Chemical manufacturing, chemicals used cumene

The propylene equivalent of polyethylene is polypropylene. About 50% of the chemical use of propylene is directed to that use. Other major applications are the manufacture of propylene oxide, isopropyl alcohol, cumene, 0X0 alcohols, acrylic acids, and acrylonitrile. The consumer products you are familiar with show up everywhere carpets, rope, clothing, plastics in automobiles, appliances, toys, rubbing alcohol, paints, and epoxy glue. 

As we learned in Chapter 8, the official production of propylene is usually about half that of ethylene, only because a large part of the propylene is used by petroleum refineries internally to alkylate gasolines. This captive use is not reported. Of the propylene used for chemical manufacture, nearly 40% is polymerized to polypropylene, to be discussed in a later chapter. Of the remaining amount of propylene, seven chemicals from the top 50 are manufactured. These are listed in Table 10.1. Their industrial manufacturing methods are summarized in Fig. 10.1. Note that four of these chemicals, cumene, phenol, acetone, and bisphenol A, are also derived from a second basic organic chemical, benzene. 

For many years, phenol was manufactured b the Dow process, in which chlorobenzene reacts with NaOH at high temperature and pressure (Section 16.9). Now, however, an alternative synthesis from isopropylbenzene (cumene) is used. Cumene reacts with air at high temperature by a radical mechanism to form cumene hydroperoxide, which is converted into phenol and acetone by treatment with acid. This is a particularly efficient process because two valuable chemicals are prepared at the same time. 

AI3-03976 Asymmetrical trimethylbenzene Benzene, 1,2,4-trimethyl- Benzene, 1,2,5-trimethyl- EINECS 202-436-9 HSDB 5293 NSC 65600 Pseudocumene Pseudocumol psi-Cumene as-Trimelhylbenzene Uns-trimethylbenzene. Used as a solvent in chemical manufacturing and in scintillation counters. Oil mp = -43.8° bp = 169.3° d O = 0.8578 Xm = 267, 277 nm (MeOH) insoluble in H2O, freely soluble in EtOH, EtzO, MezCO, CsHe, CCI4, petroleum ether. 

Small amounts of cumene are used as thinners for paints, lacquers, and enamels, and as solvents in paints and other types of coatings. By far the greatest amount of cumene, however, is used as a raw material in the manufacture of phenol, acetone, and methyl styrene. These compounds, in turn, have a great many chemical and industrial uses. Some of the most important uses are the production of plastics, such as polystyrene, phenol-formaldehyde resins, and polycarbonates. 

Vernon Krieble, chairman of the Chemistry Department at Trinity College in Hartford, Connecticut, learned about the product through his son, Robert Krieble, who was employed at General Electric. Vernon Krieble found a chemical solution to the problem by using cumene hydroperoxide (I) (see Section XII for all structures) as the initiator and packaging in half-filled oxygen-permeable polyethylene bottles [8]. He licensed the GE patent and in 1954 founded the American Sealants Corporation, which later became Loctite Corporation [9]. At the present time anaerobic adhesives and sealants are manufactured or sold on every continent by more than a dozen companies. Applications in virtually every industry, and technological iimovation, as measured by patent activity, continue unabated. 

In addition. Cooper et al. [91] discussed the use of a Raman analyzer to provide feedback and feed-forward data on a number of chemical manufacturing processes originating from crude oil, where several of the production steps involved a distillation separation again, in these examples, the Raman analyzer was positioned at the outlet to the distillation tower. They claim from their work that a Raman analyzer would be useful for monitoring and controlling aromatic extraction, liquid paraffin aromatization, and the production of cumene, cyclohexane from benzene, ethylbenzene, xylene isomers, dimethyl terphthalate, and styrene. It should also be noted that in all these processes, at least one and in several cases multiple distillation columns are involved. 

Benzene was first isolated by Faraday in 1825 from the liquid condensed by compressing oil gas. It is the lightest fraction obtained from the distillation of the coal-tar hydrocarbons, but most benzene is now manufactured from suitable petroleum fractions by dehydrogenation (54%) and dealkylation processes. Its principal industrial use is as a starting point for other chemicals, particularly ethylbenzene, cumene, cyclohexane, styrene (45%), phenol (20%), and Nylon (17%) precursors. U.S. production 1979 2-6 B gals. 

Worldwide propylene production and capacity utilization for 1992 are given in Table 6 (74). The world capacity to produce propylene reached 41.5 X 10 t in 1992 the demand for propylene amounted to 32.3 x 10 t. About 80% of propylene produced worldwide was derived from steam crackers the balance came from refinery operations and propylene dehydrogenation. The manufacture of polypropylene, a thermoplastic resin, accounted for about 45% of the total demand. Demand for other uses included manufacture of acrylonitrile (qv), oxochemicals, propylene oxide (qv), cumene (qv), isopropyl alcohol (see Propyl alcohols), and polygas chemicals. Each of these markets accounted for about 5—15% of the propylene demand in 1992 (Table 7). 

Benzoic Acid. Ben2oic acid is manufactured from toluene by oxidation in the liquid phase using air and a cobalt catalyst. Typical conditions are 308—790 kPa (30—100 psi) and 130—160°C. The cmde product is purified by distillation, crystallization, or both. Yields are generally >90 mol%, and product purity is generally >99%. Kalama Chemical Company, the largest producer, converts about half of its production to phenol, but most producers consider the most economic process for phenol to be peroxidation of cumene. Other uses of benzoic acid are for the manufacture of benzoyl chloride, of plasticizers such as butyl benzoate, and of sodium benzoate for use in preservatives. In Italy, Snia Viscosa uses benzoic acid as raw material for the production of caprolactam, and subsequendy nylon-6, by the sequence shown below. 

AH commercial processes for the manufacture of caprolactam ate based on either toluene or benzene, each of which occurs in refinery BTX-extract streams (see BTX processing). Alkylation of benzene with propylene yields cumene (qv), which is a source of phenol and acetone ca 10% of U.S. phenol is converted to caprolactam. Purified benzene can be hydrogenated over platinum catalyst to cyclohexane nearly aH of the latter is used in the manufacture of nylon-6 and nylon-6,6 chemical intermediates. A block diagram of the five main process routes to caprolactam from basic taw materials, eg, hydrogen (which is usuaHy prepared from natural gas) and sulfur, is given in Eigute 2. 

Cumene as a pure chemical intermediate is produced in modified Friedel-Crafts reaction processes that use acidic catalysts to alkylate benzene with propylene (see Alkylation Friedel-CRAFTSreactions). The majority of cumene is manufactured with a soHd phosphoric acid catalyst (7). The remainder is made with aluminum chloride catalyst (8). 

At one time the requirement for phenol (melting point 41°C), eould be met by distillation of eoal tar and subsequent treatment of the middle oil with eaustic soda to extraet the phenols. Such tar acid distillation products, sometimes containing up to 20% o-cresol, are still used in resin manufacture but the bulk of phenol available today is obtained synthetically from benzene or other chemicals by such processes as the sulphonation process, the Raschig process and the cumene process. Synthetic phenol is a purer product and thus has the advantage of giving rise to less variability in the condensation reactions. 

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. 

Chlorobenzene. Chlorobenzene is an important solvent and intermediate in the production of chemicals and dyes. Its use in phenol manufacture, however, was superseded by the introduction of the cumene process. 

Cumene a colorless liquid [C6H5CH (CH3)2] used as an aviation gasoline blending component and as an intermediate in the manufacture of chemicals. 

Propene is used for the manufacture of a variety of chemicals (Fig. 2), including polypropylene, acrylic acid, Ao-propyl alcohol, cumene, propy-... 

Isopropylbenzene, also known as cumene, is among the top commodity chemicals, taking about 7-8% from the total worldwide propylene consumption. Today, the cumene is used almost exclusively for manufacturing phenol and acetone. 

Cumene manufacture consumed about 10 percent (2.2 billion lb) of the propylene used for chemicals in the United States in 1998. It is prepared in near stoichiometric yield from propylene and benzene with acidic catalysts (scheme below). Many catalysts have been used commercially, but most cumene is made using a solid phosphoric acid catalyst. Recently, there has been a major industry shift to zeolite-based catalyst. The new process has better catalyst productivity and also eliminates the environmental waste from spent phosphoric acid catalyst. It significantly improves the product yield and lowers the production cost. Cumene is used almost exclusively as feed to the cumene oxidation process, which has phenol and acetone as its coproducts. 

Benzene found in the environment is from both human activities and natural processes. Benzene was first discovered and isolated from coal tar in the 1800s. Today, benzene is made mostly from petroleum sources. Because of its wide use, benzene ranks in the top 20 in production volume for chemicals produced in the United States. Various industries use benzene to make other chemicals, such as styrene (for Styrofoam and other plastics), cumene (for various resins), and cyclohexane (for nylon and synthetic fibers). Benzene is also used for the manufacturing of some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Natural sources of benzene, which include volcanoes and forest fires, also contribute to the presence of benzene in the environment. Benzene is also a part of crude oil and gasoline and cigarette smoke. For more information on the nature and uses of benzene, see Chapters 3 and 4. 

Zeolite-based processes have gradually displaced conventional ones, involving supported H3P04 or A1C13 as catalysts, in the manufacture of cumene, the raw material for phenol production [1, 6, 39]. A three-dimensional dealuminated mordenite (3-DDM) catalyst was developed by Dow Chemical for this purpose [39]. Dealumination, using a combination of acid and thermal treatments, increases the Si/Al ratio from 10-30 up to 100-1000 and, at the same time, changes the total pore volume and pore-size distribution of the mordenite. The... 

The catalyst used is a commercial catalyst known as the super-D manufactured by Crosfield Chemicals Ltd., UK. It is in the form of particulate spheroid with an average diameter of 81 microns and consists of 15-18% ion exchanged Re sodium Y-zeolites on a support silica-alumina matrix. Heat treatment of catalyst particles at 150°C for 48 hours is undertaken before cracking reaction commenced. The isopropyl benzene (cumene) has the purity higher than 99.5% which was supplied by Fissons Scientific Apparatus. 

Use Manufacture of isopropyl alcohol, polypropylene, synthetic glycerol, acrylonitrile, propylene oxide, heptene, cumene, polymer gasoline, acrylic acid, vinyl resins, oxo chemicals. 

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