Fate and Potential Environmental Effects of Methylenediphenyl Diisocyanate and Toluene Diisocyanate Released into the Atmosphere

Tury, Bernard; Pemberton, Denis; Bailey, Robert E.

doi:10.1080/10473289.2003.10466120

Cited by 10 publications

(8 citation statements)

References 11 publications

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“…A worker suspected of having isocyanateinduced asthma/sensitization will exhibit the traditional symptoms of acute airway obstruction, e.g., coughing, wheezing, shortness of breath, tightness in the chest, and nocturnal awakening. An isocyanate-exposed worker may first develop an asthmatic condition (i.e., become sensitized) after a single (acute) exposure, but sensitization usually takes a few months to several years of exposure (NIOSH 1994;Roemmelt and Fruhmann 1994;Tury et al 2003). Dimension of factory (m 3 ) 0 Forward (criterion: probability-of-F-to enter = .050) 3…”

Section: Introductionmentioning

confidence: 99%

“…These compounds are widely used in surface coatings, polyurethane foams, adhesives, resins, elastomers, binders, and sealants. In general, the types of exposures encountered during the use of isocyanates (i.e., monomers, prepolymers, polyisocyanates, and oligomers) in the workplace are related to the vapor pressures of the individual compounds (Bello et al 2002;Tury et al 2003). Isocyanates exist in many different physical forms in the workplace.…”

Section: Introductionmentioning

confidence: 99%

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Indoor air pollution evaluation with emphasize on HDI and biological assessment of HDA in the polyurethane factories

Mirmohammadi

Ibrahim

Ahmad

et al. 2009

Environ Monit Assess

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Today, many raw materials used in factories may have a dangerous effect on the physiological system of workers. One of them which is widely used in the polyurethane factories is diisocyanates. These compounds are widely used in surface coatings, polyurethane foams, adhesives, resins, elastomers, binders, and sealants. Exposure to diisocyanates causes irritation to the skin, mucous membranes, eyes, and respiratory tract. Hexamethylene diamine (HDA) is metabolite of hexamethylene diisocyanate (HDI). It is an excretory material by worker's urine who is exposed to HDI. Around 100 air samples were collected from five defined factories by midget impinger which contained dimethyl sulfoxide absorbent as a solvent and tryptamine as reagent. Samples were analyzed by high-performance liquid chromatography with EC\UV detector using NIOSH 5522 method of sampling. Also, 50 urine samples collected from workers were also analyzed using William's biological analysis method. The concentration of HDI into all air samples were more than 88 microg/m(3), and they have shown high concentration of pollutant in the workplaces in comparison with NIOSH standard, and all of the workers' urine were contaminated by HDA. The correlation and regression test were used to obtain statistical model for HDI and HDA, which is useful for the prediction of diisocyanates pollution situation in the polyurethane factories.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Indoor air pollution evaluation with emphasize on HDI and biological assessment of HDA in the polyurethane factories

Mirmohammadi

Ibrahim

Ahmad

et al. 2009

Environ Monit Assess

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“…Emissions of DII into the atmosphere mainly originate from workplace exhaust ventilation of polyurethane manufacturing facilities (e.g., flexible foam or composite wood products). Atmospheric DII concentrations in the vicinity of emission sources are estimated to be in the parts-per-trillion range. , In the absence of liquid water (e.g., in the form of clouds, fog, rain), homogeneous hydrolysis of DII in the atmosphere was shown to be a slow process . The same holds for direct photolysis, so that oxidation by OH radicals is expected to be the most prevalent gas-phase route of atmospheric degradation of DII …”

Section: Introductionmentioning

confidence: 99%

Reaction of OH with Aliphatic and Aromatic Isocyanates

Welz

Pfeifle

Plehiers³

et al. 2022

J. Phys. Chem. A

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Isocyanates are highly relevant industrial intermediates for polyurethane production. In this work, we used quantum chemistry and transition state theory (TST) to investigate the gas-phase reaction of isocyanates with the OH radical, which is likely one of the most significant chemical sinks for these compounds in the troposphere. para-Tolyl-isocyanate (p-tolyl-NCO) was chosen as a proxy substance for the large-volume aromatic diisocyanate species toluene diisocyanate and methylene diphenyl diisocyanate. Besides p-tolyl-NCO + OH, the model reactions CH3NCO + OH, H2CCHNCO + OH, C6H5-NCO + OH, C6H5-CH3 + OH, and C6H6 + OH have been studied as well to analyze various substituent effects and to allow for comparison with literature. Quantum chemical computations at the CCSD(T)/cc-pV(T,Q → ∞)Z//M06-2X/def2-TZVP level were used as the basis for tunneling-corrected canonical TST calculations. For CH3NCO + OH, H abstraction by OH at the methyl group is the main reaction channel according to our calculations and predicted to be four orders of magnitude faster than OH addition at the NCO group. The calculated rate coefficient (8.8 × 10–14 cm3 molecule–1 s–1) at 298 K is in good agreement with experimental data from the literature. Likewise, for aromatic isocyanates, OH attack at the isocyanate group was found to be only a minor pathway compared to addition to the aromatic ring. In the OH + p-tolyl-NCO reaction, OH addition at the ortho-position relative to the NCO group has been identified as the main initial reaction channel (branching fraction: 53.2%), with smaller but significant branching fractions for the H abstraction at the methyl group (9.6%) as well as the other ring addition reactions (ipso: 2.3%, meta: 24.5%, para: 10.5%, all relative to the NCO group). By comparing OH addition to the aromatic ring in p-tolyl-NCO with the respective ring addition reactions of phenyl isocyanate and toluene, the site-selective reactivity trends observed for ring addition in the OH + p-tolyl-NCO could be rationalized by a dominating positive mesomeric effect of the NCO group and a positive electron-donating (inductive) effect of the CH3 group. Except for the OH ring adduct formed from OH addition in ipso-position to the NCO group, we estimate the first-generation radical intermediates in the OH + p-tolyl-NCO reaction to have sufficiently long lifetimes to react with O2 under atmospheric conditions and undergo typical oxidative reaction cascades like those known for benzene or toluene.

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“…It can enter a soil and water when toluene-containing products are placed in landfills or waste disposal sites (B. Tury, 2003).…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study on the Toluene Degrading Bacteria Isolated From Polluted Environments

Sumathy¹

2017

WJPR

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Humans are primarily exposed to various types of Pollutants and one such pollutant is Toluene. It is moderately toxic when ingested or inhaled and slightly hazardous when absorbed through skin. Toluene can enter human body from the air, water or soil. When toluene is inhaled, it is directly taken into the blood from the lungs. When toluene is ingested, it is absorbed from the GI tract into the bloodstream. Small amount of toluene accumulates in fat tissue with daily exposure and majority of toluene is removed from the body within a day. Toluene leaves the body unchanged during respiration and excretion or it is converted into a less harmful chemical such as hippuric acid.Bioremediation is the best practice of using living organisms to detoxify the polluted environment. There are three different types of bioremediation namely (a) Microbial bioremediation, (b) Phytoremediation and (c) Mycoremediation. The process of using microbes to degrade environmental contaminants to non harmful or less harmful products is termed as microbial biodegradation which can occur aerobically or anaerobically.Aerobic degradation occurs when the pollutant is oxidised using oxygen, nitrogen, iron, sulphate and manganese by the microbes and the pollutant acts as electron donor. Anaerobic degradation occurs when the pollutant is reduced by the microbes. The oxidative microbes degrade toluene via hydroxylation of the aromatic ring to a mixture of catechols and cresols.The present research work is a Comparative study of bacteria isolated from polluted environments that are capable of degrading toluene.

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Fate and Potential Environmental Effects of Methylenediphenyl Diisocyanate and Toluene Diisocyanate Released into the Atmosphere

Cited by 10 publications

References 11 publications

Indoor air pollution evaluation with emphasize on HDI and biological assessment of HDA in the polyurethane factories

Indoor air pollution evaluation with emphasize on HDI and biological assessment of HDA in the polyurethane factories

Reaction of OH with Aliphatic and Aromatic Isocyanates

A Comparative Study on the Toluene Degrading Bacteria Isolated From Polluted Environments

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