Methyl isocyanate properties

Beneficial Micro Reactor Properties for the Synthesis of Methyl Isocyanate... 

The biocidal activity of the thiadiazine (12) is probably related to the production of methyl isocyanate inside the cell by hydrolysis (equation 7). Isocyanates are known to have fungicidal properties (B-69MH1502), thought to be due to their reaction with sulfhydryl groups to form dithiocarbamates. The formation of these last mentioned compounds, by ring cleavage, might also explain the activity of 2-mercaptobenzothiazole (16). 

Isocyanates are compounds with the general formula R-N=C=0. They have numerous uses in chemical synthesis, particularly in the manufacture of polymers with carefully tuned specialty properties. Methyl isocyanate is a raw material in the manufacture of carbaryl insecticide. Methyl isocyanate (like other isocyanates) can be synthesized by the reaction of a primary amine with phosgene in a moderately complex process, represented by reaction 15.8.1. Structures of three significant isocyanates are given in Figure 15.7. 

TABLE 21.3. Properties of methyl isocyanate (MIC) and hydrogen cyanide (HCN)... 

Maginniss, L.A., Szewczak, J.M., Troup, C.M. (1987). Biological effects of short-term, high-concentration exposure to methyl isocyanate. TV. Influence on the oxygen-binding properties of guinea pig blood. Environ. Health Perspect. 72 35-8. 

Physical Properties of 1,2,4-Thiadiazoles. The X-ray determination of the 1 1 adduct between Hector s Base (274 R = H) and methyl isocyanate shows that it forms without a heterocyclic rearrangement the compound is a 5-(iV-methylthiocarbamoylimino)4-phenyl-3-phenylamino-4//-l,2,4-thia-diazoline [274 R = MeNHC(S)]... 

TABLE 1. Physicochemical Properties of Methyl Isocyanate (MIC) and Dispersal in Bhopa)... 

Hyperbranchedpolytriallylsilanes functionalized with NCN [C H3X(CH2NMe2)2-2,6] ligands were reported by van Koten and Frey [19]. The soluble supports were used as ligands for the Pd-catalyzed aldol condensation of benzaldehyde and methyl isocyanate. Activities similar to that of parent NCN-Pd complexes were observed (Scheme 2). The hyperbranched polymeric systems showed similar properties to those of analogous dendritic compounds, indicating that structural perfection is not always required. The polymers were purified by means of dialysis, showing a potential application in continuous-flow membrane reactors. 

We may all say accidents happen. However, their occurrence may not only take human lives, destroy millions of dollars in property and lost business, they may also cost us our jobs and reputations. The Bhopal, India, accident in 1984 released methyl isocyanate and caused over 2500 fatalities. A petroleum refinery blew up in Houston, Texas, in 1989, killing 23 workers and damaging properly totaling U.S. 750 million, spewing debris from the explosion over an area of 9 km. Many thought that after the Three Mile Island nuclear accident in the United States in 1979 and the Chernobyl nuclear power plant disaster in Ukraine in 1986, we would finally get a handle on how to prevent accidents. Unfortunately, the Fukushima nuclear accident in 2011 proved otherwise (see Picture 2.1). 

The interaction of 2-alkyl-A -thiazolines (196) and aryl isocyanates in the presence of catalytic amounts of boron trifluoride etherate, or methyl isocyanate, produces cyclic 2 2 adducts (197), e.g. 6, 8a -dimethyl-3-methylcarbamoyl-5 -oxospiro(thiazolidine-2,7 -perhydrothiazolo[3,2-c]pyri-midine). This contrasts with the formation of the simple 2 1 adducts (198) in the absence of the catalyst (see these Reports, Vol. 2, p. 627). The 2 2 adducts may have one of several possible structures their formulation as (197) is based on their spectral properties and the results of their... 

Aliphatic hyperbranched polyesters, 56 Aliphatic isocyanate adducts, 202 Aliphatic isocyanates, 210, 225 Aliphatic polyamides, 138 Aliphatic polyesteramides, 56 Aliphatic polyesters, 18, 20, 29, 32, 87 degradable, 85 hyperbranched, 114-116 melting points of, 33, 36 structure and properties of, 40-44 syntheses of, 95-101 thermal degradation of, 38 unsubstituted and methyl-substituted, 36-38... 

To address this concern uretonimine-modified isocyanates with improved low-temperature properties were prepared using 4,4 -diphenylmethane diisocyanate catalyzed with 3-methyl-l-phenyl-3-phospholene-l-oxide. The formation of uretonimine was consistently higher than uretdione formation using this catalyst. The uretonimine-modified isocyanate can be stored at temperatures substantially lower than ambient temperature while still remaining liquid. In addition it is soluble in melted 4,4 -diphenylmethane diisocyanate. 

Carbonylation of organic substrates was investigated using these well defined complexes. These carbonyl compounds exhibited catalytic properties in the carbonylation of organic substrates. In particular methanol carbonylation to methyl acetate in the gas phase was successfully attempted. Mechanistic and kinetic studies of this reaction over rhodium and iridium zeolites showed the similarities between the homogeneous and the zeolite mediated reactions. Aromatic ni-tro compounds were also converted to aromatic isocyanates using similar catalytic systems. The mechanistic aspect of this reaction will be also examined. 

Mild thermal rearrangement of the carbonyl azides 408 in 1-methylpyrrole gave l-methyl-A -(2-thiophene)-, l-methyl-iV-(2-selenophene)- and l-methyl-iV-(2-furano)-l//-pyrrole-2-carboxamides 409 in good yields, presumably involving the intermediacy of the corresponding isocyanate (Equation 97) <2000ARK58>. In this case, the successful outcome of such thermal reactions is ascribable to the pronounced acidic property of the pyrrole 2-proton. 

CHEMICAL PROPERTIES stable under ordinary conditions of use and storage hazardous polymerization has not been reported dissociates in some solvents to form carben-dazim and butyl isocyanate decomposes in aqueous solution to methyl n-(benzimidazolyl) carbamate and the ethyl analog decomposes without melting above 300 C (572°F) decomposed by strong acids and strong alkalies FP (NA) LFL/UFL (NA) AT (NA) HC (NA). 

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