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Dow phenol process

The base or nucleophile in the Dow phenol process is aqueous NaOH that needs to be heated to 300° C, which is only possible at a pressure of 200 bar. This conconction is only just capable of deprotonating chlorobenzene to benzyne or of adding to the latter subsequently. Thus, there is no analogous synthesis of diaryl ethers from sodium phenolates and haloben-zenes. And as expected, the product resulting from the Dow process did not contain more than 15% of diphenyl ether. [Pg.251]

Phenol from Chlorobenzene, Dow Process. The Dow phenol processes base on the hydrolysis of chlorobenzene in caustic soda solution at temperatures of about 360°C and pressures of about 4,000 psi. Although the basic reaction was discovered in 1914 by Meyer and Bei us, the jdevelop-ment of the commercial application of the reaction had to await the introduction of satisfactoiy materials of construction and the solution of a number of chemical and chemical engineering problems. [Pg.798]

Often, the compound to be oxidized is made a ligand, and the oxidation can then be intramolecular, as in the Dow phenol process [Eq. (53)], where the benzoate of basic copper(II) benzoate is oxidized to salicylate by hydroxide and then carbon dioxide is eliminated to yield phenol. [Pg.80]

In the Hquid-phase process, both benzaldehyde and benzoic acid are recovered. This process was iatroduced and developed ia the late 1950s by the Dow Chemical Company, as a part of their toluene-to-phenol process, and by Snia Viscosa for their toluene-to-caprolactam process. The benzaldehyde recovered from the Hquid-phase air oxidation of toluene may be purified by either batch or continuous distillation. Liquid-phase air oxidation of toluene is covered more fully (see Benzoic acid). [Pg.34]

Although Dow s phenol process utilized hydrolysis of the chlorobenzene, a reaction studied extensively (9,10), phenol production from cumene (qv) became the dominant process, and the chlorobenzene hydrolysis processes were discontinued. [Pg.46]

Dow-Phenol A process for making phenol by oxidizing molten benzoic acid with atmospheric oxygen. The catalyst is cuprous benzoate. [Pg.90]

An interesting new homogeneous catalytic process was developed by Buijs [184] for the reductive dehalogenation of polychlorinated and -brominated aromatic hydrocarbons and ethers. Cu(I) benzoate catalyzed the reaction under Dow-Phenol conditions in the absence of air at 235 °C (Eq. (8)) ... [Pg.533]

Let us recall that by the sol-gel method one can obtain very efficiently very well-defined systems such as Ti silicalite, which can be considered as a single site system where titanium is tetracoordinated in a zeolitic matrix and undergoes epoxidation of propylene or hydroxylahon of benzene to phenol. Bear in mind that it took industry more than 20 years to realize such an industrial processes (Dow-BASF process) [1]). [Pg.76]

Pertinent patents dealing with the toluene-to-phenol process are listed in Table XXL It is difficult to judge, based on the published literature alone, which of the processes described in the patents are practiced. According to a recent article, Dow Chemical Co. apparently manufactures phenol by processes described in their own patents as well as by some California Research Corp. patents licensed to Dow (8). A schematic flowsheet illustrating the technical execution of the process is given in Figure 3. [Pg.88]

An economical evaluation of phenol processes is complicated by the number and variety of competing processes. Table XXII compares some key features of various phenol processes, based on two excellent, recent reviews (4,15). Hay et al. (15) point out that synthetic phenol processes currently account for 98% of the phenol produced in the United States and Canada. The various phenol processes currently used are listed in Table XXIII. An economic comparison between a number of phenol processes is given in Table XXIV. Based on this table, the Raschig, Cumene, and Dow toluene processes are equivalent with regard to return price. Therefore, selection must be made on the basis of other factors, such as value of intermediates and by-products, ease of operation, and initial investment. [Pg.89]

Acetophenone (phenyl methyl ketone) has a wide range of applications in perfumery. It can be recovered from the heavy byproduct stream of a phenol process (which otherwise has fuel value) using the process described in U.S. 4,559,110 assigned to Dow Chemical. It can be made by oxidation of ethylbenzene using the process described in U.S. 4,950,794 (to Arco Chemical Technology). It can also be produced as a natural product by fermentation of cinnamic acid using the process described in U.S. 6,482,794 (to International Elavors Fragrances). Estimate the cost of production via each route. [Pg.1162]

UOP is offering the technology for conversion of cumene to phenol and acetone based on UOP/Allied (Now Mobil) phenol process. Similarly, Kellog is offering the technology of Hercules and lately Dow-Mousanto Process. [Pg.32]

Obtained synthetically by one of the following processes fusion of sodium ben-zenesulphonate with NaOH to give sodium phenate hydrolysis of chlorobenzene by dilute NaOH at 400 C and 300atm. to give sodium phenate (Dow process) catalytic vapour-phase reaction of steam and chlorobenzene at 500°C (Raschig process) direct oxidation of cumene (isopropylbenzene) to the hydroperoxide, followed by acid cleavage lo propanone and phenol catalytic liquid-phase oxidation of toluene to benzoic acid and then phenol. Where the phenate is formed, phenol is liberated by acidification. [Pg.303]

Synthetic phenol capacity in the United States was reported to be ca 1.6 x 10 t/yr in 1989 (206), almost completely based on the cumene process (see Cumene Phenol). Some synthetic phenol [108-95-2] is made from toluene by a process developed by The Dow Chemical Company (2,299—301). Toluene [108-88-3] is oxidized to benzoic acid in a conventional LPO process. Liquid-phase oxidative decarboxylation with a copper-containing catalyst gives phenol in high yield (2,299—304). The phenoHc hydroxyl group is located ortho to the position previously occupied by the carboxyl group of benzoic acid (2,299,301,305). This provides a means to produce meta-substituted phenols otherwise difficult to make (2,306). VPOs for the oxidative decarboxylation of benzoic acid have also been reported (2,307—309). Although the mechanism appears to be similar to the LPO scheme (309), the VPO reaction is reported not to work for toluic acids (310). [Pg.345]

Toluene—Benzoic Acid Process. The toluene—benzoic acid process was first introduced by Dow-Canada, Ltd. in 1961 (13). It accounts for 4% of the total synthetic phenol capacity in the world. [Pg.289]

Production of a-methylstyrene (AMS) from cumene by dehydrogenation was practiced commercially by Dow until 1977. It is now produced as a by-product in the production of phenol and acetone from cumene. Cumene is manufactured by alkylation of benzene with propylene. In the phenol—acetone process, cumene is oxidized in the Hquid phase thermally to cumene hydroperoxide. The hydroperoxide is spHt into phenol and acetone by a cleavage reaction catalyzed by sulfur dioxide. Up to 2% of the cumene is converted to a-methylstyrene. Phenol and acetone are large-volume chemicals and the supply of the by-product a-methylstyrene is weU in excess of its demand. Producers are forced to hydrogenate it back to cumene for recycle to the phenol—acetone plant. Estimated plant capacities of the U.S. producers of a-methylstyrene are Hsted in Table 13 (80). [Pg.491]

Benzaldehyde is produced ia the United States by Kalama Chemical Incorporated, Kalama, Washington and ia Canada by Chatterton Petrochemical Corporation, Delta, British Columbia. Both plants were constmcted by The Dow Chemical Company ia the early 1960s to produce phenol from benzoic acid and both produce benzaldehyde as a by-product of that process (6). Production and sales figures for benzaldehyde are not available. [Pg.34]

In the United States all other processes have been completely phased out and virtually all benzoic acid is manufactured by the continuous hquid-phase air oxidation of toluene. In the late 1950s and the early 1960s both Dow Chemical and Snia Viscosa constmcted faciUties for Hquid-phase toluene oxidation because of large requirements for benzoic acid in the production of phenol and caprolactam. Benzoic acid, its salts, and esters are very useful and find appHcation in medicinals, food and industrial preservatives, cosmetics, resins, plasticizers, dyestuffs, and fibers. [Pg.52]

Caprolactam. At the same time that Dow was constmcting toluene to phenol plants, Snia Viscosa (28—30) introduced two processes for the manufacture of caprolactam (qv) from benzoic acid. The earlier process produced ammonium sulfate as a by-product, but the latter process did not. In either process benzoic acid is hydrogenated to cyclohexanecarboxyHc acid [98-89-5] which then reacts with nitrosylsulfuric acid to form caprolactam [105-60-2]. [Pg.55]

The Dow Chemical Company in the mid-1920s developed two processes which consumed large quantities of chlorobenzene. In one process, chlorobenzene was hydrolyzed with ammonium hydroxide in the presence of a copper catalyst to produce aniline [62-53-3J. This process was used for more than 30 years. The other process hydrolyzed chlorobenzene with sodium hydroxide under high temperature and pressure conditions (4,5) to product phenol [108-95-2]. The LG. Earbenwerke in Germany independentiy developed an equivalent process and plants were built in several European countries after World War II. The ICI plant in England operated until its dosing in 1965. [Pg.46]

Other routes for the preparation of phenol are under development and include the Dow process based on toluene. In this process a mixture of toluene, air and catalyst are reacted at moderate temperature and pressure to give benzoic acid. This is then purified and decarboxylated, in the presence of air, to phenol (Figure 23.5). [Pg.637]

Phenol was manufactured for many years by the Dow process, in which chlorobenzene reacts with NaOH at high temperature and pressure (Section 16.S). Now, however, an alternative synthesis from isopropylbenzene, commonly called... [Pg.628]

Examples for necessary process improvements through catalyst research are the development of one-step processes for a number of bulk products like acetaldehyde and acetic acid (from ethane), phenol (from benzene), acrolein (from propane), or allyl alcohol (from acrolein). For example, allyl alcohol, a chemical which is used in the production of plasticizers, flame resistors and fungicides, can be manufactured via gas-phase acetoxylation of propene in the Hoechst [1] or Bayer process [2], isomerization of propene oxide (BASF-Wyandotte), or by technologies involving the alkaline hydrolysis of allyl chloride (Dow and Shell) thereby producing stoichiometric amounts of unavoidable by-products. However, if there is a catalyst... [Pg.167]

Organic carboxylic acids are commonly found in foods, in the adipate process stream, and as pollutants. Fatty acids are the lipophilic portion of glycerides and a major component of the cell membrane. Phenols are widely used in polymers, as wood preservatives, and as disinfectants. Chloro-phenols such as 4-chlorophenol, two isomeric dichlorophenols, 2,4,6-tri-chlorophenol, three isomeric tetrachlorophenols, and pentachlorophenol were separated on a Dowex (The Dow Chemical Co. Midland, MI) 2-X8 anion exchange resin using an acetic acid-methanol gradient.138... [Pg.233]

The Dow Process utilizes an elimination/addition reaction to convert chlorobenzene to phenol. The proposed mechanism for this reaction is shown in Figure 8-3. The high-temperature reaction begins with chlorobenzene and aqueous sodium hydroxide. Note that this mechanism starts with the hydroxide attacking as a base, beginning dehydrohalogenation to form benzyne. The second hydroxide ion attacks as a nucleophile to form a carbanion intermediate, which behaves as a base in the last step to yield the final product. [Pg.114]

Phenol can also be prepared by the decomposition of benzoic acid prepared by the oxidation of toluene.927,978 The process is an oxidative decarboxylation catalyzed by copper(II). An interesting feature of this reaction is that the phenolic hydroxyl group enters into the position ortho to the carboxyl group as was proved by 14C labeling.979 In the Dow process980 molten benzoic acid is transformed with steam and air in the presence of Cu(II) and Mg(II) salts at 230-240°C. A copper oxide catalyst is used in a vapor-phase oxidation developed by Lummus.981... [Pg.513]

In time of war the industries of a country strive to produce as much toluene as possible. The effort results in the production also of increased quantities of other aromatic hydrocarbons, particularly of benzene, and these become cheaper and more abundant. Every effort is made to utilize them profitably for military purposes. As far as benzene is concerned, the problem has been solved through chlorobenzene, which yields aniline and phenol by the Dow process, and hence picric acid, and which gives dinitro-chlorobenzene on nitration which is readily convertible, as will be described later, into picric acid and tetryl and several other... [Pg.131]

Steam and silica gel to produce phenol from chlorobenzene, the Dow process with steam and a copper salt catalyst, etc. [Pg.140]

Benzoic acid is an important chemical intermediate which can also be used as a phenol precursor by decarbonylation in the presence of copper catalysts (Lummus process). It is produced industrially by oxidation of toluene by air in the presence of cobalt catalysts (Dow and Amoco processes equation 240). The reaction can be carried out without solvent, or in an acetic acid solvent. The oxidation of toluene without solvent uses a cobalt octoate catalyst and operates at higher temperature (180-200 CC). Yields of benzoic acid are about 80% for ca. 50% toluene conversion.361 In an acetic acid solution and in the presence of cobalt acetate, the reaction occurs at lower temperature conditions (110-120 °C) and gives higher yields in benzoic acid (90%).83,84... [Pg.386]

You can prepare phenols in large quantities by the pyrolysis of the sodium salt of benzene sulfonic acid, by the Dow process, and by the air oxidation of cumene. Each of these processes is described below. You can also prepare small amounts of phenol by the peroxide oxidation of phenylboronic acid and the hydrolysis of diazonium salts. [Pg.58]

The addition-elimination mechanism for nucleophilic aromatic substitution requires strong electron-withdrawing substituents on the aromatic ring. Under extreme conditions, however, unactivated halobenzenes react with strong bases. For example, a commercial synthesis of phenol (the Dow process ) involves treatment of chlorobenzene with sodium hydroxide and a small amount of water in a pressurized reactor at 350 °C ... [Pg.788]


See other pages where Dow phenol process is mentioned: [Pg.866]    [Pg.863]    [Pg.866]    [Pg.863]    [Pg.5]    [Pg.55]    [Pg.10]    [Pg.133]    [Pg.11]    [Pg.55]    [Pg.130]    [Pg.261]    [Pg.12]    [Pg.1263]   
See also in sourсe #XX -- [ Pg.251 ]




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