Toluene decomposition temperature

The determination of the excess isocyanate is more problematic. In one method, toluene diisocyanate (TDI) is vaporized below the decomposition temperature of the prepolymer and analyzed by gas chromatography. A more precise method is useful if a liquid chromatograph is available. The NCO groups are reacted with methanol and the prepolymer is separated into its constituent parts in a size exclusion column. The methanol-capped isocyanates constitute the lowest molecular weight fraction. The isomers of TDI are differentiated by this technique. 

Studies of benzene and toluene oxidation in the turbulent flow reactor at Princeton University have provided valuable information on the mechanisms of oxidation at temperatures in excess of 1000 K [213]. The first extensive study of benzene and toluene at temperatures of about 750 K was made by Burgoyne [35]. Apart from CO and CO2, the major products of benzene oxidation that were detected were phenols and acids. An autocatalytic reaction was observed by Burgoyne [35] presumably driven by H2O2 formation and decomposition. Amongst the main products of toluene slow oxidation were benzyl alcohol, benzaldehyde and benzoic acid. Phenolic compounds were also reported. This reaction also showed an autocatalytic development. An equilibrium constant for the equilibrium between benzyl and benzylperoxy radicals has been measured by Fenter et al. [214], but this cannot be followed by an isomerization in the way that is possible in alkanes. 

The iron vapor-toluene reaction has evoked interest because of the lability of the proposed bis(arene)iron complex to ligand subsitu-tion and to loss of both toluene molecules to free the metal atom. In the latter case the toluene molecules may be usefully regarded as metal atom carriers which can be used to direct the latent reactivity of the atom in subsequent solution phase chemistry. In this way the metal atom experiment can benefit from the convenience and additional versatility afforded by bench-top chemical manipulations. These results are relevant to a reported preparation of a dehydroxy-lated silica-supported Fischer-Tropsch catalyst from a static reactor codeposition of Fe and toluene.(46) In the liquid phase, iron atoms "bottled" in this way have also been utilized in an exceedingly mild method for making minute catalytically active superparamagnetic clusters on the surface and within the cavities of a dehydrated sodium zeolite Y.(38) Using the rotary reactor, preformed solutions of solvated iron atoms (as the toluene complex) are cannulated below their decomposition temperature out of the flask to a cold slurry of the support in toluene. Diffusion of intact... 

When a diazonium fluoroborate gives only a poor yield of the corresponding fluorinated aromatic compound on thermal decomposition in the dry state, it may be added in portions to an anhydrous hydrocarbon that is heated a few degrees above the decomposition temperature of the fluoroborate m- and o-fluoropropiophenone, for instance, have been obtained in this way in boiling toluene or heptane 1245 the procedure has also been applied, in particular, to decomposition of heterocyclic diazonium fluoroborates, e.g., for the preparation of 3-fluoropyridine,1246 3-fluoroquinoline,1247 and 4-fluoroisoquino-line.1248... 

Seven alkenediazonium hexachloroantimonates and three alkenediazonium tetra-chloro(4-toluene-sulfinato)stannates were synthesized by Bott (1975). All except the 2-chlorobut-l-enediazonium hexachloroantimonate can be isolated, and all decompose in the solid state, depending on substituents, in the range 50-132°C. It seems that the stability, as reflected in the decomposition temperature, is related to the stability of the vinyl cations formed. A systematic investigation of these problems, which could define the potential of alkenediazonium ions for synthetic applications, would be desirable. At present, there are very few reactions known of alkenediazonium ions that have such a potential (see Sect. 9.5). 

III. In this process a tungsten wire, which serves only as a substratum for the deposit, is heated to glowing in an atmosphere consisting of a volatile halide of the metal, a carbon compound and Hg. Moers recommends the use of hydrocarbons such as toluene, instead of CO the deposition of free carbon with the carbide is avoided if the partial pressure of the hydrocarbon in the system is low. The hydrogen atmosphere facilitates considerably the reaction at the glow wire by reducing the decomposition temperatures of the halides to a much greater extent than does reduced pressure or even vacuum. 

Demidyuk, V. and Whitehead, J.C. (2007). Influence of temperature on gas-phase toluene decomposition in plasma-catalytic system. Plasma Chem. Plasma P, 27, pp. 85-94. 

Dimeric hydrides of the (Cp2LuH)2 type are formed also as a result of the P eliminating process in the decomposition of tert- and secondary-butyl complexes Cp2LnR(THF) in toluene at temperature -30 75°C [9, 22, 23]. However, this route is... 

Toluenesulfonamide Resin n Resins made by the interaction of toluene sulfonamide and formaldehyde. p-Toluenesulfonylhydrazide n A blowing agent similar to benzene-sulfonylhydrazide, but having higher melting and decomposition temperatures. 

The molecular structure of MATS is shown in Fig.l (a). The merits of MATS include its good solubility in common organic solvents, such as toluene, hexane, and acetonitrile, and its relatively high decomposition temperature (approximately 220 C). Because MATS has a melting temperature of aprproximately 56 °C, frozen junction devices can be prepared for... 

Tactic polynorbornenes produced by metallocene catalysts are crystalline and show a melting temperature of about 600 ° C in vacuo, but they decompose before melting. This makes them unsuitable for a technical use. If different substituted polynorbornenes are copolymerized, materials are obtained that are soluble in toluene and have a melting temperature below 400 °C, the decomposition temperature. Homo- and copolymers with different alkyl or functional groups are commercialized by Promerus. ... 

The evolution of the gaseous product in this polymerization makes the initial Diels-Alder reaction irreversible. This factor probably contributes to the ease with which high molecular weight polymers are obtained. Recently, two groups of workers have described the polymerization of diacelylenes with bis(cyclo-pentadienones) (79,21,27). An example is shown in Eq. (111-15). The reactants were heated together in a sealed tube at 300°C for 50 hours with toluene as a solvent. Relatively high molecular weight products were obtained (27). The polymers were also notable in that they possessed decomposition temperatures of 470°-550°C in air (27). Other examples are listed in Table 111.1. 

These can be converted to their uranyl nitrate addition compounds. The crude or partially purified ester is saturated with uranyl nitrate solution and the adduct filtered off. It is recrystallised from -hexane, toluene or ethanol. For the more soluble members crystallisation from hexane using low temperatures (-40°) has been successful. The adduct is decomposed by shaking with sodium carbonate solution and water, the solvent is steam distilled (if hexane or toluene is used) and the ester is collected by filtration. Alternatively, after decomposition, the organic layer is separated, dried with CaCl or BaO, filtered, and fractionally distilled under high vacuum. 

Benzyioxycarbonyi chioride (Cbz-Ci, benzyi cbioroformate) [501-53-1] M 170.6, b 103 /20mm, d 1.195, n 1.5190. Commercial material is better than 95% pure and may contain some toluene, benzyl alcohol, benzyl chloride and HCl. After long storage (e.g. two years at 4 , Greenstein and Winitz [The Chemistry of the Amino Acids Voi 2 p. 890, J Wiley and Sons NY, 1961] recommended that the liquid should be flushed with a stream of dry air, filtered and stored over sodium sulfate to remove CO2 and HCl which are formed by decomposition. It may further be distilled from an oil bath at a temperature below 85 because Thiel and Dent [Annalen 301 257 1898] stated that benzyioxycarbonyi chloride decarboxylates to benzyl chloride slowly at 100 and vigorously at 155 . Redistillation at higher vac below 85 yields material which shows no other peaks than those of benzyioxycarbonyi chloride by NMR spectroscopy. LACHRYMATORY and TOXIC. 

Trichloro- and dichloromethane, ether, dioxane, benzene, toluene, chlorobenzene, acetonitrile, or even pyridine itself has been employed to carry out the one-pot syntheses. Tliese solvents allow straightforward preparation of the salts. The temperature range between 0° and 20°C is usually employed and the salts formed are sufficiently soluble. In the case of slow reactions, selection of a solvent with a higher boiling point is prohtable since thermal instability of the A -(l-haloalkyl)heteroarylium halides has not been reported. Addition of water or an aqueous solution of sodium acetate does not cause a rapid decomposition of the salts so that this constitutes a useful step in the optimization of some procedures. 

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