Cumene and phenol

The next five chapters cover the Mutt and Jeff petrochemicals (or the Gemini twins if you re too young to remember who Mutt and Jeff were). They re grouped together because they come in pairs. You don t have one without the other. The metaphor is accurate for cumene and phenol, ethyl benzene... 

As in the case of cumene and phenol process starting with benzene, UOP is offering UOP zeolitic cymene process for production of cymenes from toluene using zeolytic catalyst and also isomerization and conversion into m-cymene and p-cymene. m- and p-cymenes are separated into pure meta-cymene and pure para-cymene in UOP cymex process. 

Tables 10.3a and 103b give the/average commercial specifications of cumene and phenol respectively (for chlorination).

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. 

PROPENE The major use of propene is in the produc tion of polypropylene Two other propene derived organic chemicals acrylonitrile and propylene oxide are also starting materials for polymer synthesis Acrylonitrile is used to make acrylic fibers (see Table 6 5) and propylene oxide is one component in the preparation of polyurethane polymers Cumene itself has no direct uses but rather serves as the starting material in a process that yields two valuable indus trial chemicals acetone and phenol... 

Most of the world s acetone is now obtained as a coproduct of phenol by the cumene process, which is used by 21 of 31 producing companies in North America, Western Europe, and Japan. Cumene is oxidi2ed to the hydroperoxide and cleaved to acetone and phenol. The yield of acetone is beheved to average about 94%, and about 0.60—0.62 unit weight of acetone is obtained per unit of phenol (13). 

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. 

Propylene requirements for acrylates remain small compared to other chemical uses (polypropylene, acrylonitrile, propylene oxide, 2-propanol, and cumene for acetone and phenol). Hence, cost and availabihty are expected to remain attractive and new acrylate capacity should continue to be propylene-based until after the turn of the century. 

The best preparative results from autoxidation are encountered when only one relatively reactive hydrogen is available for abstraction. The oxidation of isopropylbenzene (cumene) is carried out on an industrial scale, with the ultimate products being acetone and phenol ... 

Propylene could be used as an alkylating agent for aromatics. An important reaction with great commercial use is the alkylation of benzene to cumene for phenol and acetone production. The reaction is discussed in Chapter 10. 

After an initial distillation to split the coproducts phenol and acetone, each is purified in separate distillation and treating trains. An acetone finishing column distills product acetone from an acetone/water/oil mixture. The oil, which is mostly unreacted cumene, is sent to cumene recovery. Acidic impurities, such as acetic acid and phenol, are neutralized hy caustic injection. Figure 10-7 is a simplified flow diagram of an acetone finishing column, and Table 10-1 shows the feed composition to the acetone finishing column. 

The effect of jumping of the maximal hydroperoxide concentration after the introduction of hydrogen peroxide is caused by the following processes. The cumyl hydroperoxide formed during the cumene oxidation is hydrolyzed slowly to produce phenol. The concentration of phenol increases in time and phenol retards the oxidation. The concentration of hydroperoxide achieves its maximum when the rate of cumene oxidation inhibited by phenol becomes equal to the rate of hydroperoxide decomposition. The lower the rate of oxidation the higher the phenol concentration. Hydrogen peroxide efficiently oxidizes phenol, which was shown in special experiments [8]. Therefore, the introduction of hydrogen peroxide accelerates cumene oxidation and increases the yield of hydroperoxide. 

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. 

Delaney JL, Hughes TW. 1979. Source Assessment Manufacture of Acetone and Phenol from Cumene. Prepared by Monsanto Research Corp., Dayton, OH. EPA-600/2-79-019D. NTIS PB80-150592, 500. 

Most of the benzene used in chemical applications ends up in the manufacturing processes for styrene (covered in Chapter 8), cumene (covered in Chapter 7), and cyclohexane (covered in Chapter 4), Polymers and all sorts of plastics are produced from styrene. Cumene is the precursor to phenol, which ultimately ends up in resins and adhesives, mostly for gluing plywood together. The production of styrene and phenol account for. about 70% of the benzene produced. Cyclohexane, used to make Nylon 6 and Nylon 66, is the next biggest application of benzene. 

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... 

Ketones.have the characteristic -C- signature group imbedded in them. Acetone, CH3COCH3, comes from two different routes. It is a by-product in the cumene to phenol/acetone process. It is the on-purpose product of the catalytic dehydrogenation of isopropyl alcohol. Acetone is popular as a solvent and as a chemical intermediate for the manufacture of MIBK, methyl methacrylate, and Bisphenol A. 

Phenol is the major source of Bakelite and phenol resins, which are utihzed in many commodities worldwide phenol is also used as reagent for syntheses of dyes, medicines and so on. The industrial demand for phenol has increased every year and its production now exceeds 7.2 megaton year 94% of the worldwide production of phenol is processed in the cumene process. The cumene process involves the reaction of benzene with propene on acid catalysts like MCM-22, followed by auto-oxidation of the obtained cumene to form explosive cumene hydroperoxide and, finally, decomposition of the cumene hydroperoxide to phenol and acetone in sulfuric acid (Scheme 10.3) [73],... 

This is not always easy to do, so an alternate acetone source is required. In fact, isopropyl alcohol may become attractive again since cumene can be used to increase octane ratings in unleaded gasoline, and phenol, as a plywood adhesive, has its ups and downs with the housing industry. The percentage distribution of the two methods is given in Table 10.4. 

This molecule is called cumene, and it is easily oxidized to acetone and phenol, both important commodity chemicals,... 

Figure 10-5 Reaction steps to make acetone and phenol by autooxidation of isopropyl benzene (also called cumene).

There is a compelling reason to integrate PMMA and phenol-formaldehyde because the monomers phenol and acetone are both made from cumene oxidation (previous chapter). Therefore, one makes one mole of phenol for every mole of acetone, and a producer would have to sell one of these monomers if he did not have an integrated process to produce both polymers or some other products. 

Figure 11-10 Flowsheet of an integrated process to produce PMMA and phenol-formaldehyde polymers simultaneously starting from methane, propane, and cyclohexane through a cumene intermediate.

Many organics also undergo oxidation of a noncombustion nature to form various commercial products. Such reactions are mostly catalytic and include production of synthesis gas, a mixture of CO and H2, conversion of ethylene to ethylene oxide, and cumene to phenol and acetone. 

Fermentation and distillation techniques for acetone production were replaced starting in the 1950s with the cumene oxidation process (Figure 2.1). In this process, cumene is oxidized to cumene hydroperoxide, which is then decomposed using acid to acetone and phenol. This is the primary method used to produce phenol, and acetone is produced as a co-product in the process, with a yield of about 0.6 1 of acetone to phenol. 

Benzene is alkylated with propylene to yield cumene (qv). Cumene is catalytically oxidized in the presence of air to cumene hydroperoxide, which is decomposed into phenol and acetone (qv). Phenol is used to manufacture caprolactam (nylon) and phenolic resins such as bisphenol A. Approximately 22% of benzene produced in 1988 was used to manufacture cumene. 

---