Hydrogen commercial availability

Trimethylene dibromide (Section 111,35) is easily prepared from commercial trimethj lene glycol, whilst hexamethylene dibromide (1 O dibromohexane) is obtained by the red P - Br reaction upon the glycol 1 6-hexanediol is prepared by the reduction of diethyl adipate (sodium and alcohol lithium aluminium hydride or copper-chromium oxide and hydrogen under pressure). Penta-methylene dibromide (1 5-dibromopentane) is readily produced by the red P-Brj method from the commercially available 1 5 pentanediol or tetra-hydropyran (Section 111,37). Pentamethylene dibromide is also formed by the action of phosphorus pentabromide upon benzoyl piperidine (I) (from benzoyl chloride and piperidine) ... 

THPC—Amide—PoIy(vinyI bromide) Finish. A flame retardant based on THPC—amide plus poly(vinyl bromide) [25951-54-6] (143) has been reported suitable for use on 35/65, and perhaps on 50/50, polyester—cotton blends. It is appUed by the pad-dry-cure process, with curing at 150°C for about 3 min. A typical formulation contains 20% THPC, 3% disodium hydrogen phosphate, 6% urea, 3% trimethylolglycouril [496-46-8] and 12% poly(vinyl bromide) soUds. Approximately 20% add-on is required to impart flame retardancy to a 168 g/m 35/65 polyester—cotton fabric. Treated fabrics passed the FF 3-71 test. However, as far as can be determined, poly(vinyl bromide) is no longer commercially available. 

Hydrogen-storage alloys (18,19) are commercially available from several companies in the United States, Japan, and Europe. A commercial use has been developed in rechargeable nickel—metal hydride batteries which are superior to nickel—cadmium batteries by virtue of improved capacity and elimination of the toxic metal cadmium (see BATTERIES, SECONDARYCELLS-ALKALINe). Other uses are expected to develop in nonpolluting internal combustion engines and fuel cells (qv), heat pumps and refrigerators, and electric utility peak-load shaving. 

Much more important is the hydrogenation product of butynediol, 1,4-butanediol [110-63-4]. The intermediate 2-butene-l,4-diol is also commercially available but has found few uses. 1,4-Butanediol, however, is used widely in polyurethanes and is of increasing interest for the preparation of thermoplastic polyesters, especially the terephthalate. Butanediol is also used as the starting material for a further series of chemicals including tetrahydrofuran, y-butyrolactone, 2-pyrrohdinone, A/-methylpyrrohdinone, and A/-vinylpyrrohdinone (see Acetylene-DERIVED chemicals). The 1,4-butanediol market essentially represents the only growing demand for acetylene as a feedstock. This demand is reported (34) as growing from 54,000 metric tons of acetylene in 1989 to a projected level of 88,000 metric tons in 1994. 

Hydrogen use as a fuel in fuel cell appHcations is expected to increase. Fuel cells (qv) are devices which convert the chemical energy of a fuel and oxidant directiy into d-c electrical energy on a continuous basis, potentially approaching 100% efficiency. Large-scale (11 MW) phosphoric acid fuel cells have been commercially available since 1985 (276). Molten carbonate fuel cells (MCFCs) ate expected to be commercially available in the mid-1990s (277). 

Hydrogen peroxide [7722-84-17, mol wt 34.016, is a strong oxidising agent commercially available in aqueous solution over a wide range of... 

Molecular Addition. Oxyacid salts, metal peroxides, nitrogen compounds, and others from crystalline peroxyhydrates in the presence of hydrogen peroxide. When dissolved in water, the peroxyhydrates react as solutions of their components. The peroxyhydrates formed from sodium carbonate and urea are commercially available. Examples of peroxyhydrates can be found in the Hterature (29,30). 

The following commercially available dialkyl peroxides are produced according to equations 24—27 di-Z fZ-butyl peroxide from hydrogen peroxide and sulfated tert-huty alcohol or isobutylene dicumyl peroxide from a-cumyl hydroperoxide and cumyl alcohol, cumyl chloride, and/or a-methylstyrene m- and -di(2-/ f2 -butylperoxyisopropyl)ben2ene [2781-00-2] from tert-huty hydroperoxide [75-91-2] and m- and -di(2-hydroxyisopropyl)ben2ene ... 

Thiophenecarboxaldehyde [498-62-4] has been commercially available (35) via carbonylation of 2,5-dimethoxy-2,5-dihydrofuran, followed by treatment with hydrogen sulfide, which introduces the sulfur atom with loss of methanol, inducing aromaticity and producing 3-thiophenecarboxaldehyde directly. 

Peracids are also available as aqueous solutions that contain the peracid in equihbrium with hydrogen peroxide and the parent acid. Peracetic acid [79-21-0] is commercially available as a 40% solution in dilute acetic acid. The water and dilution of the peracid make these solutions easier to handle than their sohd counterparts, but they still require careful handling and protection from heat. 

A disadvantage of the hydrocarbon—sulfur process is the formation of one mole of hydrogen sulfide by-product for every two atoms of hydrogen in the hydrocarbon. Technology for efficient recovery of sulfur values in hydrogen sulfide became commercially available at about the same time that the methane—sulfur process was developed. With an efficient Claus sulfur recovery unit, the hydrocarbon—sulfur process is economically attractive. 

Analysis methods for hydrogen absorbed in the deposit have been described (65), and instmments are commercially available to detect hydrogen in metals. Several working tests have been devised that put plated specimens under strain and measure the time to failure. A method for cadmium-plated work has been described (66) as has a mechanical test method for evaluating treatments on AlSl 4340 Steel (67). Additional information on testing for hydrogen embrittlement is also available (68). 

Two other principles that have been made commercially available are (11 rhe reaction between pyrosulfuric acid (H2S2O7) and water (water vapor in air) to form sulfuric acid aerosol and (2) rhe reaction between ritaiJium tetrachloride (TiCl4) and water to form titanium dioxide (TiO,) and hydrogen chloride il Id), higure 12.5 shows two different hand-held, disposable smoke emitters. 

Isotope labeling by derivative formation with deuterated reagents is useful for the preparation of analogs such as dg-acetonides, da-acetates, da-methyl ethers, dg-methyl esters, etc. The required reagents are either commercially available or can be easily prepared. (The preparation of da-methyl iodide is described in section IX-F. Various procedures are reported in the literature for the preparation of dg-acetone, da-diazometh-ane57.i63.i73 and da-acetyl chloride. ) These reactions can be carried out under the usual conditions and they need no further discussion. A convenient procedure has been reported for the da-methylation of sterically hindered or hydrogen bonded phenolic hydroxyl functions by using da-methyl iodide and sodium hydroxide in dimethyl sulfoxide solution. This procedure should be equally applicable to the preparation of estradiol da-methyl ether derivatives. 

Anhydrous hydrogen fluonde Yield based on fluonne The compound is commercially available The compound has considerable vapor pressure... 

Anhydrous hydrogen fluoride "Thc compound is commercially available ... 

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