Methyl Isocyanate Research Articles

Characterization of US population levels of urinary methylcarbamoyl mercapturic acid, a metabolite of N,N-dimethylformamide and methyl isocyanate, in the National Health and Nutrition Examination Survey (NHANES) 2005-2006 and 2011-2016.

Methylcarbamoyl mercapturic acid (MCAMA, N-acetyl-S-(N-methylcarbamoyl)-L-cysteine) is a urinary metabolite of N,N-dimethylformamide and methyl isocyanate, which are volatile organic compounds that are harmful to humans. N,N-dimethylformamide exposure causes liver damage, and methyl isocyanate inhalation damages the lining of the respiratory tract, which can increase risk of chronic obstructive pulmonary disease and asthma. This study characterizes urinary MCAMA levels in the US population and explores associations of MCAMA concentrations with select demographic and environmental factors. We used liquid chromatography tandem mass spectrometry to measure MCAMA in urine collected from study participants ≥ 12 years old (N = 8272) as part of the National Health and Nutrition Examination Survey 2005-2006 and 2011-2016. We produced multiple regression models with MCAMA concentrations as the dependent variable and sex, age, fasting time, race/ethnicity, diet, and cigarette smoking as independent variables. Cigarette smokers and nonsmokers had median urinary MCAMA concentrations of 517 μg/g creatinine and 127 μg/g creatinine, respectively. Sample-weighted multiple regression analysis showed that MCAMA was positively associated with serum cotinine (p < 0.0001). Compared to non-exposed participants (serum cotinine ≤ 0.015 ng/mL), presumptive exposure to second-hand tobacco smoke (serum cotinine > 0.015-≤ 10 ng/mL and 0 cigarettes smoked per day) was associated with 20% higher MCAMA (p < 0.0001). Additionally, smoking 1-10 cigarettes per day was associated with 261% higher MCAMA (p < 0.0001), smoking 11-20 cigarettes per day was associated with 357% higher MCAMA (p < 0.0001), and smoking > 20 cigarettes per day was associated with 416% higher MCAMA (p < 0.0001). These findings underscore the strong association of tobacco smoke exposure with urinary MCAMA biomarker levels.

Development of a Scalable and Sublimation-Free Route to MTAD.

The cyclic azodicarbonyl 4-methyl-1,2,4-triazoline-3,5-dione (MTAD) is a versatile and powerful reagent used mainly in cycloaddition chemistry. Though known for more than 50 years, its unsafe preparation, as well as purification by sublimation, hampered its widespread applicability on a larger scale. Herein we report a scalable and safe route to MTAD, which avoids the generation of methyl isocyanate. Moreover, we demonstrate that sublimation can be circumvented by the application of judicious oxidation conditions, followed by simple filtration. Overall, up to 25 g of MTAD was prepared in a single batch from commercial starting materials in three steps, with recrystallization serving as the only purification in the sequence. When employed in dearomative methodologies, the MTAD obtained by this protocol displayed synthetic efficiency equivalent to that of MTAD purified by sublimation.

A facile method to control the phase behavior of hydroxypropyl cellulose

We report a facile chemical method to convert the hydroxyl groups of hydroxypropyl cellulose (HPC) into carbamates. It was achieved by the reaction of HPC with N-methyl carbamoylimidazole, which is a safe and easy to handle replacement for the particularly hazardous reagent methyl isocyanate. Using a series of HPC with a range of molar substitution of hydroxypropyl groups, we synthesized HPC methylcarbamates showing lower critical solution temperature (LCST) in the range between 94 and 15 °C. A linear dependence of LCST versus methylcarbamate degree of substitution is observed. The lower the initial hydroxypropyl content of HPC, the greater the effect of methylcarbamate on the LCST. Surface tension study showed that methylcarbamate modification has an insignificant effect on the hydrophilic-hydrophobic balance of the macromolecules below LCST unless the molecular substitution of hydroxypropyl groups is so low (0.8) that the native cellulose OH groups can react with N-methyl carbamoylimidazole.

Quasi-symmetry effects in the threshold photoelectron spectrum of methyl isocyanate.

The vacuum-ultraviolet threshold photoelectron spectrum of methyl isocyanate CH3NCO has been recorded from 10.4 eV to 12 eV using synchrotron radiation and a coincidence technique allowing for a mass-discrimination of the photoelectron signal. A significant improvement is achieved over previous investigations as this experimental setup leads to a much more resolved spectrum. Ten sharp peaks and a broad feature spanning 1.2 eV were recorded. This spectrum consists of X̃+ 2A″←X̃ 1A' and Ã+ 2A'←X̃ 1A' ionizing transitions. For the former, the adiabatic ionization energy was determined experimentally to be 10.596(6) eV; for the latter, its value was estimated to be 10.759(50) eV. Seven sharp peaks could be assigned to vibrational modes of the cation X̃+ 2A″ and neutral X̃ 1A' ground electronic states involving only the NCO group atoms. Theoretical modeling of the threshold photoelectron spectrum has proven difficult as methyl isocyanate is a non-rigid molecule displaying large amplitude internal rotation of the methyl group and ∠CNC bending mode, leading to the quasi-symmetry. With the help of ab initio calculations, a theoretical model in which these two large amplitude motions are included in addition to the five small amplitude vibrational modes involving NCO group atoms is proposed. Comparison with the experimental spectrum shows that the broad feature and the strongest peak line positions are well accounted for; their intensities are also fairly well reproduced after adjusting a few parameters.

Atmospheric Fate of Methyl Isocyanate, CH3NCO: OH and Cl Reaction Kinetics and Identification of Formyl Isocyanate, HC(O)NCO

CH3NCO, methyl isocyanate, is a toxic compound that is formed in the atmosphere following the use of agricultural and industrial precursors as well as emission from biomass burning. The atmospheric abundance and chemistry of CH3NCO, however, is presently not sufficiently well characterized to evaluate its overall environmental and health impacts. In this study, rate coefficients for the gas-phase reaction of OH radicals (k1) and Cl-atoms (k2) with CH3NCO were measured using pulsed laser photolysis–laser-induced fluorescence and relative rate methods at 295–375 and 296 K, respectively. We obtained k1(295 K) = 1.36 × 10–13 cm3 molecule–1 s–1 with the temperature dependence given by the Arrhenius expression k1(295–375 K) = 6.11 × 10–12 exp(−(1119 ± 62)/T) cm3 molecule–1 s–1. The Cl atom rate coefficient was determined to be k2(296 K) = 5.58 × 10–12 cm3 molecule–1 s–1. k1(295 K) from this study is compared with a previous room temperature measurement and an explanation for the significantly greater literature value, a factor of 26.6, is discussed. As part of this work, the stable end products following the OH radical- and Cl atom-initiated oxidation of CH3NCO were obtained in an environmental chamber reactor with infrared absorption detection. Formyl isocyanate, HC(O)NCO, was identified by comparison with its theoretically calculated infrared absorption spectrum as a major stable end product. A CH3NCO atmospheric degradation mechanism is proposed. In addition, quantitative UV and infrared absorption spectra of CH3NCO are reported.

PREVENTING THE TRANSITION OF CORONA THROUGH SCIENCE &amp; TECHNOLOGY:GLOBALLY INTEGRATED SOCIETY TOWARDS POSITIVE CHANGE

The entire basis of science is technology, technology that facilitates us, it also cautions us how destructive it can be to use it wrongly. Such as Bhopal Gas Tragedy containing leakage of Methyl isocyanate or radiation from Japan’s atomic reactor due to Tsunami, it is an event that the slightest negligence of science or technology can lead to a major tragedy.Covid-19 is one such phenomenon, and it took a while to understand and it convert into form of a serious illness. The Pandemic Disease of the century, which is spreading its infection in the whole world, and is likely to be Seriously thought.

Atmospheric Chemistry of Methyl Isocyanide-An Experimental and Theoretical Study.

The reaction of CH3NC with OH radicals was studied in smog chamber experiments employing PTR-ToF-MS and long-path FTIR detection. The rate coefficient was determined to be kCH3NC+OH = (7.9 ± 0.6) × 10–11 cm3 molecule–1 s–1 at 298 ± 3 K and 1013 ± 10 hPa; methyl isocyanate was the sole observed product of the reaction. The experimental results are supported by CCSD(T*)-F12a/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ quantum chemistry calculations showing the reaction to proceed primarily via electrophilic addition to the isocyanide carbon atom. On the basis of the quantum chemical data, the kinetics of the OH reaction was simulated using a master equation model revealing the rate coefficient to be nearly independent of pressure at tropospheric conditions and having a negative temperature dependence with kOH = 4.2 × 10–11 cm3 molecule–1 s–1 at 298 K. Additional quantum chemistry calculations on the CH3NC reactions with O3 and NO3 show that these reactions are of little importance under atmospheric conditions. The atmospheric fate of methyl isocyanide is discussed.

Identification of Prebiotic Molecules Containing Peptide-like Bonds in a Hot Molecular Core, G10.47+0.03

Abstract After hydrogen, oxygen, and carbon, nitrogen is one of the most chemically active species in the interstellar medium. Nitrogen-bearing molecules are very important as they are actively involved in the formation of biomolecules. Therefore, it is essential to look for nitrogen-bearing species in various astrophysical sources, specifically around high-mass star-forming regions where the evolutionary history is comparatively poorly understood. In this paper, we report on the observation of three potential prebiotic molecules, namely, isocyanic acid (HNCO), formamide (NH2CHO), and methyl isocyanate (CH3NCO), which contain peptide-like bonds (–NH–C(=O)–) in a hot molecular core, G10.47 + 0.03 (hereafter, G10). Along with the identification of these three complex nitrogen-bearing species, we speculate on their spatial distribution in the source and discuss their possible formation pathways under such conditions. A rotational diagram method under local thermodynamic equilibrium has been employed to estimate the excitation temperature and the column density of the observed species. The Markov Chain Monte Carlo method was used to obtain the best-suited physical parameters of G10 as well as line properties of some species. We also determined the hydrogen column density and the optical depth for a different continuum observed in various frequency ranges. Finally, based on these observational results, we have constructed a chemical model to explain the observational findings. We found that HNCO, NH2CHO, and CH3NCO are chemically linked with each other.

Adsorption of methyl isocyanate on M4 (M=Fe, Ni, and Cu) cluster-decorated graphene and vacancy graphene: a DFT-D2 study

Adsorption of a toxic gas, methyl isocyanate (MIC), has been studied on different metal (Fe, Ni, and Cu) cluster-decorated graphene and vacancy graphene. The binding of M4 clusters on vacancy graphene surfaces is higher than on pristine graphene. The magnetic properties of all surfaces have also been studied. MIC is weakly adsorbed on graphene and vacancy graphene, but chemisorbed when graphene surfaces are decorated with metal clusters, with high adsorption energy and large Hirshfeld charge transfer. To further investigate the adsorption, electron density difference, density of states (DOS), and partial density of states (PDOS) before and after adsorption were plotted. The band gap of all the surfaces before and after adsorption of methyl isocyanate has also been calculated.

Alleviation of methyl isocyanate-induced airway obstruction and mortality by tissue plasminogen activator.

Methyl isocyanate (MIC, "Bhopal agent") is a highly reactive, toxic industrial chemical. Inhalation of high levels (500-1000 ppm) of MIC vapor is almost uniformly fatal. No therapeutic interventions other than supportive care have been described that can delay the onset of illness or death due to MIC. Recently, we found that inhalation of MIC caused the appearance of activated tissue factor in circulation with subsequent activation of the coagulation cascade. Herein, we report that MIC exposure (500 ppm for 30 min, nose-only) caused deposition of fibrin-rich casts in the conducting airways resulting in respiratory failure and death within 24 h in a rat model (LC90-100 ). We thus investigated the effect of airway delivery of the fibrinolytic agent tissue plasminogen activator (tPA) on mortality and morbidity in this model. Intratracheal administration of tPA was initiated 11 h post MIC exposure and repeated every 4 h for the duration of the study. Treatment with tPA afforded nearly 60% survival at 24 h post MIC exposure and was associated with decreased airway fibrin casts, stabilization of hypoxemia and respiratory distress, and improved acidosis. This work supports the potential of airway-delivered tPA therapy as a useful countermeasure in stabilizing victims of high-level MIC exposure.

Frequency of micronuclei in population of Bhopal exposed to methyl isocyanate in 1984

Micronuclei represent whole chromosome or large acentric fragments lagging behind the ana-telophasic separation of cell division. However, it progresses towards completion of karyokinesis and eventually gets included in one of the two daughter cells through cytokinesis. The frequency of micronuclei was estimated in 107 subjects exposed to methyl isocyanate (MIC) gas 30-years post-disaster and compared with 35 unexposed subjects of similar socio-cultural background from the same geographical region. Ethical approval and participants’ informed consent were obtained, and quality issues were validated prior to the proposed investigation. Peripheral blood was collected for each participant from their residence and transported to Mumbai for technical processing and cytogenetic analysis. Replicate cultures with 0.5 ml of whole blood were stimulated in 5 ml of serum supplemented RPMI1640 medium and maintained at 37°C for 72 h. The cells were dropped onto chilled slides following standard harvesting schedule, air dried and stained in Giemsa. Microscopic observation of 1000 cells for each subject has recognized lymphocyte cells (MNC) with micronucleus (MN). The ratio of MN and MNC indicated number of micronuclei per micronucleated cell. Statistical analysis revealed exposure related incidences of MN, MNC and MN/MNC, which was significant (p < 0.05) when compared with unexposed population and/or between moderate and severe exposure status (MN) of the population. Age-related MNC-incidence was significant between adult and childhood exposure to MIC gas. The differences of MN-incidences in the three severely exposure-zones (S1, S2, and S7) were significantly higher than the unexposed zones (C14, C16). The incidence of MN was consistent with our earlier study on chromosome aberrations detected in the same population 30-years post-disaster. However, the MN/CA incidences cannot be directly linked to MIC-exposure of 1984 owing to contribution of several confounding factors over 30 years. Nevertheless, the study could be considered as a low-cost tool but useful for estimation of DNA-damage in risk-assessment.

Study of the thermal behavior in oxidative and pyrolysis conditions of some transition metals complexes with Lornoxicam as ligand using the techniques: TG-DSC, DSC, HSM and EGA (TG-FTIR and HSM-MS)

Lornoxicam metal complexes [M(Lor)2(OH2)2]∙nH2O, where M represents the bivalent transition metals (Mn(II) to Zn(II)), Lor is Lornoxicam ligand and n = 2.0 or 2.5 were synthesized. The compounds were characterized by elemental analysis (EA), powder X-ray diffraction (PXRD), infrared spectroscopy (FTIR), simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) under oxidizing and pyrolysis conditions, differential scanning calorimetry (DSC), hot-stage microscopy (HSM) and evolved gas analysis (EGA) by coupled hot-stage microscopy (HSM-MS) and Fourier transform infrared (TG–FTIR). Regardless of the atmosphere, the thermal stability and thermal behavior up to the first two mass loss steps of the anhydrous compound were similar, only differing significantly in the last steps. The main gaseous products released were H2O (dehydration), SO2, CO, CO2, COS, HCN, HNCO, Methyl Isocyanate, and Ethyl Isocyanate. In addition, FTIR data suggest that pyridyl and carboxyl groups are the coordination sites for metal ions and confirm the presence of differing bounded waters.

Altivia to buy Dow’s Institute plant

Dow has agreed to sell its Institute, West Virginia, complex—including its acetone derivatives business—to Altivia for an undisclosed sum. With the acquisition, Altivia will take on the largest North American facility for ketones and carbinols, used primarily as solvents for nitrocellulose and other cellulose ethers and for various resins. “Acquiring this facility and associated technology provides downstream expansion for Altivia’s acetone production capacity and access to global markets for acetone derivatives,” Altivia CEO J. Michael Jusbasche says in a statement. “Additionally, the Institute Industrial Park’s excess capacity of utilities and services provide options to install additional chemical production for a fraction of the cost of alternatives.” The 185-hectare site on the Kanawha River was originally owned by Union Carbide, which operated a methyl isocyanate facility comparable to the plant that exploded in Bhopal, India, in 1984. The sale by Dow, which has owned the site since 2015, marks the fourth

Re-exploring Molecular Complexity with ALMA (ReMoCA): interstellar detection of urea

Context. Urea, NH2C(O)NH2, is a molecule of great importance in organic chemistry and biology. Two searches for urea in the interstellar medium have been reported in the past, but neither were conclusive. Aims. We want to take advantage of the increased sensitivity and angular resolution provided by the Atacama Large Millimeter/submillimeter Array (ALMA) to search for urea toward the hot molecular cores embedded in the high-mass-star-forming region Sgr B2(N). Methods. We used the new spectral line survey named ReMoCA (Re-exploring Molecular Complexity with ALMA) that was performed toward Sgr B2(N) with ALMA in its observing cycle 4 between 84 and 114 GHz. The spectra were analyzed under the local thermodynamic equilibrium approximation. We constructed a full synthetic spectrum that includes all the molecules identified so far. We used new spectroscopic predictions for urea in its vibrational ground state and first vibrationally excited state to search for this complex organic molecule in the ReMoCA data set. We employed the gas-grain chemical kinetics model MAGICKAL to interpret the astronomical observations. Results. We report the secure detection of urea toward the hot core Sgr B2(N1) at a position called N1S slightly offset from the continuum peak, which avoids obscuration by the dust. The identification of urea relies on nine clearly detected transitions. We derive a column density of 2.7 × 1016 cm−2 for urea, two orders of magnitude lower than the column density of formamide, and one order of magnitude below that of methyl isocyanate, acetamide, and N-methylformamide. The latter molecule is reliably identified toward N1S with 60 clearly detected lines, confirming an earlier claim of its tentative interstellar detection. We report the first interstellar detections of NH2CH18O and 15NH2CHO. We also report the nondetection of urea toward the secondary hot core Sgr B2(N2) with an abundance relative to the other four species at least one order of magnitude lower than toward the main hot core. Our chemical model roughly reproduces the relative abundances of formamide, methyl isocyanate, acetamide, and N-methylformamide, but it overproduces urea by at least one order of magnitude. Conclusions. Urea is clearly detected in one of the hot cores. Comparing the full chemical composition of Sgr B2(N1S) and Sgr B2(N2) may help understand why urea is at least one order of magnitude less abundant in the latter source.

In Vitro Modification of Bacterial Cyanophycin and Cyanophycin Dipeptides Using Chemical Agents Towards Novel Variants of the Biopolymer

Variations of the composition of cyanophycin (CGP) have been investigated since the early 2000s. Modifications of the polymer are of academical interest, but also expand the number of putative applications for CGP and its dipeptides in fields like food supplementations, and medical and cosmetic applications. Until recently variations of the composition occurred only in vivo. However, in the last years, two procedures using chemical or enzymatic in vitro modification were successfully applied. Since chemical treatments were more effective and reached higher conversion rates, a search for reagents and their applicability to conduct reactions with CGP was done. The reaction of CGP with methyl isocyanate resulted in the conversion of 50% of the lysine residues, while only 3% of the arginine residues were modified. However, using digested CGP dipeptides, the conversion rates of lysine increased slightly to 72%, while the conversion of arginine reached 96%. Using formaldehyde, CGP could be methylated with a conversion rate of 84% for lysine and 15% for arginine. Acetylation of lysine residues was obtained using acetic anhydride, reaching a conversion rate of 100% for a single acetylation, where 63% of the residues were acetylated twice. Arginine residues could be acetylated at a rate of 89%. Diacetyl could be added to 80% of all arginine residues, while lysine was not targeted by the compound. Other agents were also tested, but showed lesser or no conversion and/or inconclusive results. Overall, the tested reactions confirm the viability of chemical CGP modification for future approaches.

Synthesis of Complex Organic Molecules in Soft X-Ray Irradiated Ices

Abstract We study the chemical evolution of H2O:CO:NH3 ice mixtures irradiated with soft X-rays, in the range of 250–1250 eV. We identify many nitrogen-bearing molecules such as, e.g., OCN−, , HNCO, CH3CN, HCONH2, and NH2COCONH2. Several infrared features are compatible with glycine or its isomers. During the irradiation, we detected through mass spectroscopy many species desorbing the ice. Such findings support the infrared identifications and reveal less abundant species without clear infrared features. Among them, m/z = 57 has been ascribed to methyl isocyanate (CH3NCO), a molecule of prebiotic relevance, recently detected in protostellar environments. During the warm-up after the irradiation, several infrared features including the 2168 cm−1 band of OCN−, the 1690 cm−1 band of formamide, and the 1590 cm−1 band associated with three different species, HCOO−, CH3NH2, and survive up to room temperature. Interestingly, many high masses have also been detected. Possible candidates are methylformate, (m/z = 60, HCOOCH3), ethanediamide (m/z = 88, NH2COCONH2), and N-acetyl-L-aspartic acid (m/z = 175). The latter species is compatible with the presence of the m/z = 43, 70, and 80 fragments. Photodesorption of organics is relevant for the detection of such species in the gas phase of cold environments, where organic synthesis in ice mantles should dominate. We estimate the gas-phase enrichment of some selected species in the light of a protoplanetary disk model around young solar-type stars.

Exposure index of methyl isocyanate (MIC) gas disaster and a comprehensive spectrum of cytogenetic analysis after 30 years.

Severity of clinical expression and high mortality could not facilitate establishing exposure index/association following MIC disaster in Bhopal. Mortality-based exposure stratification was critiqued by the International Medical Commission on Bhopal (IMCB). IMCB stratified exposure considering distance as surrogate at 2km intervals after 10years. The first follow-up cytogenetic screening of the pre-screened survivors after 30years has demonstrated chromosome abnormalities (CA). Exposure stratification was attempted considering cytogenetic screening conducted during 1986-1988. Elevation of CA appeared proportional to exposure status and authenticated the initial mortality-based stratification. The one-on-one comparison of the previous and present cytogenetics has described the individual response to MIC exposure over 30years. Chi-square test has been carried out for checking the cytogenetic changes at the individual level statistically, which revealed that differences of chromosomal aberrations collected immediately post-disaster and 30years later are nonsignificant. The prominence of interindividual variation was noticed in general. The impact of overall exposure was higher in males. Constitutional abnormalities in 8.5% of the study population, including translocation, inversion, deletion, fragile sites, etc., necessitate screening of blood-linked members. The incidence of acrocentric association was prominent in the study population. Normal karyotype in children born to severely exposed parents with congenital anomalies indicates necessity of molecular karyotyping and/or screening of mutations. The study highlights follow-up of the health of the index cases at shorter (3-6months) intervals. This comprehensive spectrum of cytogenetic report highlights immediate post-disaster chromosomal aberrations, the changes that occurred over 30years in conjunction with other environmental factors at the individual level, constitutive genomic aberrations, polymorphic variations, and chromosomal patterns in congenitally malformed children of the survivors, which collectively indicate the possibility of acquisition/persistence of stable aberrations in MIC-exposed lymphocytes through interaction with environmental/biological confounders.

Solubility and solution-phase chemistry of isocyanic acid, methyl isocyanate, and cyanogen halides

Abstract. Condensed-phase uptake and reaction are important atmospheric removal processes for reduced nitrogen species, isocyanic acid (HNCO), methyl isocyanate (CH3NCO), and cyanogen halides (XCN, X = Cl, Br, I); yet many of the fundamental quantities that govern this chemistry have not been measured or are not well studied. These nitrogen species are of emerging interest in the atmosphere as they have either biomass burning sources, i.e., HNCO and CH3NCO, or, like the XCN species, have the potential to be a significant condensed-phase source of NCO− and therefore HNCO. Solubilities and the first-order reaction rate of these species were measured for a variety of solutions using a bubble flow reactor method with total reactive nitrogen (Nr) detection. The aqueous solubility of HNCO was measured as a function of pH and had an intrinsic Henry's law solubility of 20 (±2) M atm−1 and a Ka of 2.0 (±0.3) × 10−4 M (pKa = 3.7±0.1) at 298 K. The temperature dependence of HNCO solubility was very similar to other small nitrogen-containing compounds, such as HCN, acetonitrile (CH3CN), and nitromethane, and the dependence on salt concentration exhibited the “salting out” phenomenon. The rate constant of reaction of HNCO with 0.45 M NH4+, as NH4Cl, was measured at pH = 3 and found to be 1.2 (±0.1) × 10−3 M−1 s−1, faster than the rate that would be estimated from rate measurements at much higher pHs. The solubilities of HNCO in the non-polar solvents n-octanol (n-C8H17OH) and tridecane (C13H28) were found to be higher than aqueous solution for n-octanol (87±9 M atm−1 at 298 K) and much lower than aqueous solution for tridecane (1.7±0.17 M atm−1 at 298 K), features that have implications for multi-phase and membrane transport of HNCO. The first-order loss rate of HNCO in n-octanol was determined to be relatively slow, 5.7 (±1.4) × 10−5 s−1. The aqueous solubility of CH3NCO was found to be 1.3 (±0.13) M atm−1 independent of pH, and CH3NCO solubility in n-octanol was also determined at several temperatures and ranged from 4.0 (±0.5) M atm−1 at 298 K to 2.8 (±0.3) M atm−1 at 310 K. The aqueous hydrolysis of CH3NCO was observed to be slightly acid-catalyzed, in agreement with literature values, and reactions with n-octanol ranged from 2.5 (±0.5) to 5.3 (±0.7) × 10−3 s−1 from 298 to 310 K. The aqueous solubilities of XCN, determined at room temperature and neutral pH, were found to increase with halogen atom polarizability from 1.4 (±0.2) M atm−1 for ClCN and 8.2 (±0.8) M atm−1 for BrCN to 270 (±54) M atm−1 for ICN. Hydrolysis rates, where measurable, were in agreement with literature values. The atmospheric loss rates of HNCO, CH3NCO, and XCN due to heterogeneous processes are estimated from solubilities and reaction rates. Lifetimes of HNCO range from about 1 day against deposition to neutral pH surfaces in the boundary layer, but otherwise can be as long as several months in the middle troposphere. The loss of CH3NCO due to aqueous-phase processes is estimated to be slower than, or comparable to, the lifetime against OH reaction (3 months). The loss of XCNs due to aqueous uptake is estimated to range from being quite slow, with a lifetime of 2–6 months or more for ClCN and 1 week to 6 months for BrCN to 1 to 10 days for ICN. These characteristic times are shorter than photolysis lifetimes for ClCN and BrCN, implying that heterogeneous chemistry will be the controlling factor in their atmospheric removal. In contrast, the photolysis of ICN is estimated to be faster than heterogeneous loss for average midlatitude conditions.

Solvent Free Quick Conversion of Mono - And Dicarboxylic Acids into Their Corresponding Anilides with Phenylisothiocyanate

The attraction of isothiocyanates as synthons and as cyclizing agents continues due to their diverse reactions and also due to their easy availability. It would not be out of place to mention that, in comparison to isocyanates (-N=C=O), their Sulphur analogues, isothiocyanates (-N=C=S), are less unpleasant and to some extent less hazardous. The use of isocyanates is drastically limited by the researchers [6] after December 3, 1984 which is the date of Bhopal Disaster held in Union carbide factory, Bhopal, Madhya Pradesh (India) due to the leakage of Methyl isocyanate (MIC) where thousands of people were died due to the toxic effect of MIC (Me-N=C=O). In the present study, a mixture of Phenyl isothiocyanate (2) and monocarboxylic acid (1), in the ratio of 1:1 and Phenyl isothiocyanate (2) and dicarboxylic acid (4) in the ratio of 2:1are taken for condensation reaction by heating at 160°-170°C for 15 minutesunder solvent free condition. Pyridine was used as a catalyst/ base in both the cases. The products obtained were monoanilides (3) and dianilides (5) of mono- and dicarboxylic acids respectively which were recrystallized from aqueous ethanol. Dicarboxylic acids gave unexpected results in some of the cases. For example, Phthalic acid produces N-phenylphthalimide irrespective of the molar ratio of the acid and Phenyl isothiocyanate whereas maleic acid produces neither mono- nor dianilides with Phenyl isothiocyanate under the present condition. A proper systematic investigation was carried out towards the condensation of Phenyl isothiocyanate with mono- and dicarboxylic acids.

A Study on the Horrendous Industrial Mass Disaster at Union Carbide Plant of Bhopal in Light of Ethical Dimension

The bhopal Gas tragedy, considered as one of the most horrendous industrial mass disaster, is unparalleled in its magnitude and devastation in the history of mankind.1 The incident occurred on the night of 2–3 December 1984 when a highly toxic chemical named Methyl Isocyanate (MIC) leaked into the atmosphere from the plant of Union Carbide (India) Limited(UCIL). Methyl Isocyanate (MIC) usually written as CH3CNO is an extremely toxic, volatile and flammable gas whose density is more than the density of air and has no possible antidote.2 The US Defense Department also tested MIC as a warfare agent in 1944.3 Since the density of the gas is more than that of air, its leakage into the atmosphere led to the formation of toxic gas clouds, very close to the ground level which eventually spread into the entire city of bhopal. Thousands of people lost their life. As per Times of India Report 16177 death claims were filed and 7000 death case compensation were awarded till November 27, 1994.4 The government of Madhya Pradesh confirmed 3787 deaths.5 In an affidavit filed in the Supreme Court by the Government of India on 26th October, 2006 the government stated that the gas leak led to 5, 58, 125 injuries.6