Dow Chemical process

In the Dow Chemical process calcium hydroxide is added to seawater, the precipitated hydroxide then being reacted with hydrogen chloride (the calcium precipitating as calcium sulfate due to the simultaneous addition of sulfuric acid) and the magnesium chloride solution is evaporated to dryness at ca. 200°C to produce a product with ca. 1.5 to 2 molecules of water. 

In the early days of the Dow Chemical process for producing magnesium metal, tonnes of Oyster shells were used as a source of pure calcium carbonate for the preparation of magnesia from seawater. 

Figure 2.42 Dow Chemicals process for recovering calcium chloride and other products from Michigan Brine in 2002 (after Pavlick, 1984).

Even ia 1960 a catalytic route was considered the answer to the pollution problem and the by-product sulfate, but nearly ten years elapsed before a process was developed that could be used commercially. Some of the eadier attempts iacluded hydrolysis of acrylonitrile on a sulfonic acid ion-exchange resia (69). Manganese dioxide showed some catalytic activity (70), and copper ions present ia two different valence states were described as catalyticaHy active (71), but copper metal by itself was not active. A variety of catalysts, such as Umshibara or I Jllmann copper and nickel, were used for the hydrolysis of aromatic nitriles, but aUphatic nitriles did not react usiag these catalysts (72). Beginning ia 1971 a series of patents were issued to The Dow Chemical Company (73) describiag the use of copper metal catalysis. Full-scale production was achieved the same year. A solution of acrylonitrile ia water was passed over a fixed bed of copper catalyst at 85°C, which produced a solution of acrylamide ia water with very high conversions and selectivities to acrylamide. 

The largest production of acrylamide is in Japan the United States and Europe also have large production faciUties. Some production is carried out in the Eastern Bloc countries, but details concerning quantities or processes are difficult to obtain. The principal producers in North America are The Dow Chemical Company, American Cyanamid Company, and Nalco Chemical Company (internal use) Dow sells only aqueous product and American Cyanamid sells both Hquid and sohd monomer. In Europe, Chemische Eabrik Stockhausen Cie, Ahied CoUoids, The Dow Chemical Company, and Cyanamid BV are producers Dow and American Cyanamid are the only suppHers to the merchant market, and crystalline monomer is available from American Cyanamid. Eor Japan, producers are Mitsubishi Chemical Industries, Mitsui Toatsu, and Nitto Chemical Industries Company (captive market). Crystals and solutions are available from Mitsui Toatsu and Mitsubishi, whereas only solution monomer is available from Nitto. 

Dow Eatex Foam Process, buUetin, The Dow Chemical Co., Midland, Mich. 

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). 

In the 1960s and 1970s ethyleneimine was produced by the dichioroethane—ammonia process by the Dow Chemical Co. 

Synthesis. The total aimual production of PO in the United States in 1993 was 1.77 biUion kg (57) and is expected to climb to 1.95 biUion kg with the addition of the Texaco plant (Table 1). There are two principal processes for producing PO, the chlorohydrin process favored by The Dow Chemical Company and indirect oxidation used by Arco and soon Texaco. Molybdenum catalysts are used commercially in indirect oxidation (58—61). Capacity data for PO production are shown in Table 1 (see Propylene oxide). 

Dow Chemical Company purchased the rights to MacaHum s patents (14), initiated a detailed study of the process and other improved syntheses of PPS in the 1950s and early 1960s, and pubUshed the results of their investigation (9,15,16). Clearly, alternative routes to PPS were desirable and the most promising of these involved the nucleophilic self-condensation of cuprous -bromothiophenoxide, carried out at 200—250°C in the soHd state or in the presence of pyridine (16) ... 

Union Carbide Chemicals and Plastics Company Inc. is the only producer of C-5 oxo derived alcohols (148,150) in the United States. About 75% of the 30,000 t of valeraldehyde and 2-methylbutyraldehyde produced by the oxo process was converted to the isomeric mixture of primary amyl alcohols in 1988 (150). The primary amyl alcohol mixture was available in tank car quantities for 1.02/kg in 1991. The Dow Chemical Company appears to have stopped commercial production of / fZ-amyl alcohol (151). 

The chlorohydrin process involves reaction of propylene and chlorine in the presence of water to produce the two isomers of propylene chlorohydrin. This is followed by dehydrochlorination using caustic or lime to propylene oxide and salt. The Dow Chemical Company is the only practitioner of the chlorohydrin process in North America. However, several companies practice the chlorohydrin process at more than 20 locations in Germany, Italy, Bra2il, Japan, Eastern Europe, and Asia. 

Aluminum Chloride-Based All lation. The eadier alkylation processes were variations of the Eriedel-Craft reaction on an aluminum chloride catalyst complex in a Hquid-phase reactor (27), including those developed by Dow Chemical, BASE, Monsanto, and Union Carbide in cooperation with Badger. The Union Carbide-Badger process was the one most widely used during the 1960s and 1970s, with 20 plants built worldwide. 

Dow Chemical was developiag a similar process based on an amine solution as of this writing (1997). 

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). 

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. 

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. 

Biphenyl has been produced commercially in the United States since 1926, mainly by The Dow Chemical Co., Monsanto Co., and Sun Oil Co. Currently, Dow, Monsanto, and Koch Chemical Co. are the principal biphenyl producers, with lesser amounts coming from Sybron Corp. and Chemol, Inc. With the exception of Monsanto, the above suppHers recover biphenyl from high boiler fractions that accompany the hydrodealkylation of toluene [108-88-3] to benzene (6). Hydrodealkylation of alkylbenzenes, usually toluene, C Hg, is an important source of benzene, C H, in the United States. Numerous hydrodealkylation (HDA) processes have been developed. Most have the common feature that toluene or other alkylbenzene plus hydrogen is passed under pressure through a tubular reactor at high temperature (34). Methane and benzene are the principal products formed. Dealkylation conditions are sufficiently severe to cause some dehydrocondensation of benzene and toluene molecules. 

The first large-scale commercial oxychlorination process for vinyl chloride was put on-stream in 1958 by The Dow Chemical Company. This plant, employing a fixed-tube reactor containing a catalyst of cupric chloride on an active carrier, produced 1,2-dichloroethane from ethylene. The high temperatures involved in the reaction were moderated by a suitable diluent. The average heat output from the reaction is 116 kJ/mol (50,000 Btu/lb mol). 

The principal U.S. producers of 1,1,1-trichloroethane include The Dow Chemical Company, PPG Industries Inc., and Vulcan Materials Co. Several European and Japanese companies also produce large amounts aimually. Over 70% of the production is based on the vinyl chloride-1,1-dichloroethane process, 20% on the 1,1-dichloroethylene process, and about 10% on the direct chlorination of ethane. 

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. 

The most important chemical reaction of chi orohydrin s is dehydrochloriaation to produce epoxides. In the case of propylene oxide. The Dow Chemical Company is the only manufacturer ia the United States that still uses the chlorohydrin technology. In 1990 the U.S. propylene oxide production capacity was hsted as 1.43 x 10 t/yr, shared almost equally by Dow and Arco Chemical Co., which uses a process based on hydroperoxide iatermediates (69,70). More recentiy, Dow Europe SA, aimounced a decision to expand its propylene oxide capacity by 160,000 metric tons per year at the Stade, Germany site. This represents about a 40% iacrease over the current capacity (71). 

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