Dehydration, explosive

Sinnam, H. L. Eskew, R. K. Cording, J. Dehydrated Explosion Puffed Carrots with High Density, U.S. Department of Agriculture, ARS 73-50, 1965. 

Organic Reactions. Nitric acid is used extensively ia iadustry to nitrate aHphatic and aromatic compounds (21). In many iastances nitration requires the use of sulfuric acid as a dehydrating agent or catalyst the extent of nitration achieved depends on the concentration of nitric and sulfuric acids used. This is of iadustrial importance ia the manufacture of nitrobenzene and dinitrotoluene, which are iatermediates ia the manufacture of polyurethanes. Trinitrotoluene (TNT) is an explosive. Various isomers of mononitrotoluene are used to make optical brighteners, herbicides (qv), and iasecticides. Such nitrations are generally attributed to the presence of the nitronium ion, NO2, the concentration of which iacreases with acid strength (see Nitration). 

The decomposes spontaneously on standing for a few days. The acid dehydration reaction requires a day for completion at —10°C and explosions... 

The silver perchlorate [7783-93-9] salt, AgClO, is dehquescent and forms a light-sensitive monohydrate that can be dehydrated at 43°C and is soluble in a variety of organic solvents. Explosions of silver perchlorate have been reported (40—42). Gold forms organic perchlorate [42774-61-8] complexes as well as complexes with silver, eg, (CgH )2AgAu(CgF )2C104. 

R = alkyl, R = H) can be condensed, using acid, dehydrating agents (eg, phosphoms pentoxide), or vacuum to form polymeric peroxides (3). Most such polymeric peroxides decompose explosively. 

Polymeric OC-Oxygen-Substituted Peroxides. Polymeric peroxides (3) are formed from the following reactions ketone and aldehydes with hydrogen peroxide, ozonization of unsaturated compounds, and dehydration of a-hydroxyalkyl hydroperoxides consequendy, a variety of polymeric peroxides of this type exist. Polymeric peroxides are generally viscous Hquids or amorphous soHds, are difficult to characterize, and are prone to explosive decomp o sition. 

This heating prior to distillation obviates the necessity of intermediate isolation of the carbinol. The dehydration is evidenced by small explosions when the water drops on the hot reaction mixture. 

Magnesium perchlorate used as a dehydrating agent was exposed to ethanol fumes for several months, while attempting to crumble the salt formed. The detonation which followed was explained by the formation of ethyl perchlorate which is explosive on impact or frlcition. 

Large quantities are used as a raw material in the chemical process industry, especially for urea across C02 reaction with NH3 and later dehydration of the formed carbamate. Urea is the product most used as agricultural fertiliser. It is used in feed for ruminants, as carbon cellulose explosives stabiliser in the manufacture of resins and also for thermosetting plastic products, among others. 

Because trifluoromethanesulfonic acid is a stronger acid than perchloric acid, under no circumstances should perchlorate salts be used with the neat acid, because the hot anhydrous perchloric acid so formed represents an extreme explosion hazard, especially in contact with transition metal complexes (or with organic materials). See Perchloric acid Dehydrating agents See other ORGANIC ACIDS... 

Explosions which occurred at the auxiliary electrode during electro-oxidation reactions in nitromethane-lithium perchlorate electrolytes, may have been caused by lithium fulminate. This could have been produced by formation of the lithium salt of nitromethane and subsequent dehydration to the fulminate [1], analogous to the known formation of mercury (II) fulminate [2], This explanation is not considered tenable, however [3]. 

Reaction of the silane with nitromethane is explosive, probably by intermediacy of fulminic acid (a dehydration product of nitromethane). 

Made by dehydration of nitroacetaldehyde oxime, this is an explosion hazard. It is improbable that the nitrile is not, itself, detonable. 

Dining an attempt to prepare an anhydrous 25% solution of peroxyacetic acid in acetic acid by dehydrating a water-containing solution with acetic anhydride, a violent explosion occurred. Mistakes in the operational procedure allowed heated evaporation to begin before the anhydride had been hydrolysed. Acetyl peroxide could have been formed from the anhydride and peroxyacid, and the latter may have detonated and/or catalysed violent hydrolysis of the anhydride [1], A technique for preparing the anhydrous acid in dichloromethane without acetyl peroxide formation has been described [2],... 

Dining preparation of diallyl ether by dehydration of the alcohol with sulfuric acid, a violent explosion may occur (possibly involving peroxidation and certainly... 

It is explosive, and distillation, even under reduced pressure as described, may be dangerous [1], A Hungarian patent describes a safe procedure for in-situ generation of the ester, azeotropic dehydration and subsequent metal-catalysed reaction with 1,3-dienes to give alkyl cyclopropanecarboxylates [2],... 

Dehydration of the aqueous 48% acid by addition to the anhydride is rather exothermic, and caution is advised [1]. Operation at 0°C led to an explosion [2],... 

Dining dehydration of manganese(II) perchlorate [1] or nickel(II) perchlorate [2] with dimethoxypropane, heating above 65°C caused violent explosions, probably involving oxidation by the anion [1] (possibly of the methanol liberated by hydrolysis). Triethyl orthoformate is recommended as a safer dehydrating agent [2] (but methanol would still be liberated). 

A violent explosion occurred during centrifugal dehydration of an aqueous paste of the sodium salt [1], which was known to be explosive [2], The instability may be associated with the presence of some of the aci-o- or p-quinonoid salt. 

After two minor dust explosions in an industrial adipic acid dryer, evidence was obtained that adipic acid forms an iron complex capable of both decarboxyla-tion/dehydration of adipic acid to cyclopentanone and of catalysing air oxidation, giving exotherms from as low as 135°C. 

Benzyl acetate was prepared by addition of benzyl chloride (containing 0.6% pyridine as stabiliser) to preformed sodium acetate at 70°, followed by heating at 115°, then finally up to 135°C to complete the reaction. On one occasion, gas began to be evolved at the end of the dehydration phase, and the reaction accelerated to a violent explosion, rupturing the 25 mm thick cast iron vessel. This was attributed to presence of insufficient pyridine to maintain basicity, dissolution of iron by the... 

Attempts to dehydrate this to the anhydride were unsuccessful attempting to distil off monomeric products under vacuum at 80°C after a dehydration attempt with ethoxyacetylene led to a violent explosion. This is said to be atypical of cubanes, but ... 

Precautions are necessary to prevent explosions when using the mixed acids to oxidise organic materials for subsequent analysis. The sulfuric acid probably tends to dehydrate the 70% perchloric acid to produce the hazardous anhydrous acid. See Nitric acid, etc., above... 

Interaction of the anhydrous acid and sulfur trioxide is violent and highly exothermic, even in presence of chloroform as diluent, and explosions are frequent. See Dehydrating agents, above... 

In view of the ready commercial availability and apparent stability of the hexahy-drate, it is probable that the earlier report of explosion on impact, and deflagration on rapid heating [1] referred to the material produced by partial dehydration at 100°C, rather than the hexahydrate [2], The caked crystalline hydrated salt, prepared from aqueous perchloric acid and excess cobalt carbonate with subsequent heated evaporation, exploded violently when placed in a mortar and tapped gently to break up the crystalline mass, when a nearby dish of the salt also exploded [3]. Subsequent investigation revealed the probable cause as heating the solid stable hexahydrate to a temperature ( 150°C) at which partial loss of water produced a lower and endothermic hydrate (possibly a trihydrate) capable of explosive decomposition. This hazard may also exist for other hydrated metal perchlorates, and general caution is urged [4,5],... 

Addition of the dehydrated salt to acetic anhydride caused an exothermic reaction which accelerated to explosion. Presence of acetic acid (including that produced by hydrolysis of the anhydride by the hydrate water) has a delaying effect on the onset of violent reaction, which occurs where the proportion of anhydride to acid (after hydrolysis) exceeds 0.37 1, with an initial temperature above 35°C. Mixtures of dichromate (30 g) with anhydride-acid mixtures (70 g, to give ratios of 2 1, 1 1, 0.37 1) originally at 40°C accelerated out of control after 18, 43 and 120 min, to 160, 155 and 115°C, respectively. 

A mercury manometer used with ammonia became blocked by deposition of a grey-brown solid, which exploded dining attempts to remove it mechanically or on heating. The solid appeared to be a dehydration product of Millon s base and was freely soluble in sodium thiosulfate solution. This method of cleaning is probably safer than others, but the use of mercury manometers with ammonia should be avoided as intrinsically unsafe [1,2]. Although pure dry ammonia and mercury do not react even under pressure at 340 kbar and 200° C, the presence of traces of water leads to the formation of an explosive compound, which may explode during depressurisation of the system [3], Explosions in mercury-ammonia systems had been reported previously [4,5],... 

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