Decomposition odours

BrCHi CHjBr. A colourless liquid with a sweet odour, m.p. 10°C, b.p. 132°C. Manufactured by passing ethene through bromine or bromine and water at about 20 C. Chemical properties similar to those of 1,2-dichloroethane when heated with alkali hydroxides, vinyl bromide is formed. Used extensively in petrols to combine with the lead formed by the decomposition of lead tetraethyl, as a fumigant for stored products and as a nematocide. 

Aromatic aldehydes usually have relatively high boiling points, but distil with little or no decomposition. The vapours burn with a smoky flame. They are easily oxidised on standing in the air into the corresponding acids the odours are often pleasant and characteristic. Aromatic aldehydes, by virtue of their high molecular weight, yield... 

Thioethers are neutral stable compounds that can be freed from acidic and basic impurities as described for disulfides. They can be recrystallised from organic solvents and distilled without decomposition. They have sulfurous odours. 

Girard Reagent T (2-hydrazino-N,N,N-trimethyi-2-oxo-ethanaminium chioride) [123-46-6] M 167.6, m 192 . Should be crystd from absolute EtOH (slight decomposition) when it has a slight odour, and stored in tightly stoppered containers because it is hygroscopic. 

Azocarbonamide (I) Carbonamide N2, CO, CO2 190-230 220 Most widely used blowing agent in PVC and polyolefins. High decomposition temperature reduced by a variety of metal salts and oxides such as lead carbonate, lead phosphite and zinc oxide. High gas yield. Reaction products show little odour or discoloration. ... 

Calcium hypochlorite Ca(CIO), Water soluble white crystals or powder with strong chlorine odour Non-flammable but can evolve Cb and O2 May undergo decomposition Water spray may be used but evolves Cb gas freely at ordinary temperatures with moisture... 

Thiazyl trifluoride, a colourless gas with a pungent odour, is prepared by the oxidative decomposition of FC(0)NSF2 with Agp2 (Eq. 8.5).NSF3 is kinetically very stable even in the liquid form. The chemical inertness of NSF3 resembles that of SFe. For example, it does not react with sodium metal below 200°C. ... 

A s/cr.s possess a fruity smell and usually distil without decomposition. Boil with refltiK for 5 minutes on the water-btith a few c.c. of the licpiid with 3 to 4 volumes of a ten pei cent, solution of ctLListic potash in methyl alcohol and pour into water. Notice if the liquid dissolves and has lost the odour of the ester. An ester will be completely hydrolysed, and if the alcohol is soluble in water a clear solution will be obtained. If the alcohol is vol.atile and the solution neiitialised w ith sulphuric acid. and evaporated on the water-bath, the alkali salt of the organic acid mixed with pottissium sulphate will be left and the acid may be investigated as desciibed under 1. If it is required to. ascertain the nature of the alcohol in the ester, hydrolysis must fig effected with a strong aqueous solution of caustic potash... 

The resulting oil is brownish iu coloor with a most unpleasant odour, due to the presence ot decomposition products, which inclnde phenols, furfural, and benzenoid hydrocarbons. 

May undergo decomposition Yellowish-red oily fuming liquid with a strong odour Combustible flash point 118°C Ignition temp. 233°C Liquid and vapours are irritating... 

Water Reclamation Works by their very nature can, at times be the source of unpleasant odorous emission. The odour-intensive compounds (osmogenes) which make up these emissions are believed to arise mainly as the decomposition products of carbohydrates and proteins. The breakdown of this waste material proceeds by aerobic and anaerobic processes at various stages of the treatment plant. Atmospheric pollution of this nature frequently results in complaints from members of the public either resident, or perhaps employed in the vicinity of such works. In order to confirm or deny that a reclamation works is responsible for a particular nuisance and, if possible to identify the causal agents it was decided that the Authority should have the capability of analysing for odorous and other polluting constituents of the atmosphere. This paper describes the progress made towards this objective and summarises the experience gained with a procedure in use. There are two principle approaches available for the analytical classification of odorous emissions -... 

The results obtained with this procedure are similar to those previously reported in the literature by Hangartner, Hagenguth et al and Zeman et al (4, 2, 5, 6). The major exception, being the complete lack of alkylated pyrazines and alkylated thiophenes. These odour-intensive compounds arise from the thermal decomposition of proteins and sulphur containing amino acids. They also develop in the thermally induced reaction of proteins with carbohydrates (Maillard reaction). The authors indicated above have demonstrated that these compounds are invariably produced during the thermal treatment of sludge, a process which is not used in this Authority. 

The malodorous emission in this case appears to be dominated by volatile fatty acids and cresol. It is interesting to note in passing that cresol is one of the few odour-intensive species found in almost all odorous emission so far encountered. This osmogene is usually present in sufficient quantities to be clearly detectable of the odour port. Cresol and phenol (only found occasionally) is reported to be formed by the decomposition ol lignin. 

Amines with low molecular masses have a distinctive fishy smell. Also, many offensive odours of decay and decomposition are caused by amines. For example, cadavarine, H2NCH2CH2CH2CH2CH2NH2, contributes to the odour of decaying flesh. This compound gets its common name from the word cadaver, meaning dead body. ... 

Mercury fulminate is relatively resistant to the action of dilute acids, in particular to that of nitric acid, but concentrated acids cause decomposition. Thus, under the influence of nitric acid decomposition occurs with evolution of NO, CO, acetic acid and mercuric nitrate. Under the influence of concentrated hydrochloric acid free fulminic acid is evolved (with an odour resembling that of hydrogen cyanide) as well as the decomposition products hydroxylamine hydrochloride, formic acid, mercuric chloride (Carstanjen and Ehrenberg [32] Scholl [33]). Mercury fulminate explodes on direct contact with concentrated sulphuric acid. 

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