Nickel condenser

In (1) the electrolytic process, a nickel of 99.9% purity is produced, along with slimes which may contain gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and cobalt, which are subject to further refining and recovery. In (2) the Mond process, the nickel oxide is combined with carbon monoxide to form nickel carbonyl gas, Ni(CO)4. The impurities, including cobalt, are left as a solid residue. Upon fuitlier heating of the gas to about 180°C, the nickel carbonyl is decomposed, the freed nickel condensing on nickel shot and the carbon monoxide recycled. The Mond process also makes a nickel of 99.9% purity. 

Kirk, W. W., and Tuthill, A. H., Copper-Nickel Condenser and Heat Exchanger Systems, http //marine.copper.org/3-toc.html, 1998. (GENERIC) Ref Type Electronic Citation... 

The first HCN addition (eq. 3) occurs at practical rates above 70°C under sufficient pressure to keep butadiene condensed in solution and produces the 1,4- and 1,2-addition products (3-pentenenitrile [4635-87-4] 3PN, and 2-meth5i-3-butenenitrile [16529-56-9] 2M3BN) in a 2 to 1 ratio. Fortunately, thermodynamics favors 3PN (about 20 1) and 2M3BN may be isomerized to 3PN (eq. 4) in the presence of a nickel catalyst. 

Reactions with Ammonia and Amines. Acetaldehyde readily adds ammonia to form acetaldehyde—ammonia. Diethyl amine [109-87-7] is obtained when acetaldehyde is added to a saturated aqueous or alcohoHc solution of ammonia and the mixture is heated to 50—75°C in the presence of a nickel catalyst and hydrogen at 1.2 MPa (12 atm). Pyridine [110-86-1] and pyridine derivatives are made from paraldehyde and aqueous ammonia in the presence of a catalyst at elevated temperatures (62) acetaldehyde may also be used but the yields of pyridine are generally lower than when paraldehyde is the starting material. The vapor-phase reaction of formaldehyde, acetaldehyde, and ammonia at 360°C over oxide catalyst was studied a 49% yield of pyridine and picolines was obtained using an activated siHca—alumina catalyst (63). Brown polymers result when acetaldehyde reacts with ammonia or amines at a pH of 6—7 and temperature of 3—25°C (64). Primary amines and acetaldehyde condense to give Schiff bases CH2CH=NR. The Schiff base reverts to the starting materials in the presence of acids. 

Naphtha desulfurization is conducted in the vapor phase as described for natural gas. Raw naphtha is preheated and vaporized in a separate furnace. If the sulfur content of the naphtha is very high, after Co—Mo hydrotreating, the naphtha is condensed, H2S is stripped out, and the residual H2S is adsorbed on ZnO. The primary reformer operates at conditions similar to those used with natural gas feed. The nickel catalyst, however, requires a promoter such as potassium in order to avoid carbon deposition at the practical levels of steam-to-carbon ratios of 3.5—5.0. Deposition of carbon from hydrocarbons cracking on the particles of the catalyst reduces the activity of the catalyst for the reforming and results in local uneven heating of the reformer tubes because the firing heat is not removed by the reforming reaction. 

Resorcinol Derivatives. Aminophenols (qv) are important intermediates for the syntheses of dyes or active molecules for agrochemistry and pharmacy. Syntheses have been described involving resorcinol reacting with amines (91). For these reactions, a number of catalysts have been used / -toluene sulfonic acid (92), zinc chloride (93), zeoHtes and clays (94), and oxides supported on siUca (95). In particular, catalysts performing the condensation of ammonia with resorcinol have been described gadolinium oxide on siUca (96), nickel, or zinc phosphates (97), and iron phosphate (98). 

Propionic acid is accessible through the Hquid-phase carbonylation of ethylene over a nickel carbonyl catalyst (104), or via ethylene and formic acid over an iridium catalyst (105). Condensation of propionic acid with formaldehyde over a supported cesium catalyst gives MAA directiy with conversions of 30—40% and selectivities of 80—90% (106,107). Catalyst lifetime can be extended by adding low levels (several ppm) of cesium to the feed stream (108). 

A low temperature catalytic process has been reported (64). The process involves the divalent nickel- or zero-valent palladium-catalyzed self-condensation of halothiophenols in an alcohol solvent. The preferred halothiophenol is -bromothiophenol. The relatively poor solubiHty of PPS under the mild reaction conditions results in the synthesis of only low molecular weight PPS. An advantage afforded by the mild reaction conditions is that of making telecheHc PPS with functional groups that may not survive typical PPS polymerization conditions. 

Mining. Numerous patents have advocated the use of alkanolamines in mining appHcations. Triethanolarnine has been used as a depressent in the flotation of copper (164), in the electrotwinning of gold (165), and as an aid in the froth flotation of nickel ores. Phosphate ore flotation has been improved through the use of a fatty acid condensate with ethanolamine (166). Beneficiation of tin ore has been accompHshed using fatty acid alkanolamides (167). 

Another significant use of 3-methylphenol is in the production of herbicides and insecticides. 2-/ f2 -Butyl-5-methylphenol is converted to the dinitro acetate derivative, 2-/ f2 -butyl-5-methyl-4,6-dinitrophenyl acetate [2487-01 -6] which is used as both a pre- and postemergent herbicide to control broad leaf weeds (42). Carbamate derivatives of 3-methylphenol based compounds are used as insecticides. The condensation of 3-methylphenol with formaldehyde yields a curable phenoHc resin. Since 3-methylphenol is trifunctional with respect to its reaction with formaldehyde, it is possible to form a thermosetting resin by the reaction of a prepolymer with paraformaldehyde or other suitable formaldehyde sources. 3-Methylphenol is also used in the production of fragrances and flavors. It is reduced with hydrogen under nickel catalysis and the corresponding esters are used as synthetic musk (see Table 3). 

Most commercial sorbic acid is produced by a modification of this route. Catalysts composed of metals (2inc, cadmium, nickel, copper, manganese, and cobalt), metal oxides, or carboxylate salts of bivalent transition metals (2inc isovalerate) produce a condensation adduct with ketene and crotonaldehyde (22—24), which has been identified as (5). 

Fractionation columns in tar-acid refineries are generally operated under vacuum and heated by high pressure steam or circulating hot oil. Calandtia in the reboders, condensers, mndown lines, and receiving tanks are constmcted of stainless steel, or, in the case of the condensers, of tin or nickel. 

Catalysts. In industrial practice the composition of catalysts are usuaUy very complex. Tellurium is used in catalysts as a promoter or stmctural component (84). The catalysts are used to promote such diverse reactions as oxidation, ammoxidation, hydrogenation, dehydrogenation, halogenation, dehalogenation, and phenol condensation (85—87). Tellurium is added as a passivation promoter to nickel, iron, and vanadium catalysts. A cerium teUurium molybdate catalyst has successfliUy been used in a commercial operation for the ammoxidation of propylene to acrylonitrile (88). 

In commercial practice, chlorination may be carried out either in batches or continuously. Glass-lined or nickel reactors may be used. Because certain metallic impurities such as iron catalyze ring chlorination and self-condensation, their presence must be avoided. The cmde product is purged of dissolved... 

Iron is added in small (usually 0.5—1.0 wt %) amounts to increase strength. More importantly, iron additions also enhance corrosion resistance, especially when precautions are taken to retain the iron in solution. Precipitation of the iron—nickel-rich phase does not result in strengthening and can cause degradation of corrosion resistance (47). A small (up to 1.0 wt %) amount of manganese is usually added to both react with sulfur and deoxidi2e the melt. These copper alloys are most commonly applied where corrosion resistance is paramount, as in condenser tube or heat exchangers. 

Chloro-a,/3-unsaturated aldehydes condense with ammonium thiocyanate to give isothiazoles (76EGP122249). 2,3-Diphenylcyclopropenone reacts with iV-sulfinyl-cyclohexylamine in the presence of nickel tetracarbonyl to give the isothiazolin-3-one 1-oxide (197) (79SST(5)345). Cholesteryl acetate reacts with trithiazyl trichloride in pyridine to give the isothiazolo steroid (198) (77JCS(P1)916). 

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

In a 5-1. three-necked flask, fitted with an eflicient stirrer (Note 1), a stopper, and a reflux condenser, are placed, in order, 184.2 g. (1 mole) of benzidine (Note 2), 500 ml. of commercial absolute ethanol, about 125 g. of Raney nickel, and 500 ml. of ethanol. The mixture is heated under reflux with stirring for a total of 15 hours (Note 3). The volume is brought to 3 1. with 05% ethanol, and about 150 g. of filter aid ( Super-Cel ) is added with stirring. The mixture is heated to boiling, filtered rapidly... 

The production of cobalt is usually subsidiary to that of copper or nickel and the methods employed differ widely, depending on which of these it is associated with. In general the ore is subjected to appropriate roasting treatment so as to remove gangue material as a slag and produce a speiss of mixed metal and oxides. In the case of arsenical ores, AS2O6 is condensed and provides a valuable byproduct. In the case of copper ores, the primary process... 

The Eschweiler reaction (formaldehyde and formic acid) has been used for the pyr-A-methylation of l-methyl-l,2,3,4-tetrahydro-j8-carboline, as has formaldehyde and hydrogen in the presence of Raney nickel. Tetrahydroharmine has been reported to react with benzaldehyde to yield a condensation product, C33H36N403, which is presumably a pyr-iV-substituted derivative (318). It is not known whether a similar condensation product of benzaldehyde with harm-aline is a C- or V-substituted derivative of harmaline. Conden-... 

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