Production using small amounts

Furfural Production Using Small Amounts of Strong Catalysts... 

Figure 5. Flow diagram of furfural production using small amounts of strong catalysts.

Acryhc and modacryhc fibers are sold mainly as staple and tow products with small amounts of continuous filament fiber sold in Europe and Japan. Staple lengths may vary from 25 to 150 mm, depending on the end use. Eiber deniers may vary from 1.3 to 17 dtex (1.2 to 15 den) 3.2 dtex (3.0 den) is the standard form. The appearance of acryhcs under microscopical examination may differ from that of modacryhcs in two respects. Eirst, the cross sections (Eig. 1) of acryhcs are generally round, bean-shaped, or dogbone-shaped. The modacryhcs, on the other hand, vary from irregularly round to ribbon-like. The modacryhcs may also contain pigment-like particles of antimony oxide to enhance their flame-retardant properties. 

Production of maleic anhydride by oxidation of / -butane represents one of butane s largest markets. Butane and LPG are also used as feedstocks for ethylene production by thermal cracking. A relatively new use for butane of growing importance is isomerization to isobutane, followed by dehydrogenation to isobutylene for use in MTBE synthesis. Smaller chemical uses include production of acetic acid and by-products. Methyl ethyl ketone (MEK) is the principal by-product, though small amounts of formic, propionic, and butyric acid are also produced. / -Butane is also used as a solvent in Hquid—Hquid extraction of heavy oils in a deasphalting process. 

Aluminum hydroxides are technically the most widely used members of the alurnina chemicals family. The most important source of aluminum hydroxides is the bauxite refining plant for alurnina production. A small amount of somewhat purer aluminum hydroxide is produced by the Sinter process. 

Minor Uses. Small amounts of benzene find use in production of benzene-sulfonic acid. y -Benzenedisulfonic acid is used to produce resorcinol [108-46-3] (1,3-dihydroxybenzene). Benzene is thermally dimerized to yield biphenyl [92-52-4] Benzene can also be converted... 

Dichloroethane is produced by the vapor- (28) or Hquid-phase chlorination of ethylene. Most Hquid-phase processes use small amounts of ferric chloride as the catalyst. Other catalysts claimed in the patent Hterature include aluminum chloride, antimony pentachloride, and cupric chloride and an ammonium, alkaU, or alkaline-earth tetrachloroferrate (29). The chlorination is carried out at 40—50°C with 5% air or other free-radical inhibitors (30) added to prevent substitution chlorination of the product. Selectivities under these conditions are nearly stoichiometric to the desired product. The exothermic heat of reaction vapori2es the 1,2-dichloroethane product, which is purified by distillation. 

This combination of monomers is unique in that the two are very different chemically, and in thek character in a polymer. Polybutadiene homopolymer has a low glass-transition temperature, remaining mbbery as low as —85° C, and is a very nonpolar substance with Htde resistance to hydrocarbon fluids such as oil or gasoline. Polyacrylonitrile, on the other hand, has a glass temperature of about 110°C, and is very polar and resistant to hydrocarbon fluids (see Acrylonitrile polymers). As a result, copolymerization of the two monomers at different ratios provides a wide choice of combinations of properties. In addition to providing the mbbery nature to the copolymer, butadiene also provides residual unsaturation, both in the main chain in the case of 1,4, or in a side chain in the case of 1,2 polymerization. This residual unsaturation is useful as a cure site for vulcanization by sulfur or by peroxides, but is also a weak point for chemical attack, such as oxidation, especially at elevated temperatures. As a result, all commercial NBR products contain small amounts ( 0.5-2.5%) of antioxidant to protect the polymer during its manufacture, storage, and use. 

Use of some pyridinium oxides in this reaction was also described and the formed azaphenoxathiin /V-oxides can be easily converted to their mother heterocycles (80JHC989, 87JHC211). When 3-chloro-4-nitropyridine 1-oxide (271) was used, small amounts of products of Smiles rearrangement were... 

Higher eukaryotic expression systems are usually used for production of small amounts of protein for example, for analytical purposes or if a native conformation of complex enzymes has to be obtained. They can further be used to modify enzymes which were produced by lower... 

Two methods to secure very small samples of francium for examination use the decay processes of other radioactive elements. One is to bombard thorium with protons. The second is to start with radium in an accelerator, where, through a series of decay processes, the radium is converted to actinium, which in turn rapidly decays into thorium, and finally, thorium decays naturally into francium. Following is a schematic of the decay process used for the production of small amounts of Fr-223 which, in turn, after several more decay processes ends up as stable lead (Pb) ... 

We used small amounts of reactants and products to assure that we reached equilibrium, and we now cancel the subscripts in each term to arrive at... 

Citric acid, which prior to 1922 was made entirely from citrus fruits and mainly in Italy, is now produced almost exclusively by the fermentation of sucrose by means of a mold, Aspergillus niger. At first pure sucrose was used for this process but more recently molasses has been used instead. Practically the whole of the world production of citric acid is used as such in medicinal preparations, in making soft drinks and in certain foods. The textile industries use small amounts, and it is also... 

F. Haber Reports the production of small amounts of NH3. from N2 + 3H2 using an iron catalyst 1905... 

Minor Uses. Small amounts of benzene find use in production of benzene-sulfonic acid. ///- B enz ene dis ulfonic acid is used to produce resorcinol [108-46-3], C6H602, (1,3-dihydroxybenzene). Benzene is thermally dimerized to yield biphenyl [92-52-4], C12H10. Benzene can also be converted into />-diisopropylbenzene [100-18-5], C12H18, which is oxidized to hydroquinone (1,4-dihydroxybenzene), a useful antioxidant. Because of its well-recognized toxicity, litde benzene is employed for solvent purposes, and then only when no suitable substitutes are available. 

The most common wheat species used in food production is ordinary wheat, also called bread wheat (Triticum aestivum). It is an allohexaploid (AABBDD), in which the genomes were obtained by spontaneous hybridization of T. turgidum (AABB) and Aegilops tauschii (DD) about 10,000 years ago (Vasil, 2007). Other grown wheat species are tetraploidal durum wheat T. durum, used in pasta production and small amounts of hexaploidal spelt T. spelta and tetraploidal T. polonicum (Curtis et al. 2002). 

Gravitis et al. (2001) also reported a novel technology consisting of a two-step selective catalysis of wood and other pentosan-containing raw materials for the production of various chemicals (i.e. furfural, levoglucosan, ethanol) by using small amounts of strong catalysts. Furfural could be used for the production of dyes, plastics and fumaric acid. 

One equivalent of NaOEt in EtOH deprotonates diethyl malonate completely to give the sodium enolate A (Figure 13.36). This enolate is monoalkylated upon addition of an alkylating reagent such as BuBr, and a substituted malonic ester C is formed. During the alkylation reaction, the substituted malonic ester C reacts to a certain extent with some of the enolate A, resulting in the butylated enolate B and unsubstituted neutral malonic ester. It is for this reason that the reaction mixture contains two nucleophiles—the original enolate A and the butylated enolate B. The alkylation of A with butyl bromide is much faster than that of B, since A is less sterically hindered than B. The main product is therefore the product of monoalkylation. Distillation can be used to separate the main product from small amounts of the product of dialkylation. 

As shown in Fig. 18.23, dry liquid feed containing olefins and isobutane is charged to a combined reactor-settler. In this example, the reactor uses the principle of a differential gravity head to circulate through a cooler before contacting a highly dispersed hydrocarbon feed in the reactor pipe. The hydrocarbon phase, generated in the settler, is sent to a fractionator, which separates LPG-quality propane, isobutane recycle, n-butane, and alkylate products. A small amount of dissolved catalyst is also removed from the propane product by a small stripper tower. 

Ozone produced by the UV-irradiation of air has a concentration in the range of a few thousand parts per million. This method is used for the production of small amounts of ozone. 

The buildup of methylmalonyl-CoA in the cell may lead to reversal of the reaction of propionyl-CoA carboxylase and, as a consequence, an increase in the levels of propionyl-CoA. Increased levels of propionyl-CoA can lead to its use, in place of acetyl-CoA, by fatty acid synthase. Use of the 3-carbon propionyl group, rather than the 2-carbon acetyl group, by this enzyme can result in the production of small amounts of odd-chain fatty acids. These fatty acids contain an odd number of carbons, that is, 15,17, or 19 carbons. The addition of large amounts of propionic add to the diet during B 2 deficiency can be used to artifidally enhance the production of odd-chain fatty adds. 

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