Chromite, catalyst synthesis

High pressure processes P > 150 atm) are catalyzed by copper chromite catalysts. The most widely used process, however, is the low pressure methanol process that is conducted at 503—523 K, 5—10 MPa (50—100 atm), space velocities of 20, 000-60,000 h , and H2-to-CO ratios of 3. The reaction is catalyzed by a copper—zinc oxide catalyst using promoters such as alumina (31,32). This catalyst is more easily poisoned than the older copper chromite catalysts and requites the use of sulfiir-free synthesis gas. 

Pentanediol (PDO) holds promise for being used in the synthesis of polyesters. It has been synthesized from GVL in the presence of a copper chromite catalyst. At 150 °C and 20.3-30.4 MPa hydrogen pressure, 78.5% PDO was produced together with 8.1% 1-pentanol. ... 

Synthesis from Citronellol. ( )-Citronellal can also be obtained by dehydrogenation of citronellol under reduced pressure with a copper chromite catalyst [64]. 

We have developed a multimetallic catalyst for the large scale synthesis of sterically hindered mono-N-alkylanilines with very good selectivity and high catalytic activity. In contrast to copper chromite catalysts which allow the N-alkylation only with primary alcohols, the doubly promoted Pt/Si02 catalysts described here are useful for the reaction of ortho-substituted anilines with both primary and secondary alcohols. 

The condensation of a,j8-diketones with 1,2-diamines is a classical route for the synthesis of alkyl- and arylpyrazines. For example, good yields of dihydropyrazines are obtained from reaction of 2,3-dioxo-alkanes andethylenediamine dehydrogenation over a copper chromite catalyst at 300° then gives 3-alkyl-2-methylpyrazines (Scheme 1). Attempts to carry out the dehydrogenation using a variety of milder and more convenient laboratory procedures were not successful.100,110... 

The influence of the C02/C0 ratio on the synthesis has been embedded in kinetic equations only recently. The early kinetic equations for the high-pressure Zn0/Cr203 catalyst did not contain a C02-dependent term at all, perhaps because the effects of C02 were not significant when zinc chromite catalysts were used Natta et al. (57) proposed the rate equation for the Zn0/Cr203 catalyst at temperatures 300-360°C as follows ... 

Another commercial aldehyde synthesis is the catalytic dehydrogenation of primary alcohols at high temperature in the presence of a copper or a copper-chromite catalyst. Although there are several other synthetic processes employed, these tend to be smaller scale reactions. For example, acyl halides can be reduced to the aldehyde (Rosemnund reaction) using a palladium-on-barium sulfate catalyst. Formylation of aryl compounds, similar to hydrofomiylation, using HCN and HQ (Gatterman reaction) or carbon monoxide and HQ (Gatterman-Koch reaction) can be used to produce aromatic aldehydes. 

The condensation of a, dicarbonyl compounds (49) with aj3-diamino compounds (50), which proceeds through the dihydropyrazine (51), has been much used for the synthesis of alkyl- and arylpyrazines (52). These reactions are usually carried out in methanol, ethanol, or ether in the presence of sodium or potassium hydroxide. The dihydropyrazines may be isolated, or oxidized directly to the pyrazine. Dehydrogenating agents that have been employed include oxygen in aqueous alkali (329), air in the presence of potassium hydroxide (330), sodium amylate in amyl alcohol (330a), alcoholic ferric chloride (24), and copper chromite catalyst at 300° (331) (see also Section 1). Pyrazines prepared by this method and modifications described below are listed in Table II.8 (2, 6, 24, 60, 80,195, 329-382) and some additional data are provided in Sections VI. 1 A, VlII.lA(l), and IX.4A(1). 

Keywords Dimethylethylamine synthesis, monoethylamine reaction with methanol, copper or copper chromite catalysts, alkaline or alkaline-earth modifiers. 

In the first part of our work, we examined the properties of a copper chromite catalyst for the selective synthesis of dimethylethylamine (DMEA) from monoethyiamine (MEA) and methanol (MeOH). Under our experimental conditions at 230°C, this catalyst... 

Synthesis from anisole and propionic acid derivatives. Anisole is converted into 4-methoxypropiophenone by Friedel-Crafts acylation with propionyl chloride or propionic anhydride. The ketone is hydrogenated to the corresponding alcohol with a copper chromite catalyst. The alcohol is dehydrated in the presence of acidic catalysts to a cis/trans mixture of anetholes [163b]. 

This study reports improved stabilities of skeletal Cu catalysts for use in organic synthesis reactions. The promoted skeletal Cu catalysts have been characterised by measuring their resistance to structural rearrangement in caustic solutions, thermal stabilities and activities for the reactions of methanol dehydrogenation and methyl formate hydrogenolysis. Comparisons have been made with an unpromoted skeletal Cu catalyst and a commercial coprecipitated copper chromite catalyst. 

In the pre-World War II days there was little work done at Princeton on synthesis of catalysts. Copper catalysts were made by reduction of Kahlbaum copper oxide, the iron ammonia catalysts were obtained from the Fixed Nitrogen Laboratory through the courtesy of Dr. Paul Emmett, the nickel on kleselguhr catalyst was obtained from DuPont. Platinum on asbestos was made in the laboratory by soaking asbestos with chloroplatinic acid and then igniting it, mixed chromite catalysts were precipitated and calcined and a study was made. 

DL-Serine is synthesized in 51% over-all yield by Redemann and Icke s (661) modification of the method of Dunn et al. (212). Ethoxy-acetaldehyde (A) is prepared in aqueous solution by oxidizing ethylene glycol monoethyl ether (ethyl cellosolve) with copper chromite catalyst at 310-330°C. DL-Serine is prepared by reaction of NaCN, NH Cl and NH, in methanol with (A) and hydrolysis of the intermediate ethoxy nitrile with HBr. Other methods for the preparation of ethoxyacet-aldehyde have been described by the authors referred to by Dunn (203, p. 21) and by other workers (196-198, 412, 226). This synthesis... 

First methanol synthesis plant, opened by BASF at Merseburg, using a zinc chromite catalyst... 

Following the introduction of a copper chromite catalyst based on the DuPont recipe for zinc chromite, a further copper catalyst was developed from experimental work related to the high-pressure methanol synthesis process." " ... 

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