Benzene, production volume

Older methods use a liquid phase process (Figure 10-11). ° New gas-phase processes operate at higher temperatures with noble metal catalysts. Using high temperatures accelerates the reaction (faster rate). The hydrogenation of benzene to cyclohexane is characterized by a highly exothermic reaction and a significant decrease in the product volume... 

For purification the still yellow crude product is dissolved in very little warm benzene, four volumes of light petrol are added, and crystallisation is induced by cooling in ice and stirring with a glass rod. The crystals are washed with cold petrol ether. 

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. 

Production, Import/Export, Use, and Release and Disposal. In 1994, benzene was the 17th highest volume chemical produced in the United States, compared to the 18th and 17th ranks in 1993 and 1992, respectively (C EN 1994 Kirschner 1995 Reisch 1994). In 1994, the U.S. production volume of... 

Today a great variety of chemicals can contaminate sources of drinking-water. By far the most frequent contaminants in this category are trichloroethylene and tetrachloroethylene because of their large production volumes and widespread use in industry. Other chemicals that occur less frequently or at lower concentrations include dichloromethane, carbon, tetrachloride, chloroethylene (i.e. vinyl chloride), the 3 possible isomers of dichloroethylene, dichloroethane, 1,2,-dibromoethane, l,2-dibromo-3-chloropropane, and benzene. 

The industrial alkylation of aromatics with olefins is one of the major examples of development of environmentally friendly processes with solid acid catalysts [221, 222]. The principal products obtained are ethylbenzene (EB), cumene (CUM), p-diethylbenzene, p-diisopropylbenzene, Cio-Ci4linear alkylbenzenes (LAB) and cymene. Figure 2.28 summarizes several aromatic alkylations industrially applied for the preparation of important chemical intermediates [222]. These reactions include the most important aromatic substrates, benzene, toluene and xylene, and different olefins. They also include two different kinds of alkylation electrophilic alkylation on the aromatic ring catalyzed by acids and side-chain alkylation catalyzed by bases. In terms of production volume, add-catalyzed alkylations are by far the most... 

Production of EPS. Plastic materials on the polystyrene basis occupy with its production volume the third position in the world, following polyolefin and pol5rvinyl chloride. Polystyrene (PS) is made from styrene (vinyl benzene), which is liquid at ordinary temperatures and can be polymerized well in a unit or suspension. In the basic methylene chain, which forms a polystyrene molecule, a six-part aromatic circle (phenyl) is linked to every other carbon instead of hydrogen. 

At present succinic acid is a specialty chemical with an annual production volume of about 30 000 tons worldwide. Fossil-based succinic acid is most commonly prepared via hydrogenation of maleic anhydride (by oxidation of n-butane or benzene) [73]. In the field of bio-based chemicals and building blocks succinic acid is considered to be one of the most important platform chemicals [1, 74, 75], and as a result of the introduction of biosuccinic acid the production volume is expected to double or triple within years. Several fermentation processes have been described to produce bio-based succinic acid. Common feedstocks for these processes include glucose, starch and xylose [76]. The commercial potential for bio-succinic acid is illustrated by the numerous initiatives by companies that are working towards, or already... 

In the United States, CAS number 88-73-3, Benzene, l-chloro-2-nitro-, is listed on the Toxic Substances Control Act (TSCA) Non-Confidential Inventory with no Significant New Use Rule (SNUR) [38]. It has been designated as a High Production Volume (HPV) chemical [39]. In the European Union (EU), ONCB has been notified under REACH as an intermediate and as a chemical produced or imported at 100-1,000 tormes per armum. The REACH notifications refer to use as an intermediate in closed processes, and to use as a laboratory reagent [40]. In China, ONCB is listed on the Inventory of Existing Chemical Substances Produced or Imported in China (lESC) it is also listed in the Catalog of Hazardous Chemicals [41]. 

Why is potassium aluminium sulphate not soluble in benzene A compound M has the composition C = 50.0% H=12.5%o A1 = 37.5%. 0.360 g of M reacts with an excess of water to evolve 0.336 1 of gas N and leave a white gelatinous precipitate R. R dissolves in aqueous sodium hydroxide and in hydrochloric acid. 20 cm of N require 40 cm of oxygen for complete combustion, carbon dioxide and water being the only products. Identify compounds N and R, suggest a structural formula for M, and write an equation for the reaction of M with water. (All gas volumes were measured at s.t.p.)... 

Dissolve 57 g. of dry malonic acid in 92 5 ml. of dry P3rridine contained in a 500 ml. round-bottomed flask, cool the solution in ice, and add 57 g. (70 ml.) of freshly distilled n-heptaldehyde (oenanthol) with stirring or vigorous shaking. After a part of the aldehyde has been added, the mixture rapidly seta to a mass of crystals. Insert a cotton wool (or calcium chloride) tube into the mouth of the flask and allow the mixture to stand at room temperature for 60 hours with frequent shaking. Finally, warm the mixture on a water bath until the evolution of carbon dioxide ceases (about 8 hours) and then pour into an equal volume of water. Separate the oily layer and shake it with 150 ml. of 25 per cent hydrochloric acid to remove pyridine. Dissolve the product in benzene, wash with water, dry with anhydrous magnesium sulphate, and distil under reduced pressure. Collect the ap-nonenoic acid at 130-13272 mm. The yield is 62 g. 

It is convenient to divide the petrochemical industry into two general sectors (/) olefins and (2) aromatics and their respective derivatives. Olefins ate straight- or branched-chain unsaturated hydrocarbons, the most important being ethylene (qv), [74-85-1] propjiene (qv) [115-07-17, and butadiene (qv) [106-99-0J. Aromatics are cycHc unsaturated hydrocarbons, the most important being benzene (qv) [71-43-2] toluene (qv) [108-88-3] p- s.y en.e [106-42-3] and (9-xylene [95-47-5] (see Xylenes and ethylbenzene) There are two other large-volume petrochemicals that do not fall easily into either of these two categories ammonia (qv) [7664-41-7] and methanol (qv) [67-56-1]. These two products ate derived primarily from methane [74-82-8] (natural gas) (see Hydrocarbons, c -c ). 

Cyclic Hydrocarbons. The cyclic hydrocarbon intermediates are derived principally from petroleum and natural gas, though small amounts are derived from coal. Most cycHc intermediates are used in the manufacture of more advanced synthetic organic chemicals and finished products such as dyes, medicinal chemicals, elastomers, pesticides, and plastics and resins. Table 6 details the production and sales of cycHc intermediates in 1991. Benzene (qv) is the largest volume aromatic compound used in the chemical industry. It is extracted from catalytic reformates in refineries, and is produced by the dealkylation of toluene (qv) (see also BTX Processing). 

Although synthetic lubrication oil production amounts to only about 2% of the total market, volume has been increasing rapidly (67). Growth rates of the order of 20% per year for poly( a-olefin)s, 10% for polybutenes, and 8% for esters (28) reflect increasing automotive use and these increases would accelerate if synthetics were adopted for factory fill of engines by automotive manufacturers. The estimated production of poly( a-olefin)s for lubricants appears to be approximately 100,000 m /yr, esters 75,000, poly(alkylene glycol)s 42,000, polybutenes 38,000, phosphates 20,000, and dialkyl benzene 18,000 (28,67). The higher costs reflected in Table 18 (18,28) have restricted the volume of siUcones, chlorotrifluoroethylene, perfluoroalkylpolyethers, and polyphenyl ethers. 

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). 

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