Benzene tire

PAHs are believed to be a major class of carbon-bearing molecules in the interstellar medium 1138], They are found in carbonaceous chondrites tliat have fallen to Earth (see section 4.2.1) and in interplanetary dust particles [28]. Shock and Schulte [139] suggested that amino acids could be syntliesized by aqueous alteration of precursor PAHs in carbonaceous chondrites. We directed attention to shock reaction of PAHs [135,140,141], and conducted shock reactions using benzene, tire simplest aromatic hydrocarbon, as a starting material to simulate possible reactions occurring in interstellar space. Furtliermore, we examined the mechanism of shock reaction on the basis of quantum chemistry and discussed the implication for cosmocheniistiy. 

In the early part of the twentieth century, benzene was used as a universal solvent and degreaser and found widespread use throughout the mbber iadustry iu the manufacture of tires. By the late 1920s, foUowiug reports of deaths due to benzene exposure, it was largely replaced by toluene and ahphatic solvents (131). 

Tlie reaction of 5,6-dithiabicyclo[2.1.1]hexaiie 11a with OXONE led to the corresponding dithiirane 12a, which was, however, stable only in solution (Amax at 442 nm in CH2CI2). Treatment of the reaction mixture containing 12a with MCPBA gave the dithiirane 1-oxide 13a (8%) (95TL1867). Tire introduction of electron-withdrawing substituents on the benzene rings provided the dithiirane oxide 13b in a better yield (21%). 

Two types of networks were prepared (i) randomly crosslinked polybutadiene, and (ii) model urethane networks, (a) polybutadiene based, and (b) poly(e-caprolactone) based. The randomly crosslinked networks were prepared from polybutadiene (Duragen 1203 obtained from General Tire and Rubber Co.) crosslinked with di-cumyl peroxide. Specifications of the as obtained polybutadiene are given in Table I. Polybutadiene was purified by dissolving in benzene and precipitating in methanol. Precipitated polybutadiene was redissolved in benzene. Seven different weights of dicumyl... 

Susten AS et al Percutaneous penetration of benzene in hairless mice An estimate of dermal absorption during tire building operations. 7/wii 7 323-335, 1985... 

Researchers at Lehigh University have investigated the ability of ground tire rubber to sorb organic compounds such as benzene, toluene, ethylbenzene, and xylene (BTEX) to determine the feasibility of using the rubber as the sorbent media in reactive permeable barrier systems. Thus far, no field-scale work has been performed on this technology. Both batch and packed-bed column tests have been conducted. All information is from the researchers and has not been independently verified. 

Source Oil spills. Tire basic organic chemicals industry is responsible for 82.53 t/yr of benzene, toluene, ethyl benzene, and xylene (BTEX) direct releases into water. 

Pyrolysis - [MANGANESE COMPOUNDS] (Vol 15) -in batteries [BATTERIES - PRIMARY CELLS] (Vol 3) -of benzene [BENZENE] (Vol 4) -of esters [ESTERS, ORGANIC] (Vol 9) -of lignite [LIGNITE AND BROWN COAL] (Vol 15) -of scrap tires [RECYCLING - RUBBER] (Vol 21)... 

Use of fully deuterated benzene gave ku/ko = 1. These data suggest diat the nitrating agent attacks the benzene ring in tire rate-determining step, but C-H... 

In theory, almost any polymer can be used as a reinforcement in an advanced composite. By far the most common polymer fiber, however, is aramid, better known by its trade name, Kevlar. Developed originally for use in belted radial tires, aramid is an aromatic polyamide in which benzene fragments (C6H4) alternate with peptide groups (NHC = Q) in forming a polymeric structure ... 

Naphthas are used in the rubber industry for dampening the play and tread stocks of automobile tires during manufacture to obtain better adhesion between the units of the tire. They are also consumed extensively in making rubber cements (adhesives) or are employed in the fabrication of rubberized cloth, hot-water bottles, bathing caps, gloves, overshoes, and toys. These cements are solutions of rubber and were formerly made with benzene, but petroleum naphtha is now preferred because of its less toxic character. 

So, by adopting a varying reflux ratio, the mole fraction of the benzene in tire receiver was maintained constant at 0,95, higher than in either of the two cases... 

Chronic exposure to benzene and toluene was studied in 121 workers exposed to benzene for 2-9 years (Kahn and Muzyka 1973). The air concentration of benzene between 1962 and 1965 was 6-15.6 ppm (20-50 mg/m3), while the toluene vapors did not exceed the 5 mg/m3 level. Subsequently (the authors do not specify when), the air levels of both benzene and toluene have not exceeded the 5 mg/m3 level. Seventy-four of the examined workers complained of frequent headaches (usually at the end of the work day), became tired easily, had difficulties sleeping, and complained of memory loss. The limitations of this study are that workers were exposed to both benzene and toluene and that the precise dose and duration of exposure are not known. 

Based on an observational study of workers in a tire factory, it was estimated that a worker exposed to benzene as a result of direct skin contact with petroleum naphtha containing 0.5% benzene could absorb 4-8 mg of benzene per day through intact skin (Susten et al. 1985). This amount absorbed was compared with an estimated 14 mg of benzene absorbed as a result of inhalation of 1 ppm for an 8-hour day. The estimate for dermal absorption is exaggerated since in many facilities the concentration of benzene in rubber solvents such as petroleum naphtha is less than 0.5% and may be as low as 0.09%. 

Several in vivo and in vitro studies conclusively demonstrate that benzene can be absorbed through human skin (Blank and McAuliffe 1985 Franz 1984 Susten et al. 1985 Tsuruta 1989). In general, skin absorption is considered a minor source of concern in the occupational environment as it occurs at a much lower rate and extent compared with benzene absorption through the respiratory system (OSHA 1989). However, benzene absorption through the skin as a result of benzene contamination in rubber solvents is a major route of exposure in tire building operations (Susten et al. 1985). Benzene is an irritant to the skin and, by defatting the keratin layer, may cause erythema, vesiculation, and dry and scaly dermatitis... 

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