Potassium isocyanate reaction with

Impurities in CL have also been destroyed by oxidation with ozone22 followed by distillation. Ozonation treatment of waste CL leaves no ionic impurities. However, the most commonly used oxidizing agents are potassium permanganate, perboric acid, perborate, and potassium bromate. Treatment of CL with these oxidizing agents is carried out in a neutral medium at 40-60°C. Strongly alkaline or acidic conditions accelerate the oxidation of CL to form isocyanates. Hie undesirable oxidation reaction is fast above pH 7 because of the reaction with isocyanate to form carbamic acid salts, which shifts the equilibrium to form additional isocyanate. 

Monocarbamoylation of diols is generally accomplished only with great difficulty. Reaction of the diol with an alkyl isocyanate is a possibility, but trimerization of the isocyanate frequently occurs [73]. The monocarbamic esters, which have PAF receptor antagonist activity, can be obtained however in acceptable yields via the phase-transfer catalysed in situ formation of the alkyl isocyanate from potassium isocyanate and an alkyl halide, and its subsequent reaction with the diol (see Scheme 3.8 for typical examples) [74], The diols tend to react more rapidly than do simple alcohols and m-diols are more effectively esterified that are /ra/rs-diols. Additionally, the longer the chain length between the hydroxyl centres, the less effective is the reaction. This has led to the reasonable hypothesis that a cyclic H-bonded intermediate between the two hydroxyl groups and the alkyl isocyanate are critical for the preferential and rapid formation of the carbamate. 

Alkyl lV,lV-dinitramines (154) have been prepared from the reaction of the tetraalkylam-monium salts (155) of primary nitramines with nitryl fluoride in acetonitrile at subambient temperature. The same reaction with the primary nitramine or its alkali metal salts yields the corresponding nitrate ester. Treatment of the ammonium, potassium, or lithium salts of primary nitramines (156) with a solution of nitronium tetrafluoroborate in acetonitrile at subambient temperature yield alkyl iV,iV-dinitramines. ° The same reactions in ether or ester solvents enables the free nitramine to be used. The nitrolysis of A-alkylnitramides (157) and N,N-diacylamines with nitronium tetrafluoroborate in acetonitrile, and the nitration of aliphatic isocyanates with nitronium tetrafluoroborate and nitric acid in acetonitrile, also yield alkyl A,A-dinitramines (154). 

Carbimazole Carbimazole, the ethyl ester of 3-methyl-2-thioimidazolin-l-carboxylic acid (25.2.7), is synthesized by a simultaneons reaction of ethylenacetal of bromoacetaldehyde with methylamine and potassium isocyanate, forming 3-methyl-2-imidazolthione (25.2.6), which is further acylated at the nitrogen atom by ethyl chloroformiate, giving the desired product (25.2.7) [17-19]. 

The resulting product is then hydrolyzed by the enzyme Citrusi acetylesterase to the potassium salt of 3-hydroxymethyl-7-methoxy-7-[2-(2-thienyl)acetamido]-3-cefem-4-carboxylic acid (32.1.2.38). Using the method described above, i.e. the initial reaction with chlorosulfonyl isocyanate followed by hydrolysis with water, the resulting compound,... 

Chemical methods used for the determination of hydroxyl groups or alcoholic constituents in polymers are based on acetylation [16-18], phthalation [18], and reaction with phenyl isocyanate [18,19] or, when two adjacent hydroxy groups are present in the polymers, by reaction with potassium periodate [9,17]. Alcoholic hydroxyl groups may be found in the following polymers (1) poly(ethylene terephthalate) (PET) [20], (2) poly(methyl acrylate), [21], (3) poly(methyl methacrylate) [21], and (4) polyhydric alcohols in hydrolysates of poly(ester) resins [22]. 

Oxazin-4-ones and -thiazin-4-ones are well represented in the chemical literature. Thiazin-4-ones can be synthesized from 1,3-oxazinium salts by the action of hydrogen sulfide and potassium carbonate (81H(15)85l) and oxazin-4-ones are obtained by cycloadditions between isocyanates and ketenes (Scheme 73), or alkynes (Scheme 74), or between nitriles and acylketenes (Scheme 75). Similarly diketene is often used and affords oxazin-4-ones by its reactions with imidates and cyanamides (Scheme 76) (80H(14)1333>. 

Chalcones may be ring-closed to oxazinones by reaction with alkyl or aryl isocyanates in boiling benzene containing a catalytic amount of potassium hydroxide. 

Thus, several mechanistic pathways based on polarization effects have been proposed to explain the catalysis of the alcohol-isocyanate reaction. These propositions appear to be often unsatisfactory and cannot explain even the majority of the experimental results reported in the literature. For an example, why is the polyurethane formation catalyzed by potassium acetate (JJ and not at all by MgC03 nor CsCl (14) The role played by the nature of the metal remains also unexplained. Robins reports the incremental temperature rise noted 1 minute after the mixing of reagents and catalyst (7, 16). This parameter is related to the catalytic activity and is an effective way to show the role played by the organometallic compound in its interaction with the alcohol. A similar conclusion can be drawn from Table I (15) where the Sn+ derivative is much more active than the Sn+2 oxidation state or Pb+. ... 

AMMONIUM SULPHATE (7783-20-2) H8N2O4S Noncombustible solid. Aqueous solution is a strong acid. Violent reaction with fused potassium chlorate potassium nitrite. Reacts with caustics, forming ammonia. Hot material reacts with nitrates, nitrites, chlorates. Incompatible with strong oxidizers sulfuric acid aliphatic amines alkanolamines, amides, organic anhydrides isocyanates, vinyl acetate aUcylene oxides epichlorohydrin. Mixture with sodium hypochlorite forms nitrogen trichloride, an unstable explosive material. Attacks metals in the presence of moisture. 

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