Chloropicrin preparation

Hypochlorites decomp PA, which undergoes chlorination to form chloropicrin. The reaction is carried out with Ca hypochlorite. The Ca 0 hydroxide formed in the reaction neutralizes the hydrochloric acid formed. This is a commercial method of preparing. chloropicrin ... 

Methylamine occurs in herring brine 2 in crude methyl alcohol from wood distillation,3 and in the products obtained by the dry distillation of beet molasses residues.4 It has been prepared synthetically by the action of alkali on methyl cyanate or iso-cyanurate 5 by the action of ammonia on methyl iodide,6 methyl chloride,7 methyl nitrate,8 or dimethyl sulfate 9 by the action of methyl alcohol on ammonium chloride,10 on the addition compound between zinc chloride and ammonia,11 or on phos-pham 12 by the action of bromine and alkali on acetamide 13 by the action of sodamide on methyl iodide 14 by the reduction of chloropicrin,15 of hydrocyanic or of ferrocyanic acid,16 of hexamethylenetetramine,17 of nitromethane,18 or of methyl nitrite 19 by the action of formaldehyde on ammonium chloride.20... 

A solution of sodium ethoxide is prepared under nitrogen from 70 g. (3.04 gram atoms) of sodium and 2-1. of absolute ethanol (Note 1) in a 3-1. three-necked flask which is equipped with mechanical stirrer, efficient reflux condenser, dropping funnel, and a thermometer which dips below the level of the liquid in the flask. Chloropicrin (100 g., 0.61 mole) (Note 2) is placed in the dropping funnel, and the stirred solution is heated to 58-60° with a water bath. The chloropicrin is added at a rate of 30-35 drops per minute until the reaction becomes self-sustaining (about 20 minutes), at which point the water bath is removed and the balance of the chloropicrin is added at a rate sufficient to maintain the temperature at 58-60° (Note 3). When the addition, which requires nearly 2 hours, is complete, the stirrer is stopped and the mixture is allowed to stand overnight. 

The above procedure is essentially that of Tieckelmann and Post.3 Ethyl orthocarbonate has been prepared by the reaction of chloropicrin and sodium ethoxide by Bassett4 and Rose.5 Thiocarbonyl perchloride has been reported 3 6 to react with sodium ethoxide to give good yields of ethyl orthocarbonate. 

Guanidine or its salts may be prepared, among other ways, by the interaction. (1) of orthocarbonic ester or (2) of chloropicrin... 

Practically all methods which have been proposed for the preparation of guanidine salts involve either ammonation or ammonolysis of some derivative of carbonic acid. Phosgene,1 chloropicrin,2 and esters of orthocarbonic acid2 react with aqueous ammonia to give small yields of guanidine. The hydrochloride is obtained when carbon tetrachloride3 is acted upon by liquid ammonia under pressure. Urea4 is partially ammonolyzed in the presence of ammonium chloride. 

Thus the authors prepared a- nitronaphthalene from naphthalene with the yield of 80% by warming I with naphthalene. In a similar way toluene was nitrated at 80°C to 2,4-dinitrotoluene (yield 65%). By warming chloroform with I at 40-50°C chloropicrine resulted with the yield of ca. 30%. 

Chloropicrin, or trichloronitromethane, was prepared in 1848 by Stenhouse. In the war of 1914-18 it was largely employed as a war gas, more particularly as it combined a simple and economic manufacture with many of the characteristic desiderata of a war gas. 

Various methods have been proposed for the preparation of chloropicrin. For example ... 

Chloropicrin may be prepared in the laboratory by the method proposed by Hoffmann. ... 

A paste of chloride of lime was first prepared and pumped into a vertical vessel of enamelled iron where it was mixed with calcium picrate prepared previously by mixing picric acid with water and an excess of lime. The mixture was allowed to react at ordinary temperatures for about 2 hours and then a current of steam was introduced at the bottom of the vessel. In these conditions the rise in temperature accelerated the reaction and at 85° C. the chloropicrin began to distil. Distillation was continued until no more chloropicrin came over. 

Recently a new method of preparation of chloropicrin has been worked out in Rumania. This uses petroleum as raw material. The principal stages of the preparation of chloropicrin by this process are as follows ... 

These low mutual solubilities facilitate their separation in the preparation and render drying of the chloropicrin unnecessary, unless it is to be employed for some special purpose, as, for example, in " NC mixture (80% chloropicrin and 20% stannic chloride),... 

In practice this determination is carried out by adding to a weighed quantity of the chloropicrin in a small flask fitted with a condenser, an excess of an aqueous-alcoholic solution of sodium sulphite, prepared by dissolving 10 gm. sodium sulphite in 250 ml. water and diluting with an equal volume of ethyl alcohol. The liquid in the flask is then carefully heated so as to distil off all but about 10 ml. This is then diluted with water to 100 ml. and 10 ml. of nitric acid and an excess of a standardised solution of silver nitrate are added. The solution is then warmed to drive off the nitrous gases and to coagulate the silver chloride, and then cooled and the excess silver nitrate titrated with a solution of ammonium thiocyanate (ferric alum indicator). 

This method of analysis was also used by Dubinin for the determination of chloropicrin in the gas mixtures prepared for the testing of activated carbons. 

Bromobenzyl cyanide was prepared by Reimer in 1881, but it was not isolated in the pure state until 1914. It was employed as a war gas by the French in the last years of the war, usually in solution in chloropicrin. 

Sulphuryl chloride was chiefly prepared during the war for the manufacture of methyl and ethyl chlorosulphonates, but was occasionally employed also in admixture with cyanogen chloride, phosgene or chloropicrin (Prentiss). 

I wish to take this opportunity to report that chloropicrin, whose formation by the distillation of nitric acid, alcohol and salt I reported earlier Am, 101, 212), can be prepared also (1) when molten or solid chloral is distilled with concentrated nitric acid or with a mixture of nitric and sulfuric acids, and (2) when a mixture of wood alcohol and sulfuric acid, poured over a mixture of saltpeter and salt, is distilled. Both methods characterize chloropicrin as a methyl derivative according to the latter, it appears to be methyl chloride whose hydrogen is substituted by chlorine and NO2 according to the first, as nitrated chloroform or as the nitrit of triply chlorinated methyl. 

Dichloroformoxime, Cl20=NOH. Mol. wt. 113.94. The reagent is a skin irritant and the vapor is toxic. It is prepared by reduction of chloropicrin with tin and... 

Chemistry Chloropicrin s first reported preparation, by the Scottish scientist John Stenhouse, was in 1848 and involved the reaction of a chlorinating agent (bleaching powder) with picric acid (iym-trinitrophenol). It is this synthesis that led to the name chloropicrin, even though the ring present in picric acid is absent in the product chloropicrin. 

The reaction of chlorine gas and aqueous sodium hydroxide with 4-hydroxy-3,5-dinitrobenzoic acid can be used to prepare chloropicrin (Simandi and Soos, 1986). 

Chloropicrin can be used to prepare orthocarbonates, C(OR)4, the process involving four replacements by alkoxide ions (Hennig, 1937) ... 

Simandi, L. and Soos, J. 1986. Preparation of Chloropicrin by Reaction of 4-Hydroxy-3,5-Dinitrobenzoates with Hypochlorites, HU Patent 1986-3814. 

Preparation. The reagent is prepared by the reaction of chloropicrin (irritant and lachrymator) with sodium methoxide.1 Compare the preparation of tetraethyl orthocarbonate.2... 

Bisarylsulfonyl and -alkylsulfonyl furoxans can be prepared by nitrosation of sulfonyldiazomethanes,239,243 from sulfonylacetic acids with nitric acid, and from chloropicrin and an arenesulfinate.216 In alcohols containing alkali, one (which one is not known) of the sulfonyl groups is replaced by alkoxide.216... 

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