Hydrogenation, with Ni catalyst

H-acid, l-hydroxy-3,6,8-ttisulfonic acid, which is one of the most important letter acids, is prepared as naphthalene is sulfonated with sulfuric acid to ttisulfonic acid. The product is then nitrated and neutralized with lime to produce the calcium salt of l-nitronaphthalene-3,6,8-ttisulfonic acid, which is then reduced to T-acid (Koch acid) with Fe and HCl modem processes use continuous catalytical hydrogenation with Ni catalyst. Hydrogenation has been performed in aqueous medium in the presence of Raney nickel or Raney Ni—Fe catalyst with a low catalyst consumption and better yield (51). Fusion of the T-acid with sodium hydroxide and neutralization with sulfuric acid yields H-acid. Azo dyes such as Direct Blue 15 [2429-74-5] (17) and Acid... 

The l,4-dichloro-2-butene can also be separated and hydroly2ed with aqueous NaOH to form 1,4-butenediol, which is hydrogenated with Ni catalyst to produce 1,4-butanediol. In 1971 this process was commerciali2ed in Japan (55). The plant is now shut down because of unfavorable economics. 

These reactors for hquids and liquids plus gases employ small particles in the range of 0.05 to 1.0 mm (0.0020 to 0.039 in), the minimum size hmited by filterability. Small diameters are used to provide as large an interface as possible since the internal surface of porous pellets is poorly accessible to the hquid phase. Solids concentrations up to 10 percent by volume can be handled. In hydrogenation of oils with Ni catalyst, however, the sohds content is about 0.5 percent, and in the manufacture of hydroxylamine phosphate with Pd-C it is 0.05 percent. Fischer-Tropsch slurry reac tors have been tested with concentrations of 10 to 950 g catalyst/L (0.624 to 59.3 IbiTi/fF) (Satterfield and Huff, Chem. Eng. Sci., 35, 195 [1980]). 

Add with stirring, in small portions over Vi hour, 40 g 50% Raney-Ni to 600 ml 10% NaOH in a 1 L three-neck flask and continue stirring one hour. Let the Ni settle and decant the solution. Wash residue with 5X200 ml water, 5X50 ml ethanol, always keeping the Ni covered with liquid. Store under ethanol in refrigerator. Hydrogenation with this catalyst can be carried out in a low pressure Parr bottle (e.g., 30-80 ml ethanol, 5-10 g Ni suspension, 1-2 ml 20% NaOH, 40° - 50° and 40-60 PSI H ). 

On the other hand, the work by Yan et al. and Jin et al. using silicon wafers and Ni as catalysts has suggested that bulk silicon would diffuse through the nanoparticles to produce SiNW. In this case, solid silicon in the wafer reacts with Ni catalysts to directly make SiNW. If this is true, it falls into the category of root growth. However, as we will illustrate below, the use of hydrogen in the presence of metal catalysts may activate a new reaction pathway that converts Si in the substrate into silane. As a result, the suggested solid-liquid-solid model may actually be the VLS model at work. 

D-Glucitol (Sorbitol or Hexanhexol), HOCH2(CHaOH)4CH2OH raw 182.17, ndls (with lA or 1 w), tnp about ll0°(dry), -100° or less (with w), very hygr when dry sol in w hot ale. Found in various fruits prepd by sodium amalgam reduction of d-sorbose or by pressure hydrogenation of dextrose with Ni catalyst. Used far prepn of ascorbic acid (Vitamin C), for synthesis of resins, surface-active agents, varnishes, syrups, cosmetic creams aod for explosive Sorbitol Hexanitrate... 

Industrial processes were developed for the selective partial hydrogenation of 4-vinylcyclohexene with Ni catalysts exhibiting minimized isomerization activity in the presence of additives298,299. For example, supported nickel arsenides prepared by reducing nickel arsenate with NaBFLt display high selectivity in the formation of 4-ethylcyclohexene (96% selectivity at 96% conversion on Ni-As-Al2C>3, 398 K, 25 atm H2, acetone additive). 

Fig. 22. Configurational entropy for adsorption of hydrogen on Ni catalyst 8505 (I) experimental data, (II) theoretical values for homogeneous surface with completely random adsorption.

From ethyl l-methylpiperidine-3-carboxylate (which was prepared by hydrogenation of ethyl nicotinate with Ni-catalyst and then by methylation by action dimethyl sulfate) and 2-thienyl magnesium bromide was synthesized l,l-di(thiophen-2-yl)-2-(3 -N-methylpiperidine), 3-(di-2-thienylmethylene)-l-methylpiperidine was obtained by dehydration of l,l-di(thiophen-2-yl)-2-(3 -N-methylpiperidine) by action of base. 

Therefore, one reaction is sufficient to determine the bond energy of hydrogen with a catalyst if the activation energy is known from experiment e can be taken from literature data. Let us substitute H instead of A, B, C, D, and Ni instead of K into Eq. (II.9). Then from the already known ei = 5.9 [see Fayans (401)] and Qhh = 104.2 kcal we find from Eq. (II.9) that... 

Multicomponent metallic hydrogenation catalysts, based on intermetallic compounds (IMC) of rare-earth elements with nickel, copper, cobalt, and other bimetallic systems. Most studies were devoted to two structural systems LnMs and LnMs, where Ln = La, Sm, Gd, Ce, Pr, and Nd and M = Ni (see Klabunovskii, Konenko s group 183,251,252 Compaiison of LnNis catalysts with Ni catalysts supported on oxides of Ln, show higher activities of the IMC s and their hydrides in hydrogenation of propene (100°C, 1 bar), where LaNis proved to be the most active catalyst... 

Nitta, Y., and Imanaka, T. (1988) Effect of pore diffusion in liquid-phase enantioselective hydrogenation with Ni-silica catalysts. Bull Chem. Soc. Jpn., 61, 295 - 297. 

Formation of anhydride succeeds with Ni catalysts even at lower temperatures (230 to 250 °C) than the synthesis of propionic acid from ethylene. Thiolcarboxylic acid esters are obtained analogously by addition of thiols instead of carboxylic acids (2). Olefins, carbon monoxide and amines react to give saturated carboxylic acid amides (3) and acid chlorides are formed from hydrogen chloride and carbon monoxide in the presence of noble metal catalysts of the 8th group of the periodic table of the elements (4). 

The property of f. to be local irritants of eyes and skin is reduced by ethoxylation. Manufacturing from RR is predominantly done via the fatty nitriles, which are made from fatty acids by reaction with ammonia. The nitriles are reduced by - hydrogenation (batch or continuous) into amines. The reaction conditions determine whether primary, secondary or tertiary amines result. Saturated f are formed when nitriles are hydrogenated at 80-140 °C and 1-4 MPa/lO O bar over Ni catalyst. Unsaturated f can be obtained with Raney Co or Cu-chromite as catalyst. Ammonia has to be present to suppress the formation of secondary amines. Saturated and unsaturated secondary amines are gained in yields of more than 90% if ammonia is vented from the reactor, the reaction temperature is 160-210 °C, and pressure is maintained at 5-10 MPa/50-100 bar. Trialkylamines are produced via the imine R-CH=NH and Schiff base R-CH=N-CH3 with Ni catalyst at 230 °C and 0.7 MPa/7 bar hydrogen pressure. Important amine types, which are the base for making dimethyl dialkyl ammonium compounds, are made by the following reaction ... 

Diamine. 2,2-Dimethyl-l,3-propanediamine [7328-91-8] (5) has been prepared by amination of neopentyl glycol by treating the glycol with ammonia and hydrogen at 150—250°C at 10—31 MPa (1500—4500 psig) over a Ni catalyst. The diamine is useflil for preparation of crystalline polyureas by reaction with diisocyanates (36). 

Most current industrial vitamin C production is based on the efficient second synthesis developed by Reichstein and Grbssner in 1934 (15). Various attempts to develop a superior, more economical L-ascorbic acid process have been reported since 1934. These approaches, which have met with htde success, ate summarized in Crawford s comprehensive review (46). Currently, all chemical syntheses of vitamin C involve modifications of the Reichstein and Grbssner approach (Fig. 5). In the first step, D-glucose (4) is catalytically (Ni-catalyst) hydrogenated to D-sorbitol (20). Oxidation to L-sotbose (21) occurs microhiologicaRy with The isolated L-sotbose is reacted with acetone and sulfuric acid to yield 2,3 4,6 diacetone-L-sorbose,... 

The hydrogenation of benzene produces cyclohexane. Many catalyst systems, such as Ni/alumina and Ni/Pd, are used for the reaction. General reaction conditions are 160-220°C and 25-30 atmospheres. Higher temperatures and pressures may also be used with sulfided catalysts ... 

Mn02) [56], The XANES spectra at the Ni K-edge indicates that, unlike the ABS alloys, there is very little interaction between hydrogen and Ni but rather strong interactions with Ti, V, and Zr. The hydrogen is presumably located in tetrahedra that contain large fractions of these three elements, whereas the Ni-rich sites are probably empty. Thus the function of Ni in AB2 alloys may be primarily to serve as a catalyst for the electrochemical hydriding reactions. 

Fig. 15. Kinetics of the ethylene hydrogenation on Ni and 0-Ni-hydride film catalysts m denotes mass of films, which as known is connected with the thickness and crystallite sizes of the films involved. Blank points—rate of reaction proceeding on Ni film catalysts black points—rate of reaction proceeding on nickel previously exposed to the atomic hydrogen action, i.e. transformed to some extent into /3-Ni-hydride.

Catalytic hydrogenation seldom breaks unactivated C—C bonds (i.e., R—R + H2 RH + R H), but methyl and ethyl groups have been cleaved from substituted adamantanes by hydrogenation with a Ni-Al203 catalyst at about 250°C. Certain C—C bonds have been cleaved by alkali metals. ... 

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