Liquid-phase process

The roasting process, or variations of it, are most common. Liquid-phase processes are ia operation, however, both ia the United States and the former USSR. The former USSR is the only place where KMnO was produced by anodic oxidation of ferromanganese. Table 17 summarizes the various KMnO manufactuting faciUties worldwide as of this writing. 

Isopropyl alcohol can be partially oxidized by a noncatalytic, liquid-phase process at low temperatures and pressure to produce hydrogen peroxide [7722-84-1] and acetone (24—26). 

In some liquid-phase processes, catalyst components are slowly leached from the catalyst bed and eventually the catalyst must be replaced. The feasibility of this type of process involves economics, ie, the costs of catalyst maintenance and keeping a unit out of service for catalyst replacement, and product quality and safety, ie, the effects of having catalyst components in the product and their ease of removal. 

Arsenic-Catalyzed Liquid-Phase Process. An arsenic catalyst Liquid-phase process for olefin oxides has been patented by Union Carbide... 

Gas- or vapor-phase processes Liquid-phase processes ... 

Liquid phase processes, such as hydrogenation, halogenation, oxidation, nitration, kylation, and so on... 

Membrane Pervaporation Since 1987, membrane pei vapora-tion has become widely accepted in the CPI as an effective means of separation and recovery of liquid-phase process streams. It is most commonly used to dehydrate hquid hydrocarbons to yield a high-purity ethanol, isopropanol, and ethylene glycol product. The method basically consists of a selec tively-permeable membrane layer separating a liquid feed stream and a gas phase permeate stream as shown in Fig. 25-19. The permeation rate and selectivity is governed bv the physicochemical composition of the membrane. Pei vaporation differs From reverse osmosis systems in that the permeate rate is not a function of osmotic pressure, since the permeate is maintained at saturation pressure (Ref. 24). 

Barona, N. and H. V. Prengle, Design Reactors This Way for Liquid-Phase Processes, Hydrocarbon Processing, V. 52, No. 3, 1973, p. 63. 

Zinc chloride is also a catalyst for a liquid-phase process using concentrated hydrochloric acid at 100-150°C. Hydrochloric acid may be generated in situ by reacting sodium chloride with sulfuric acid. As mentioned earlier, methyl chloride may also be produced directly from methane with other chloromethanes. However, methyl chloride from methanol may be further chlorinated to produce dichloromethane, chloroform, and carbon tetrachloride. 

The carbonylation of methanol is currently one of the major routes for acetic acid production. The basic liquid-phase process developed by BASF uses a cobalt catalyst at 250°C and a high pressure of about 70... 

The process is similar to the catalytic liquid-phase oxidation of ethylene to acetaldehyde. The difference hetween the two processes is the presence of acetic acid. In practice, acetaldehyde is a major coproduct. The mole ratio of acetaldehyde to vinyl acetate can he varied from 0.3 1 to 2.5 1. The liquid-phase process is not used extensively due to corrosion problems and the formation of a fairly wide variety of by-products. 

In the liquid-phase process, high pressures in the range of 80-100 atmospheres are used. A sulfonated polystyrene cation exchange resin is the catalyst commonly used at about 150°C. An isopropanol yield of 93.5% can be realized at 75% propylene conversion. The only important byproduct is diisopropyl ether (about 5%). Figure 8-4 is a flow diagram of the propylene hydration process. ... 

The metathetic reaction occurs in the gas phase at relatively high temperatures (150°-350°C) with molybdenum or tungsten supported catalysts or at low temperature (=50°C) with rhenium-based catalyst in either liquid or gas-phase. The liquid-phase process gives a better conversion. Equilibrium conversion in the range of 55-65% could be realized, depending on the reaction temperature. ... 

The process which was developed hy DOW involves cyclodimerization of hutadiene over a proprietary copper-loaded zeolite catalyst at moderate temperature and pressure (100°C and 250 psig). To increase the yield, the cyclodimerization step takes place in a liquid phase process over the catalyst. Selectivity for vinylcyclohexene (VCH) was over 99%. In the second step VCH is oxidized with oxygen over a proprietary oxide catalyst in presence of steam. Conversion over 90% and selectivity to styrene of 92% could he achieved. ... 

Either a liquid or a gas-phase process is used for the alkylation reaction. In the liquid-phase process, low temperatures and pressures (approximately 50°C and 5 atmospheres ) are used with sulfuric acid as a catalyst. 

Alkylation of benzene with linear monoolefms is industrially preferred. The Detal process (Figure 10-9) combines the dehydrogenation of n-paraffins and the alkylation of benzene. Monoolefms from the dehydrogenation section are introduced to a fixed-bed alkylation reactor over a heterogeneous solid catalyst. Older processes use HF catalysts in a liquid phase process at a temperature range of 40-70°C. The general alkylation reaction of benzene using alpha olefins could be represented as ... 

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... 

Cyclohexane is oxidized in a liquid-phase process to a mixture of cyclohexanone and cyclohexanol (KA oil). The reaction conditions are 95-120°C at approximately 10 atmospheres in the presence of a cohalt acetate and orthohoric acid catalyst system. About 95% yield can be obtained ... 

The reaction occurs in a liquid-phase process at approximately 400°C using ZnO or CdO catalysts. Terephthalic acid is obtained from an acid treatment the potassium salt is recycled. ° ... 

Deparaffmization processes working with weakly adsorbed media in the desorption step can be performed as well as gas or liquid phase processes. The following examples of industrial importance explain the procedure in practical operation. 

Liquid phase process using a suspended catalyst, or... 

The paraffin wax is oxidized by air in a liquid phase process at 110-130°C. Catalysts for this radical reaction are cobalt or manganese salts [54]. The quality of the obtained mixture of homologous carboxylic acids is impaired by numerous byproducts such as aldehydes, ketones, lactones, esters, dicarboxylic acids, and other compounds. These are formed despite a partial conversion of the paraffin and necessitate an expensive workup of the reaction product [50,55]. 

Chemical vapor deposition competes directly with other coating processes which, in many cases, are more suitable for the application under consideration. These competing processes comprise the physical vapor deposition (PVD) processes of evaporation, sputtering, and ion plating, as well as the molten-material process of thermal spray and the liquid-phase process of solgel. A short description of each process follows. For greater detail, the listed references should be consulted. 

The process of direct synthesis of DME includes reactions of methanol synthesis and methanol dehydration, which are catalyzed by two different catalysts. Although the technology for the production of methanol is generally considered mature, most of thran are gas phase process, and the performances of these catalysts are restricted remarkably in liquid phase process. Development of high performance bifunctional catalyst system is very... 

The chemistry of vinyl acetate synthesis from the gas-phase oxidative coupling of acetic acid with ethylene has been shown to be facilitated by many co-catalysts. Since the inception of the ethylene-based homogeneous liquid-phase process by Moiseev et al. (1960), the active c ytic species in both the liquid and gas-phase process has always been seen to be some form of palladium acetate [Nakamura et al, 1971 Augustine and Blitz, 1993]. Many co-catalysts which help to enhance the productivity or selectivity of the catalyst have appeared in the literature over the years. The most notable promoters being gold (Au) [Sennewald et al., 1971 Bissot, 1977], cadmium acetate (Cd(OAc)j) [Hoechst, 1967], and potassium acetate (KOAc) [Sennewald et al., 1971 Bissot, 1977]. 

Current state-of-the-art technology for the production of MIBK involves one-step liquid phase processes in trickle bed reactors at 100-160°C and 1 to 10 MPa utilizing various multifunctional catalysts including Pd, Pt, Ni or Cu supported on, metal oxides, cation exchange resins, modified ZSM5 and other zeolites with lull energy integration (2,3,4). However, the MIBK... 

Nonisothermal liquid-phase processes may be driven by changes in feed temperature or heat addition or withdrawal through a column wall. For these, heats of adsorption and pressure effects are generally of less concern. For this case a suitable energy balance is... 

EBMax A continuous, liquid-phase process for making ethylbenzene from ethylene and benzene, using a zeolite catalyst. Developed by Raytheon Engineers and Constructors and Mobil Oil Corporation and first installed at Chiba Styrene Monomer in Japan in 1995. Generally similar to the Mobil/Badger process, but the improved catalyst permits the reactor size to be reduced by two thirds. 

Ethylbenzene Also called UOP Ethylbenzene. A liquid-phase process for making ethylbenzene by reacting ethylene with benzene, catalyzed by a zeolite. The process is usually coupled with one for converting ethylbenzene to styrene. Developed by Unocal Corporation and now licensed by UOP and ABB Lummus Crest. 

Phillips (1) A process for polymerizing ethylene and other linear olefins and di-olefins to make linear polymers. This is a liquid-phase process, operated in a hydrocarbon solvent at an intermediate pressure, using a heterogeneous oxide catalyst such as chromia on silica/ alumina. Developed in the 1950s by the Phillips Petroleum Company, Bartlesville, OK, and first commercialized at its plant in Pasadena, TX. In 1991, 77 reaction fines were either operating or under construction worldwide, accounting for 34 percent of worldwide capacity for linear polyethylene. 

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