Chlorine manufacture from hydrogen

Vinyl fluoride (fluoroethene), is manufactured from the cataly2ed addition of hydrogen fluoride to acetylene. It is used to prepare poly(vinyl fluoride) which has found use in highly weather-resistant films (Tedlar film, Du Pont). Poly(vinyhdene fluoride) also is used in weather-resistant coatings (see Eluorine compounds, organic). The monomer can be prepared from acetylene, hydrogen fluoride, and chlorine but other nonacetylenic routes are available. 

At present about 77% of the industrial hydrogen produced is from petrochemicals, 18% from coal, 4% by electrolysis of aqueous solutions and at most 1% from other sources. Thus, hydrogen is produced as a byproduct of the brine electrolysis process for the manufacture of chlorine and sodium hydroxide (p. 798). The ratio of H2 Cl2 NaOH is, of course, fixed by stoichiometry and this is an economic determinant since bulk transport of the byproduct hydrogen is expensive. To illustrate the scde of the problem the total world chlorine production capacity is about 38 million tonnes per year which corresponds to 105000 toimes of hydrogen (1.3 x I0 m ). Plants designed specifically for the electrolytic manufacture of hydrogen as the main product, use steel cells and aqueous potassium hydroxide as electrolyte. The cells may be operated at atmospheric pressure (Knowles cells) or at 30 atm (Lonza cells). 

BPR [By-Product Recycle] A process for recycling the chlorine-containing by products from the manufacture of vinyl chloride, 1,2-dichloroethane, and other chlorinated hydrocarbons. Combustion with oxygen converts 90 percent of the chlorine to anhydrous hydrogen chloride, and 10 percent to aqueous hydrochloric acid. Developed by BASF and licensed by European Vinyl Corp. 

Chlorine (Cl), 6 130-211 9 280. See also Inorganic chlorine XeCl laser addition to fullerene, 12 240-241 analytical methods, 6 202 bleaching agent, 4 50 capacities of facilities, 6 193-198t catalyst poison, 5 257t chemical properties, 6 133-138 diffusion coefficient for dilute gas in water at 20° C, l 67t diffusion coefficient in air at 0° C, l 70t for disinfection, 8 605 economic aspects, 6 188-202 electrolytic preparation/production of, 12 759 16 40 end uses, 6 134-135 in fused quartz manufacture, 22 413 generating from hydrogen chloride, 13 833... 

Most CFCs are manufactured by combining hydrogen fluoride and either carbon tetrachloride or chloroform. The hydrogen fluoride comes from fluorspar, CaF2, reacting with sulfuric acid. The chlorinated methanes are manufactured from methane. Important reactions in the manufacture of CFC-11 and -12 and HCFC-22 are given in Fig. 12.2. 

Most chlorine is manufactured from the electrolysis of saltwater, as shown below. Notably, this reaction also produces two other valuable chemicals, sodium hydroxide, NaOH, and hydrogen, H2. 

Non-Electrolytic Processes for the Manufacture of Chlorine from Hydrogen Chloride... 

The non-electrolytic processes for the manufacture of chlorine from hydrogen chloride (Deacon, air oxidation of hydrogen chloride Weldon, manganese dioxide oxidation of hydrogen chloride) which marked the beginning of industrial chlorine chemistry, are currently of only minor importance. 

Conventional hydrochloric acid electrolyzers consist of 30-36 individual cells connected in series (bipolar arrangement). The cells are formed from vertical electrode plates manufactured from graphite, between which there are diaphragms (for instance made from PVC fabric, distance to the plates ca. 6 mm). The feed with hydrochloric acid (22 wt%, identical for anode and cathode compartment) and the removal of the gases produced take place according to the filter press principle (see Chapter 2). Chlorine leaves the cell with the anolyte, hydrogen with the catholyte. 

When chlorine is reacted with a fuel in a burner, as in the manufacture of HC1 from Hydrogen and chlorine or in the manufacture of chlorinated solvents from hydrocarbons and chlorine, most incidents occur when the burner is set on-stream, either by lighting the burner with a pilot flame or by preheating the gas and the burner. Of course the gas mixture is in the flammable range and explosions occur due to maloperation. 

Chlorinated polyether, A thermoplastic manufactured from pentaerythrite — C(CH20H)4 — and hydrogen chloride. High chemical resistance and thermal stability (up to 120 °C). Applications pipes, fittings, pumps for the chemical industry. Trade name Penton (USA). 

A survey of the modulus as a function of exfoliation efficiency of Cloisite 30B in polyethylene with a varying degree of chlorine content is provided by Kim and White [44]. Polyethylene (2045 LLDPE produced by Dow) was the control. The wt. % chlorine content increased from chlorinated polyethylene (Tyrin random replacement of hydrogen with chlorine on the polymer backbone 36% chlorine, manufactured by DuPont Dow Elastomers), polyvinyl chloride (334 EG 56.7% chlorine, manufactured by OxyVinyl), chlorinated polyvinyl chloride (TempRite, 63.5% chlorine, manufactured by Noveon), to polyvinylidene chloride (Saran, greater than 71.5% chlorine, manufactured by Dow Chemical). The composites were prepared with a Brabender internal mixer at 180°C and 100 r/min. The composites were prepared with 3, 5, and 10 wt.% Cloisite 30B content. The samples for mechanical testing were prepared by compression molding. The composites were characterized by WAXS and TEM. 

This review is a survey of the applications and properties of supported liquid phase catalysts (SLP). By a supported liquid phase catalyst is meant the distribution of a catalytically active liquid on an inert porous support and the behaviour of such systems raises many interesting questions on catalyst chemistry, mass transfer in catalysts and reactor design. It is noteworthy thou that such systems have been employed in the chemical industry for many decades - indeed for over a century in the Deacon process for obtaining chlorine from hydrogen chloride - and of almost equally respectable antiquity are the vanadium based catalyst systems used for sulfuric acid manufacture but the recognition of SLP catalysts as possessing features of their own is much more recent. 

Each isomer has its individual set of physical and chemical properties however, these properties are similar (Table 6). The fundamental chemical reactions for pentanes are sulfonation to form sulfonic acids, chlorination to form chlorides, nitration to form nitropentanes, oxidation to form various compounds, and cracking to form free radicals. Many of these reactions are used to produce intermediates for the manufacture of industrial chemicals. Generally the reactivity increases from a primary to a secondary to a tertiary hydrogen (37). Other properties available but not Hsted are given in equations for heat capacity and viscosity (34), and saturated Hquid density (36). 

Hydrogen chloride is produced by the direct reaction of hydrogen and chlorine, by reaction of metal chlorides and acids, and as a by-product from many chemical manufacturing processes such as chlorinated hydrocarbons. 

Hydrogen Chloride as By-Product from Chemical Processes. Over 90% of the hydrogen chloride produced in the United States is a by-product from various chemical processes. The cmde HCl generated in these processes is generally contaminated with impurities such as unreacted chlorine, organics, chlorinated organics, and entrained catalyst particles. A wide variety of techniques are employed to treat these HCl streams to obtain either anhydrous HCl or hydrochloric acid. Some of the processes in which HCl is produced as a by-product are the manufacture of chlorofluorohydrocarbons, manufacture of aUphatic and aromatic hydrocarbons, production of high surface area siUca (qv), and the manufacture of phosphoric acid [7664-38-2] and esters of phosphoric acid (see Phosphoric acid and phosphates). 

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