Methylamine synthesis catalysts

The production of mono-, di-, and trimethylamines has a number of applications in the chemical industry. Monomethylamine is used in insecticides and surfactants, dimethylamine is used in rubber chemicals, and trimethylamine is used for choline chloride and biocides. Dimethylamine is produced to the greatest extent, followed by mono- and trimethylamine. The methylamines are produced by reaction of methanol and ammonia in the vapor phase over a dehydration catalyst at a temperature of 450°C and from atmospheric to approximately 20.4 atm pressure [30]. The methylamine synthesis reactions are ... 

The diversity in catalytic selectivity of substituted LDHs is clearly shown by Carja et al. s work on methylamine synthesis from methanol and ammonia (585b). It was found that monomethylamine is the favored product over Cu-containing MgAl-LDO, while dimethylamine is the main product over Fe-containing MgAl-LDO. When MgAl-LDO is used as the catalyst, ffimethylamine is preferentially synthesized. 

Ammonia has always been the starting material for the synthesis of aliphatic amines. Thus, processes have been developed for the condensation of NH3 with alkyl halides (Hoffman reaction) or with alcohols in the presence of various catalysts. The latter reachon, first discovered by Sabatier in 1909 [8, 9] is nowadays the main method of industrial production of light amines (e.g. methylamines 600 000 t/yr) [5]. 

A similar approach was taken for the synthesis of 45 by Miyaura. " Shaughnessy and Booth synthesized the water-soluble alkylphosphine 46, and found it to provide very active palladium catalysts for the reaction of aryl bromides or chlorides with boronic acids. The more sterically demanding ligand 47 was shown to promote the reactions of aryl chlorides with better results than 46. Najera and co-workers recently reported on the synthesis of di(2-pyridyl)-methylamine-palladium dichloride complexes 48a and 48b, and their use in the coupling of a variety of electrophiles (aryl bromides or chlorides, allyl chlorides, acetates or carbonates) with alkyl- or arylboronic acids very low catalyst loadings at Palladium-oxime catalysts 8a and 8b) have also been developed. In conjunction with... 

Furan itself can be used as the starting material for the synthesis of 1-methylpyrrole <2002MI179>. 7-AI2O3 was found to be an effective catalyst for the dehydration reaction between furan and methylamine to afford 1-methylpyrrole. A yield of 57.6% was achieved under the experimental conditions of a reaction temperature of 400 °C, a methylamine/ furan molar ratio of 1.5, and the molar flow rate of furan approximately 3-3.5 mmol/h. Furan was adsorbed onto Bronsted acid sites on the catalyst, while the methylamine was adsorbed onto Lewis acid sites. With this heterogeneous catalyst, the rate determining step of the mechanism was suggested to be the adsorption of furan on the Bronsted acid sites to form a ring-opened species, which is followed by the insertion of the adsorbed methylamine to form secondary amine intermediates. Further dehydration at the Lewis acid sites would yield 1-methylpyrrole. 

A special case in which a strongly basic catalyst was used to produce 4-methyl thiazole in a simplified reaction sequence (replacing a five step synthesis with a two step s>Tithesis) has been reported recently [146]. The catalysts (Cs loaded MFI and BEA) proved to be effective for the conversion of a ketone to an imine, more specifically acetone and methylamine into the corresponding imine. In the second step this imine is converted with SOt into 4-methyl thiazole (Scheme 17). Using Cs sulfate as the Cs source resulted in the... 

The aeylative cyclization of phenol with acetic anhydride was carried out over CeY type zeolites. The reaction mechanism is given in Fig. 4. At 380°C, the yield of 4-methyl coumarin was 75 % at 81% conversion of phenol. N-Methylpyrrolidine was synthesized from 1,4-butanediol and methylamine over Cr ZSM-5 and modified ZSM-5 catalysts at 300 C. The reaction mechanism is given in Fig. 5. The synthesis of a number of five- and six- membered heterocyclics have been depieted in Table 1. The reaction was carried out at 250-400°C at 30-80 hydrogen atm., under down-flow fixed bed conditions. The yield of N-methyl piperazine was 90% at 95% conversion over ZSM-5 catalysts. Similarly 2-methyl pyrazine and piperazine were synthesized from propylene glycol and ethylenediamine over HZSM-5 (Fig. 6). 

Enriched steam for the synthesis-gas generator (A) is produced in the series of sieve-plate contactors (E), (F), and (G). In (E) deuterium is transferred from methylamine liquid to methylamine vapor, reducing the deuterium content of the liquid from 10.916A to 1.06A while increasing that of the vapor from 1.02N to lOA. In (F) deuterium is transferred from methylamine vapor to water, increasing the deuterium content of the latter from N to 8A. This two-step transfer of deuterium from liquid methylamine leaving (C) to water leaving (F) is necessary to prevent chemical reaction between water and the catalyst dissolved in liquid methylamine. 

Metal cations Metal cation reduction Metal cations in MeAPO synthesis Metal corrosion prevention Metallocene, supported catalyst 24-0-05 Metallosilicates, microporous Methanol adsorption Methanol amination Methanol conversion Methanol dehydrogenation Methanol formation Methanol in alkylation 15-0-03 25-0-03 Methanol to hydrocarbons Methanol, reagent Methanol, steam reforming Methylamine in MFI synthesis N-Methylation, aniline Methylation, 4-methylbiphenyl Methylation, toluene, model 4-methylbiphenyl, methylation Methylcyclohexane cracking Methylcyclopentane hydroconversion Methylene silanes... 

In-situ IR experiments and a kinetic analysis revealed that, during the synthesis of methylamine on Bronsted acid mordenites, all methylammonium ions were formed in the micropores of the catalyst via a bimolecular complex of... 

Figure 7.19 Two-step synthesis of fatty acid glucamides by reductive alkylation of methylamine with glucose using Raney nickel as the hydrogenation catalyst to obtain Al-methyl glucamine, which is acylated by a base-catalyzed reaction with fatty acid methyl ester in a second step.

Pd-catalyzed reactions of amines provide convenient methods for the synthesis of tertiary amines, diamines, polyamines, and heterocyclic amines. Typically, the Pd-catalyzed reaction of A-methylbenzylamine with A-methylbutylamine gives A-butyl-A-methylben-zylamine (95%) along with methylamine (Scheme 2). The treatment of azetidine (3) with the palladium catalyst in the presence of 1,3-propanediamine (4) at 120 °C gives N-(3-aminopropyl)-l,3-propanediamine (5), which undergoes further Pd-catalyzed reaction with 3 to give the tetramine 6 (75%) (Scheme 3). 

Alkylation of Ammonia by Methanol The alkylation reactions of ammonia originally were discovered by Sabatier and Maihle in the early 1900s for the synthesis of higher amines. The chemistry had been adopted for methylamines in the 1930s when mono-, di-, and trimethylamines (MMA, DMA, and TMA) were coproduced in the following vapor phase reactions in the presence of a dehydrating catalyst ... 

Japan patent 1623 (1952) also claimed improvement in selectivity in favor of MMA and DMA with a Mg0/Si02 catalyst (1 1 ratio). A more recent development in catalytic technology is covered in West German patent DT-2916-060 for the use of zeolite to produce predominantly MMA and DMA. Although the cited patents, as well as many others, have claimed improvement in the catalysis for the synthesis of methylamines, no publication is available to show how many of these inven-... 

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