Effects of Toluene Vapor

The toxic threshold limit value as reported by Sax (Ref 3) ia ( pm in air or 750mg/m of air, and by Plunkett (Ref 8) is lOOppm and 375mg/m. Acute poisoning from the use of toluene is the result of a small amount of benz in commercial (coal-tar) derived toluene. Table 1 presents the effects of toluene vapor (Ref 4). Plunkett (Ref 8) reports that prolonged exposure to toluene vapor can result in permanent central nervous system changes such as cerebellar degeneration, tremulousness, ataxia, emotional lability and EEC changes... 

Shelton RL, Grant KL (2001) Effects of naltrexone on R1 15-4513 on multiple schedule of ethanol and tang self-administration. Clin Exp Res 25 1576-1585 Shelton KL, Nicholson K (2013) Benzodiazepine-like discriminative stimulus effects of toluene vapor. Eur J Pharmacol 720 131-137... 

It is important to note the effect of toluene vapor on the Vis/UV spectrum of a thin film of poly(3-hexylthiophene) spun from a chloroform solution on to a microscope slide (8, 49). A small piece of the slide together with attached film was placed in a cuvette in the spectrometer with air in the reference cuvette and its spectrum was recorded. The film was removed, a few drops of toluene were placed in both cuvettes and the film was carefully suspended in a cuvette and its spectrum was again measured after five minutes. There was no change in the spectrum after an additional 20 minutes in the cuvette. The film was removed and permitted to remain in the air for five minutes. As can be seen from Figure 20, toluene vapor results in a partly reversible effect on the Vis/UV spectrum of the poly(3-hexylthiophene). We have found that gas desorption is frequently slower than gas adsorption in systems of this type we have not yet determined whether a longer period in air would result in greater reversibility. 

Figure 20. Effect of toluene vapor ( 25 C 26 torr 35,OOOppm) on VisAJV spectrum of a thin regioregular poly(3-hexylthiophene) fflhn spun from chloroform solution. Reproduced with permission from reference 50. Copyright 1997 Society of Plastics Engineers.

Studies of the intoxicating effects of toluene showed that the inhalation of its vapor at a concentration of 200 ppm was associated with the development of mild-to-moderate intoxication, characterized by sedation, paresthesias, and hyporeflexia. Toluene vapor concentrations of 600-800 ppm induced a confusional state, whereas greater concentrations produced an intense euphoria (Benignus 1981 Press and Done 1967). In humans, plasma concentrations of toluene of 10-100 pM have been reported to be intoxicating these concentrations are close to the intoxicating concentrations of alcohol and in-halational anesthetics (Miller 1985). 

Himnan DJ Tolerance and reverse tolerance to toluene inhalation effects on open-field behavior. Pharmacol Biochem Behav 21 625-631, 1984 Hinman DJ Biphasic dose-response relationship for effects of toluene inhalation on locomotor activity. Pharmacol Biochem Behav 26 65-69, 1987 Hormes JT, Filley CM, Rosenberg NL Neurologic sequelae of chronic solvent vapor abuse. Neurology 36 698—702, 1986... 

Figure 8.6 shows the effect of water vapor on the formation of C02 and BA for the toluene oxidation. The concentration of C02 increased linearly with the increase in relative humidity. The yield at 60% relative humidity was greater by one order than that in the dry condition. It has been pointed out that the amount of 02 adsorbed under photoillumination is proportional to that of hydroxyl groups (OH-) un the Ti02 surface. The phenomenon has been explained by the following reactions ... 

Pleil, J.D., L.B. Smith, and S.D. Zelnick. 2000. Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases. Environ. Health Perspect. 108(3) 183-192. Pryor, G.T., and C.S. Rebert. 1992. Interactive effects of toluene and hexane on behavior and neurophysiologic responses in Fischer-344 rats. Neurotoxicology 13(l) 225-234. 

Flg.8 (a) Time response of Au/PDMS sensing film to Fig.8 (b) Effect of concentration of Toluene vapors on Toluene vapors at a concentration of lOOppm Au/PDMS sensing film. 

The effect of a noncondensable gas in the system with a condensable vapor is to significandy reduce the condensing side film coefficient. Henderson and Marcello present data to illustrate the effect. Figures 10-85, 10-86, and 10-86A present the effect of AT with a steam-air system and toluene-... 

For the evaluation of the response of the sensor, we selected several vapors of different polarity. The vapors included water (H20), acetonitrile (ACN), toluene, and dichloromethane (DCM). Solvent polarity and refractive index of tested vapors are listed in Table 4.346 47. The spectral range for the evaluation of the vapor responses of the colloidal crystal film was selected as 700 995 nm, which covered only the fundamental Bragg diffraction peak on the (111) planes of the colloidal crystal film to further reduce effects from possible stacking defects in the film as suggested in the literature44. 

The polar and nonpolar vapors at different concentrations were separated in PCA space. The best selectivity was obtained between toluene and DCM vapors at low concentrations, while water and ACN vapors were almost unresolved. At the highest tested vapor concentration of 0.1 P/Po, toluene and DCM vapors likely induced film swelling that resulted in the decrease in the vapor response selectivity. Overall, two first PCs described more than 98% of total variance in the spectral data with PC2 contribution of only 5% from the original spectral data. This relatively small contribution of PC2 was likely due to the film-swelling effects at high vapor concentration. 

In our previous paper we have reported that silica MCM-41 exhibits a large amount of reversible adsorption, high thermal and hydrothermal stabilities, and little catalytic acidity and is an excellent adsorbent in PSA process for recovery of 2-propanol and toluene vapors [1]. Here we present the results of PSA of butanone on silica MCM-41 and discuss the effect of pretreatment temperatures on adsorption properties of MCM-41. 

Figure 7.17. Effect of salt content of water on vapor distribution of toluene. Successive equilibration of toluene (equal starting concentrations) between helium and water of differing salt content.

Figure 13.23. Examples of vapor-liquid equilibria in presence of solvents, (a) Mixture of-octane and toluene in the presence of phenol, (b) Mixtures of chloroform and acetone in the presence of methylisobutylketone. The mole fraction of solvent is indicated, (c) Mixture of ethanol and water (a) without additive (b) with 10gCaCl2 in 100 mL of mix. (d) Mixture of acetone and methanol (a) in 2.3Af CaCl2 ip) salt-free, (e) Effect of solvent concentration on the activity coefficients and relative volatility of an equimolal mixture of acetone and water (Carlson and Stewart, in Weissbergers Technique of Organic Chemistry IV, Distillation, 1965). (f) Relative volatilities in the presence of acetonitrile. Compositions of hydrocarbons in liquid phase on solvent-free basis (1) 0.76 isopentane + 0.24 isoprene (2) 0.24 iC5 + 0.76 IP (3) 0.5 iC5 + 0.5 2-methylbutene-2 (4) 0.25-0.76 2MB2 + 0.75-0.24 IP [Ogorodnikov et al., Zh. Prikl. Kh. 34, 1096-1102 (1961)].

Vapor-phase oxidation of toluene to benzaldehyde was studied with various Mo-, U—, and Sb-based mixed-oxide catalysts. The selectivity to benzaldehyde fell with increasing the toluene conversion. The best performances were obtained with Mo-P and U-Mo oxide catalysts the one-pass yield of benzaldehyde reached 40 mol% with a selectivity of about 60 mol%. The catalytic activity of the U-Mo oxides was more stable than that of the Mo-P oxides. The effects of the reaction variables on both the rate and selectivity were also studied. 

Cymene or isopropyltoluene is produced via alkylation of toluene with propylene. Cymene is an important intermediate in the production of cresol, and it is also used as an industrial solvent. Again, for both environmental and economic reasons, the use of zeolitic materials for this conversion has been studied. For example, Flockhart et al. have used zeolite Y to effect this reaction (7). They observed that the state of the zeolite, including its degree of ion-exchange and the temperature at which it was calcined, strongly affected the distribution of cymene isomers obtained. In order to enhance the selectivity to para-cymene, the direct precursor to para-cresol, various studies have focused on the use of surface modified zeolites, for example, ZSM-5 materials, including those produced by chemical vapor deposition (CVD) of silicate esters. These species serve to reduce surface acidity and change limit diffusion within the crystal. 

A liquid mixture of benzene and toluene containing 50.0 wt% benzene at 90 C and pressure Po is fed at a rale of 32.5 m /h into a flash evaporator, a heated tank maintained at a pressure P,ank Po-When the feed is exposed to the reduced pressure in this unit, a portion of it evaporates. The liquid and vapor product streams are in equilibrium at 75 C and P,ank- liquid product contains 43.9 mole% benzene. When carrying out the requested calculations, assume volume additivity of liquid benzene and toluene, use Raoult s law and the Antoine equation where necessary, and neglect the effect of pressure on enthalpy. 

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