.
Comprehensive review on catalytic degradation of Cl-VOCs under the practical application conditions
Published in Critical Reviews in Environmental Science and Technology, 2022
Fawei Lin, Li Xiang, Zhiman Zhang, Na Li, BeiBei Yan, Chi He, Zhengping Hao, Guanyi Chen
Chlorination produces chlorinated aromatics with higher chlorine substituents. Therefore, further destruction after electrophilic substitution can be regarded as the degradation process of DCB (Sun et al., 2016). Dichlorobenzene transformed into quinine species, then into chlorinated acetates and chloro-maleates, and finally polychlorinated chain hydrocarbons (attacking by dissociated Cl species) or CO2/H2O (Taralunga et al., 2005; Wang et al., 2015b). Tang et al. proposed a DCB degradation mechanism over CeMn catalysts (Yang et al., 2019d). After adsorption, hydroxyl nearby oxygen vacancies of CeO2 provided hydrogen to combine with the dissociated Cl species forming HCl. The electron-rich Mn–O–Ce weakened Cl adsorption. A simple mechanism for DCB degradation over CeMn/TiO2-SiO2 catalyst with both redox and acid sites was proposed (Zhao et al., 2018). Adsorption on the acid sites via nucleophilic substitution, oxidation by active oxygen species (Wang et al., 2015c; Weng et al., 2017), and further oxidation into CO2, H2O, Cl2, and HCl occurs in sequence. Density functional theory calculations demonstrated that oxychloride species are generated from dissociated oxygen species and Cl species, that is oxychlorination (Podkolzin et al., 2007). Zhu et al. pointed out that more chlorine substituents resulted in higher activation energy, approximately 62.5 kJ/mol for CB and 86.1 kJ/mol for TCB over V2O5/TiO2 (Wang et al., 2015a). More chlorine substituents exhibited negative effect on degradation owing to the electron-withdrawal effect. However, polychlorinated benzenes were more active in nucleophilic substitution, which was considered as kinetically significant step (Wang et al., 2015c).