Carbanilide

The insoluble residue of diphenylurea from the original filtration is chemically almost pure. It may be recrystallised from hot rectified spirit or ethanol, a process which will be necessary if the material contains fragments of porcelain. When using either of these solvents, however, the hot solution should be filtered at the pump using a small Buchner funnel and flask which again have been preheated by the filtration of some of the hot solvent, as the solution when cooled rapidly deposits the diphenylurea. iSym-Diphenylurea (or carbanilide) is thus obtained as fine colourless crystals, m.p. 237° yield, 1-1 5 S ... 

Note.—Esters of carbamic acid upon boiling with aniline yield carbanilide (m.p. 238°), ammonia and the corresponding alcohol. 

Carbanilide ( 3fin-diphenylurea) [102-07-8] M 212.3, m 242 . Crystd from EtOH or a large volume (40mL/g) of hot water. 

Hydantoins have been prepared starting from aminoesters that were first transformed into the corresponding carbanilides (ureas) 144 under standard conditions and then cyclized under microwave irradiation in the presence of Ba(OH)2 in DMF in 2 min and in yields ranging from 91 to 80% (Scheme 51) [91,92], Simple and more complex hi- and tricyclic compounds, such as 145-147, have been prepared with this method that seems versatile and applicable to many substrates. 

The CO-transfer reaction onto o-aminophenol or o-phenylenediamine by GDI has been used as a method for converting /Mactam carbanilides, obtained by a 4-component condensation, into the corresponding carboxylic acids without damaging the sensitive fi-lactam moiety. The method has its basis in the production of easily cleavable compounds from o-hydroxy- and o-aminoanilides and CDI [76]... 

Scheme 7.S0 Intramolecular carbanilide cyclization on a solid support.

Die Verbindung kann man durch Nitrierung von Carbanilid in einer Oder mehreren Stufen gewinnen. 

Air (phosgene) Phosgene collection in an impinger containing a solution of aniline (forming carbanilide) evaporation of solvent dissolution of residue in acetonitrile HPLC/UV (EPA Method T06) 0.1 ppb (v/v) 100 at 3 ppb (v/v) 15% RSD EPA 1988n... 

Chloroformates can interfere in the carbanilide analysis (EPA 1988n). In the method of Rando et al. (1993), the apparent recovery of phosgene was nearly quantitative from air at up to 25% relative humidity this decreased to about 65% at 95% humidity. 

Uses Manufacture of viscose rayon, cellophane, flotation agents, ammonium salts, carbon tetrachloride, carbanilide, paints, enamels, paint removers, varnishes, tallow, textiles, rocket fuel, soil disinfectants, electronic vacuum tubes, herbicides grain fumigants solvent for fats, resins, phosphorus, sulfur, bromine, iodine, and rubber petroleum and coal tar refining solvent and eluant for organics adsorbed on charcoal for air analysis. 

Chlorotrifluoromethyl aniline (no. 73.) was found in the sediment samples. This compound is used as a reactant with chloro-aniline (no. 72) in the preparation of 4,4 -dichloro-3-(trifluoromethyl)-carbanilide, a disinfectant. Two other related compounds also found in some of the sediments were chlorophenyl isocyanate (no. 74) and chloro(-trifluoromethyl)phenyl isocyanate (no. 75). This suggests that some of the 4,4 -dichloro-3-(trifluoromethyl)-carbanilide may, in fact, exist in the sediment extracts but is decomposed in the injection port of the gas chromatograph, since it is very doubtful that the easily hydrolyzable isocyanates exist as such in the sediments. To strengthen this hypothesis some 3,4,4 -trichlorocarbanilide [none of the 4,4 -dichloro-3-(trifluorome-thyl)-carbanilide was available] was analyzed by GCMS. The injection port temperature was 300°C. As expected, none of the parent compound eluted from the column. However, mass spectra were obtained for chlorophenyl isocyanate, dichlorophenyl isocyanate, chloroaniline, and dichloroaniline. The presence of the carbanilides themselves (no. 76, 77, 78) was confirmed with the help of HPLC and mass spectral identification. 

The sediment concentrations of anthropogenic compounds in the cove were somewhat less variable than upstream this probably reflects the greater bottom uniformity of the cove. Fewer of the plant s compounds were detected in sediment from the channel where the cove leads into the brackish river (Point 18, Figure 1). Found at this location were various phenols (no. 28, 30a, 30b, 31, 33, 38, 39), di-t-butyl-benzoqui-none (no. 57), 3,5-di-t-butyl-4-hydroxy-benzaldehyde (no. 35), three benzotriazoles (no. 6, 10, 12), 4,4 -dichloro-3(trifluoromethyl) carbanilide (no. 77), and 2-chloro-4,6-bis-isopropylamino-s-triazine (no. 14). The only compounds from the plant detected in the sediment sample from the brackish river (Point 19) were the two high molecular weight benzotriazoles (no. 10 and 12) and methyl 3-(3 ,5 -di-t-butyl-4 -hydroxphenyl) propionate (no. 46). 

The crude carbanilide (symmetrical diphenylurea) is practically pure, and may be obtained in large colorless needles melting at 2350 by recrystallization from alcohol with the use of decolorizing carbon 1 l. of alcohol is required for every 25 g. of... 

The reaction can undoubtedly be explained by the formation of an equilibrium mixture of urea and ammonium cyanate in boiling solution the ammonium cyanate reacts at the moment of its formation with aniline hydrochloride, yielding phenylurea. This latter compound also undergoes a secondary reaction, involving the intermediate formation of phenyl isocyanate, which reacts with aniline hydrochloride forming carbanilide so that in order to obtain the best yield it is necessary to interrupt the process from time to time and remove the phenylurea first formed. 

The carbanilide can also be obtained in long needles from glacial acetic acid or preferably ethyl acetate. 

Of the various published methods of preparing phenylurea, such as treatment of aniline salts with potassium cyanate in water solution,1 heating aniline with urea,2 with cyanic acid,3 or with cyanogen chloride,4 and the interaction of phenyl isocyanate or phenylcarbamine chloride with ammonia,5 the only ones to be considered as practical methods for preparation are the first two. The first suffers from the disadvantage that potassium cyanate is not easily prepared in the laboratory and rapidly undergoes spontaneous decomposition in storage while by the action of urea on aniline alone, carbanilide is formed in rather larger proportion than phenylurea. 

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