Benzene phosgene

FIG. 23-3 Temperature and composition profiles, a) Oxidation of SOp with intercooling and two cold shots, (h) Phosgene from GO and Gfi, activated carbon in 2-in tubes, water cooled, (c) Gumene from benzene and propylene, phosphoric acid on < uartz, with four quench zones, 260°G. (d) Mild thermal cracking of a heavy oil in a tubular furnace, hack pressure of 250 psig and sever heat fluxes, Btu/(fr-h), T in °F. (e) Vertical ammonia svi,ithesizer at 300 atm, with five cold shots and an internal exchanger. (/) Vertical methanol svi,ithesizer at 300 atm, Gr O -ZnO catalyst, with six cold shots totaling 10 to 20 percent of the fresh feed. To convert psi to kPa, multiply by 6.895 atm to kPa, multiply by 101.3. 

Nitrophenyl isocyanate has been prepared by heating -nitrophenyl carbamyl chloride. The latter has been obtained by the action of phosgene on -nitroaniline in benzene-toluene solutions, and by the action of phosphorus pentachloride on methyl jii-nitrophenylcarbamate. The preparation given above is based upon recent publications of the authors. ... 

If a substituted aromatic hydrocarbon is used, the ketone gioLip then enteis the paia-position, or, if this is occupied, the oitho-position. Substituted aromatic acid chlorides may. also be used, and if the acid is dibasic and has two caiboxyl chloiide gioups, two molecules of the aromatic hydiocaibon may be. attached. If phosgene is used with two molecules of benzene, benzophenone is obtained. 

A solution in dry benzene of 82 grams of bis(/3-chloroethyl)amine freshly liberated from its hydrochloride is added gradually to a solution of 36 grams of carbonyl chloride (phosgene) in benzene at a temperature below 10°C. The mixture is mechanically stirred for 3 hours, the precipitate of bis()3-chloroethyl)amine hydrochloride is removed by filtration and the benzene is distilled off on a water bath. The residue is distilled in vacuo and the N-ch oro-formyl-bis((3-chloroethy )amine is obtained as a pale yellow oil with a 8P of 114° to 116°C at 1 mm Hg. 

A solution of 32 g (030 mol) phosgene in 200 ml benzene is added dropwise at 30°C to a stirred soiution of 53.5 g (032 mol) 3-o-toloxy-13-Pfopanediol in 400 ml benzene. The mixture is stirred for an hour after the addition is completed, and a solution of 39 g of dl-methylaniline in 100 ml benzene is then added, and stirring continued for a half-hour. Ice water (about one-third volume) is then added, and the benzene layer formed is separated and stirred with 500 ml concentrated ammonia at 5°Cfor six hours. The precipitated solid (weighing about 55 g) is recovered and recrystallized from water. The product thus obtained in a yield of about 53 g is 3-(o-toloxy)-2-hydroxypropyl carbamate it is a crystalline solid melting at about 93°C, and having a lower water-solubility and higher oil-solubility than 3-o-toloxy-13-propanediol. 

A 12.5% solution of phosgene in benzene is available from Matheson, Coleman and Bell. 

Benzophenone has been prepared by the distillation of calcium benzoate,1 by the action of benzoyl chloride on benzene in the presence of aluminium chloride,2 by the action of phosgene on benzene in the presence of aluminium chloride,3 by the action of carbon tetrachloride on benzene in the presence of aluminium chloride followed by hydrolysis.4... 

The reaction with disubstituted formamides and phosphorus oxychloride, called the Vilsmeier or the Vilsmeier-Haack reaction,is the most common method for the formylation of aromatic rings. However, it is applicable only to active substrates, such as amines and phenols. An intramolecular version is also known.Aromatic hydrocarbons and heterocycles can also be formylated, but only if they are much more active than benzene (e.g., azulenes, ferrocenes). Though A-phenyl-A-methyl-formamide is a common reagent, other arylalkyl amides and dialkyl amides are also used. Phosgene (COCI2) has been used in place of POCI3. The reaction has also been carried out with other amides to give ketones (actually an example of 11-14),... 

Caution Phosgene is highly toxic. Part B should be performed in an efficient hood. For a warning regarding the use of benzene, see ref. 2. 

A/,/V-Dimethylaminomethylenemalonate (329, R = Me) was obtained in 81% yield from the reaction of diethyl malonate and its sodium derivative with DMF and phosgene in benzene at 60-70°C for 2 hr (61CB2278). 

Dimethyl and diethyl (l-methylpyrrolidin-2-ylidene)malonates (e.g., Scheme 38,467, n = 0, R = R1 = Me, Et R2 = H R4 = Me) and diethyl (l-methyl-l,2-dihydroquinolin-2-ylidene)malonate were obtained in 30-52% yields when l-methylpyrrolidin-2-one and 1-methyl-1,2-dihydroquinolin-2-one were first reacted with phosgene and then with dialkyl malonates in the presence of triethylamine in benzene at 60°C (61CB2278 69JA6683). 

The phase-transfer catalysed reaction of alkyl halides with potassium carbonate in dimethylacetamide, or a potassium carbonate/potassium hydrogen carbonate mixture in toluene, provides an excellent route to dialkyl carbonates without recourse to the use of phosgene [55, 56], An analogous reaction of acid chlorides with sodium hydrogen carbonate in benzene, or acetonitrile, produces anhydrides (3.3.29.B, >80%), although there is a tendency in acetonitrile for aliphatic acid chlorides to hydrolyse yielding the acids [57]. 

This procedure is a modification of preparations of 3-phen)d, sydnone described earlier. The dehydration of N-nitroso-N phenylglycine has also been effected by the use of thionyl chloride and pyridine in dioxane, thionyl chloride in ethertrifluoroacetic anhydride in etherand diisopropylcarbodiimide in water or by reaction of the alkali metal salts of N-nitroso-N-phenylglycine with phosgene or benzenesulfonyl chloride in water or with acetyl chloride in benzene. ... 

This reaction is typical for the synthesis of sulfonylureas it is mildly exothermic and proceeds smoothly in a variety of inert aprotic solvents. The product is usually obtained in very high yield, as a fine crystalline precipitate. The sulfonyl isocyanates are readily prepared from the substituted benzene sulfonamides by reaction with phosgene, Fig. 3, in the presence of an alkyl isocyanate, for example, butyl isocyanate in an inert solvent at 120 to 140°C according to the general procedure of H. Ulrich and A. A. R. Sayigh (Ref. 3). 

One of the side effects noted in the clinical use of the sulfonamide antibacterial agents was a diuretic effect caused by inhibition of the enzyme carbonic anhydrase. Attempts to capitalize on this side effect so as to obtain agents with greatly enhanced diuretic activity first met success when a heterocyclic ring was substituted for the benzene ring of the sulfonamide. Treatment of the hydrazine derivative, 151, with phosgene leads... 

The two key isocyanates that are used in the greatest volumes for polyurethane polymers are toluene diisocyanate (TDl) and methylene diphenyl diisocyanate (MDl). Both isocyanates are produced first by nitration of aromatics (toluene and benzene, respectively), followed by hydrogenation of the nitro aromatics to provide aromatic amines. In the case of MDl, the aniline intermediate is then condensed with formaldehyde to produce methylene dianiline (MDA), which is a mixture of monomeric MDA and an oligomeric form that is typical of aniline/formaldehyde condensation products [2]. The subsequent reaction of phosgene with the aromatic amines provides the isocyanate products. Isocyanates can also be prepared by the reaction of aromatic amines with dimethylcarbonate [3, 4]. This technology has been tested at the industrial pilot scale, but is not believed to be practiced commercially at this time. 

In this method, an ale soln of benzene-sulfonic acid(previously standardized with phosgene by weighing the pptd diphenyl-carbamide) is added from a burette to a sample of aniline(or its nitrated compd not jiighvr thsji tctrsnitro-) until the 3ppcufuptcc of a dirty-bluish coloration, when a drop of the reaction mist is placed on a filter paper previously impregnated with amino-/3-naphthol indicator(spot test). This method is not applicable for analysis of penta-nitroani ine(Ref 15)... 

Isatoic anhydride (223 R = H) is easily prepared by passing phosgene into a solution of anthranilic acid in dilute hydrochloric acid (5SOSC(3)488), and clearly this approach can be used to form derivatives substituted in the benzene ring. There is an alternative approach, namely the Baeyer-Villiger oxidation of isatins with hydrogen peroxide in acetic acid (Scheme 100) < 0AG(E)222>. 

Thiobenzophenone has been prepared by the action of thio-phosgene on benzene in the presence of aluminum chloride 1 by the action of phosphorus pentasulfide on benzophenone 2 by the action of alcoholic potassium sulfide on benzophenone dichloride 3 by treating benzophenone dichloride with an alcoholic solution of sodium hydrosulfide 4 and by the action of thioacetic acid on benzophenone dichloride.5... 

Hexanitro-N,N -diphenylurea (hexanitrocarbanilide or st/m-dipicrylurea)120 may be prepared by the nitration of carbanilide (sym-diphenylurea) in one, in two, or in three stages. It is of interest because of its explosive properties and because it supplies one way in which benzene may be converted into an explosive which is valuable both for military and for civil uses. Carbanilide may be prepared by the interaction of aniline and phosgene but is most conveniently and economically procured by heating aniline and urea together at 160-165°. 

Yale and Spitzmiller93 obtained 3-acetyl-2-chloro-4-oxo-4H-pyrido-[1,2-a]pyrimidines in 7-9 , yield by treating 2-acetylacetamidopyridines with phosgene in benzene at room temperature. 

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