Phenol ammonolysis

Aromatic amines can be produced by reduction of the corresponding nitro compound, the ammonolysis of an aromatic haUde or phenol, and by direct amination of the aromatic ring. At present, the catalytic reduction of nitrobenzene is the predominant process for manufacture of aniline. To a smaller extent aniline is also produced by ammonolysis of phenol. 

The ammonolysis of phenol (61—65) is a commercial process in Japan. Aristech Chemical Corporation (formerly USS Chemical Division of USX Corporation) currently operates a plant at Ha verb ill, Ohio to convert phenol to aniline. The plant s design is based on Halcon s process (66). In this process, phenol is vapori2ed, mixed with fresh and recycled ammonia, and fed to a reactor that contains a proprietary Lewis acid catalyst. The gas leaving the reactor is fed to a distillation column to recover ammonia overhead for recycle. Aniline, water, phenol, and a small quantity of by-product dipbenylamines are recovered from the bottom of the column and sent to the drying column, where water is removed. 

An alternative way to produce aniline is through ammonolysis of either chlorobenzene or phenol. The reaction of chlorobenzene with aqueous ammonia occurs over a copper salt catalyst at approximately 210°C and 65 atmospheres. The yield of aniline from this route is also about 96% ... 

Ammonolysis of phenol occurs in the vapor phase. In the Scientific Design Co. process (Figure 10-10), a mixed feed of ammonia and phenol is heated and passed over a heterogeneous catalyst in a fixed-bed sys-... 

Because direct glycosidation of 4 with phenols is not possible, indirect methods must be used for the preparation of aryl D-glucofuranosidurono-6,3-lactones (29). In addition, aryl 2,5-di-O-acetyl-D-glucofuranosidurono-6,3-lactones (30), obtained35-37 from the reaction of 1,2,5-tri-0-acetyl-D-glucofuranurono-6,3-lactones with phenols, can only be deacetylated by such multi-step procedures as (1) ammonolysis of 30 to afford aryl D-glucofuranosiduronamides (31), followed by amide hydrolysis and lactonization, 35,37 or (2) reduction of 30 with lithium aluminum hydride, and subsequent oxidation of the intermediate aryl D-glucofuranosides38 (32) (see Scheme 1). 

Preparation of tertiary alkyl esters of carbamic acid by the ammonolysis of mixed phenyl alkyl carbonates to yield alkyl carbamate and phenol [24, 40, 41]. 

In preparation for the eventual removal of the undesired oxygen function at C-10 of 313 via a Birch reduction, the phenol 313 was phosphorylated with diethyl phosphorochloridate in the presence of triethylamine to give 314, which underwent stereoselective reduction with sodium borohydride with concomitant N-deacylation to deliver the amino alcohol 315. N-Methylation of 315 by the Eschweiler-Clarke protocol using formaldehyde and formic acid followed by ammonolysis of the ester group and acetylation of the C-2 hydroxyl function afforded 316. Dehydration of the amide moiety in 316 with phosphorus oxychloride and subsequent reaction of the resulting amino nitrile 317 with LiAlH4 furnished 318, which underwent reduction with sodium in liquid ammonia to provide unnatural (+)-galanthamine. 

The replacement of a nuclear substituent such as hydroxyl (-OH), chloro, (-C1), or sulfonic acid (-S03H) with amino (-NH2) by the use of ammonia (ammonolysis) has been practiced for some time with feedstocks that have reaction-inducing groups present thereby making replacement easier. For example, l,4-dichloro-2-nitrobenzene can be changed readily to 4-chloro-2-nitroaniline by treatment with aqueous ammonia. Other molecules offer more processing difficulty, and pressure vessels are required for the production of aniline from chlorobenzene or from phenol (Fig. 3). 

Aniline can also be produced when phenol is subjected to gas-phase ammonolysis at 200 bar and 425°C in an adiabatic, fixed-bed reactor. This is the Halcon/Scientific Design process. The chemistry is ... 

Aniline can also be made by two other methods. In the first, nitrobenzene is reduced by reaction with scrap iron in the presence of a hydrochloric acid catalyst. The iron is oxidized to the ferrous state, and the coproduct aniline is separated. This route accounts for less than 5 percent of the current aniline production. The other process avoids nitrobenzene entirely and involves the vapor-phase ammonolysis of phenol, using an alumina catalyst. Aniline is formed with dipheny-lamine as a by-product. About 20 percent of the aniline is produced by this route. 

Oxiranes can be opened stereo- and regiospecifically under mild conditions with alcohols, thiols, amines, and acetic acid, with simultaneous activation of the nucleophilic and electrophilic centers on an alumina surface.Diols have been obtained on silica gel in the presence of water " and adsorbed FeCls. On an ion-exchange resin, the opening of oxirane isomers to diols and the separation of the latter, ethanolysis, the reaction with phenol,and catalytic ammonolysis have been described. Hydrolysis and methanolysis catalyzed by Nafion-H, a perfluorinated resinsulfonic acid have been reported. ... 

Derivation By (1) catalytic vapor-phase reduction of nitrobenzene with hydrogen (2) reduction of nitrobenzene with iron filings using hydrochloric acid as catalyst (3) catalytic reaction of chlorobenzene and aqueous ammonia (4) ammonolysis of phenol (Japan). 

Nucleophilic displacement reactions in the solid phase using a reverse approach (e.g. the carboxy acid derivative on resin, and target product as the leaving group) has been undertaken to prepare alcohols and phenols by alcoholysis, saponification, aminolysis or ammonolysis (Figure 15.7). 

Heterogeneous liquid phase, involving two or more immiscible liquids. Examples of this are in the nitration of toluene, hydrolysis of chlorobenzene to phenol, and ammonolysis of ethylene dichloride. 

The ammonolysis of unsaturated carbonyl compounds in the presence of hydrogen is the most exothermic type. Reaction of phenols, alcohols, and halides with ammonia is only slightly exothermic. Aminolysis of alcohols is much more exothermic than the ammonolysis. Reactions of hydrocarbons with ammonia to form nitriles seem to be special cases in that they are extremely endothermic in nature. 

With the availability of relatively inexpensive phenol from the Hock synthesis by cumene oxidation, it has also become economical to produce aniline by gas-phase ammonolysis (400 °C, 200 bar) of phenol. 

Figure 5.35 Process for the continuous production of aniline by gas-phase ammonolysis of phenol...

The ammonolysis of chlorobenzene previously operated by Dow in the USA, analogous to the synthesis of phenol from chlorobenzene, has had no commercial importance for some years. Table 5.8 summarizes the production capacities of the major aniline producer countries it is striking that aniline production is limited to a small number of countries. 

Chlorobenzene was one of the first basic organic chemicals produced on a large scale it was already manufactured in 1909 by United Alkali Co, Wipnes/USA. The importance of chlorobenzene rose dramatically during World War I, since it was needed as an intermediate in the production of phenol for the manufacture of picric acid. Other uses, now principally of historic importance, are the production of DDT (l,l,l-trichloro-2,2-di(4-chlorophenyl)ethane) from chlorobenzene and chloral in the presence of sulfuric add, first synthesized in 1874 by Othmar Zeid-ler, and the ammonolysis to produce aniline. 

Next to phenol the herbicide isoproturon is one of the few cumene derivatives with any large-scale importance. Nitration of cumene yields 2-/4-nitrocumene in the ratio 35 65. The 4-isomer is recovered by vacuum distillation and is then reduced to cumidine (4-isopropylaniline). (Cumidine can also be produced by ammonolysis of 4-isopropylphenol, which arises as a by-product during the oxidation of 1,4-diisopropylbenzene to produce hydroquinone). Cumidine is reacted with phosgene to give 4-isopropylphenyl isocyanate. Reaction of 4-isopropyl-phenyl isocyanate with dimethylamine yields isoproturon, which in Western Europe is produced in quantities of around 6,000 tpa. 

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