Phenolate process

The yield of acetone from the cumene/phenol process is beUeved to average 94%. By-products include significant amounts of a-methylstyrene [98-83-9] and acetophenone [98-86-2] as well as small amounts of hydroxyacetone [116-09-6] and mesityl oxide [141-79-7]. By-product yields vary with the producer. The a-methylstyrene may be hydrogenated to cumene for recycle or recovered for monomer use. Yields of phenol and acetone decline by 3.5—5.5% when the a-methylstyrene is not recycled (21). 

The economics of acetone production and its consequent market position are unusual. Traditional laws of supply and demand cannot be appHed because supply depends on the production of phenol and demand is controUed by the uses of acetone. Therefore, coproduct acetone from the cumene to phenol process will continue to dominate market supply. DeHberate production of acetone from isopropyl alcohol accommodates demand in excess of that suppHed by the phenol process. More than 75% of world and 90% of U.S. production comes from the cumene to phenol process. 

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). 

In the 1930s, the Raschig Co. in Germany developed a different chlorobenzene-phenol process in which steam with a calcium phosphate catalyst was used to hydrolyze chlorobenzene to produce phenol (qv) and HCl (6). The recovered HCl reacts with air and benzene over a copper catalyst (Deacon Catalyst) to produce chlorobenzene and water (7,8). In the United States, a similar process was developed by the BakeHte Division of Union Carbide Corp., which operated for many years. The Durez Co. Hcensed the Raschig process and built a plant in the United States which was later taken over by the Hooker Chemical Corp. who made significant process improvements. 

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. 

Figure 10-15. The Lummus benzoic-acid-to-phenol process. ...

HO.C6H4.S03H, mw 174.17. Three of these acids are known, o-, m-, and p-, but only two of them, o- and p- acids form during the sulfonation of phenol in the manuf of PA by the phenolic process. The formation of small quantities of the m-acid was reported, but not definitely proven... 

Cumox [Cumene oxidation] A process for making acetone and phenol by oxidizing cumene, based on the Hock process. This version was further developed and licensed by UOR Three plants were operating in 1986. UOP now licenses the Allied-UOP Phenol process, which combines the best features of Cumox and a related process developed by the Allied Chemical Corporation. 

One convenient way to classify todays processes for making acetone is to separate them into two categories, by-product and on-purpose. You ll unquestionably recall that acetone is one of the outturns of the cumene-to-phenol process described in Chapter 7. (Approximately 0.6 pounds of acetone are generated for each pound of phenol.) That fails into the category of by-product production because the rate at which acetone is produced is not solely dependent on anticipated acetone demand. Often the demand for... 

Phenol Processes—Anhydrous and Aqueous. The original patent describing utilization of phenol for solvent extraction is dated July 1908 (2). This was followed in 1922 by Polish patents (20) and in 1926 by a British (11) and a German (24) patent. These processes describe the use of phenol, either aqueous or mixed, with a variety of... 

PHENOLATE PROCESS. A process for removing hydrogen sulfide from gas by the use of sodium phenolate. which reacts with the hydrogen sulfide to give sodium hydrosulfide and phenol. This can be reversed by steam heat to regenerate the sodium phenolate. 

Based on FeZSM-5 zeolites, a new one-step phenol process (the AlphOx) has been developed jointly by Solutia Inc. and the Boreskov Institute of Catalysis [82]. The process was successfully tested with a pilot plant constructed at Solutia facilities in Pensacola (Florida). The process runs in an adiabatic reactor with the parameters shown in Table 7.5. It provides a 97-98% yield of phenol, with 100% N20 conversion per pass and a recycle of benzene. A 1% yield of dihydroxybenzenes (DHB) is also obtained. This valuable by-product is mainly hydroquinone. Periodically, the catalyst is subjected to regeneration by buming-off coke deposits. Its lifetime is 1.5 years. More details on the process are given elsewhere [82, 83],... 

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. 

Further, acetone via Wacker chemistry must compete with 2-propanol dehydrogenation and coproduction in the Hock phenol process (48). 

Weinberger R, Sayler K. Separations solutions. Capillary electrophoresis of phenol process streams. Am Lab 2002 34 68. 

Application The Sunoco/UOP phenol process produces high-quality phenol and acetone by liquid-phase peroxidation of cumene. 

Commercial plants The Sunoco/UOP Phenol process is currently used in 11 plants worldwide having total phenol capacity of more than 1 million mtpy. Four additional process units, with a total design capacity of 600,000 mtpy, are in design and construction. 

With over 40 years of continuous technological development, the Kellogg Brown Root (KBR) phenol process features low cumene and energy consumptions, coupled with unsurpassed safety and environmental systems. 

Friedel-Crafts technology and zeolite- or other solid catalyst-based processes are currently used for other aromatic alkylations, in particular for the manufacture of linear alkylbenzenes (LABs) made from C10-C14 olefins (Equation 8), or from the corresponding chloroparaffins and benzene, and also to make m- and p-cymene (isopropyltoluene Equation 9). LABs are used for the production of sulfonate detergents, while cymenes lead to m- and p-cresols through a procedure analogous to that used for the cumene-to-phenol process. 

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. 

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. 

Phenol Processes by Manufacturers ° Chlorobenzene Process In 1000 tons per yr. 

Table XXIV. Economic Comparison of a Number of Phenol Processes"...

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. 

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