68621-77-2

Upstream product

• 67-56-1 methanol 
• 201230-82-2 carbon monoxide 
• 121-14-2 2,4-dinitrotoluene 
• 95-80-7 4-methylbenzene-1,3-diamine 
• 13509-27-8 methyl phenyl carbonate 
• 79-22-1 methyl chloroformate 
• 616-38-6 carbonic acid dimethyl ester 
• 124-38-9 carbon dioxide 

Relevant academic research and scientific papers

A green route to polyurethanes: Oxidative carbonylation of industrially relevant aromatic diamines by CO2-based methyl formate

The oxidative carbonylation of toluene-2,4-diamine (TDA) with methyl formate (MF), which can be produced from CO2, provides a possible route for the non-phosgene production of isocyanate precursors and enables a valuable utilization of the greenhouse gas. Extensive analysis of the product spectrum has provided detailed insight into the reaction network leading to the target product toluene-2,4-dicarbamate (TDC) and the most important side products. The most prominent one has been identified as methylene-bridged tetracarbamate 5, which is also an interesting precursor for applications in polyurethane chemistry. The side products are caused by three different reaction paths: N-formylation by MF, condensation with in situ formed formaldehyde, and N-methylation by in situ formed dimethyl carbonate (DMC). The influence of the catalyst on product distribution was evaluated for PdCl2/CuCl2 and a large number of heterogeneous Pd-catalysts. The oxidic support materials ZrO2, CeO2 and SiO2 were found to partially suppress the undesired side reactions leading to higher yields of TDC and tetracarbamate 5. The ratio of TDC to 5 was demonstrated to be affected significantly by the choice of the support. The synthetic protocol was extended to the synthesis of dicarbamates from 4,4′-methylenedianiline (MDA) and 2,4-diaminomesitylene (17). These results encourage further investigations into the design of selective catalysts for the production of isocyanate precursors from CO2 as a C1 source.

Zr-MOF-808@MCM-41 catalyzed phosgene-free synthesis of polyurethane precursors

In this work, a catalytic method is presented for the synthesis of aromatic carbamates from aromatic amines using dimethyl carbonate instead of phosgene as a green and safe reaction process. Microcrystalline Zr-MOF-808 is reported as an active and efficient heterogeneous catalyst for the selective carbamoylation of anilines and industrially relevant aromatic diamines, under mild reaction conditions with near quantitative yields. We have accomplished the selective growth of well-dispersed Zr-MOF-808 nanocrystals within the mesoporous material MCM-41. A superior catalytic performance of the Zr-MOF-808@MCM-41 is demonstrated that together with increased stability stands out as an advantageous heterogeneous catalyst for polyurethane production. In situ FTIR studies have allowed a better understanding of the reaction pathway at the molecular level when the active MOF catalyst is present.

Direct Catalytic Synthesis of N-Arylcarbamates from CO2, Anilines and Alcohols

The direct catalytic synthesis of carbamates from CO2, amines and methanol was achieved by controlling both the reaction equilibrium and the reactivity of the three components. The combination of CeO2 and 2-cyanopyridine was an effective catalyst, providing various carbamates including N-arylcarbamates in high selectivities.

SILICA-BASED ZINC CATALYSTS. THEIR PREPARATION AND USE IN THE ALKOXYCARBONYLATION OF AMINES

The present invention relates to silica-based heterogeneous zinc compounds which are suitable as catalysts in the reaction of amines with dialkyl carbonates to produce carbamates. The catalysts have the formula [SiO2]-CH2-CHR-X-COOZn[Y], wherein [SiO2] represents a silica carrier selected from the group consisting of ordered mesoporous silica and irregular amorphous narrow pore silica, R represents a moiety selected from the group consisting of hydrogen, -CH3, and -CH2CH3, preferably hydrogen, X is an aliphatic chain of 2 to 11 carbon atoms that optionally comprises ether moieties and [Y] represents a mono anion. The invention is also directed towards a method for the preparation of the aforementioned compounds and towards method for the alkoxycarbonylation of amines.

Phosgene-free synthesis of carbamates using co2 and titanium alkoxides

A facile one-pot, phosgene-free method for the synthesis of N-phenylcarbamates is developed. Using this method, various aromatic carbamates could be prepared from aromatic amines, CO2 and metal alkoxides. Aniline reacted with titanium methoxide (Ti(OMe)4)) in the presence of CO2 (5 MPa) to give methyl N-phenylcarbamate in 85% yield, in 20min. Titanium residue could be regenerated by reaction with dimethyl carbonate at 220 °C for 16 h.

ONE-POT PRODUCTION OF CARBAMATES USING SOLID CATALYSTS

The invention relates to the production of carbamates in a single reactor (one-pot) using solid catalysts, involving the reaction between at least one nitro compound, an organic carbonate of formula (OR)(OR')C=O, a gas selected from hydrogen gas and a mixture of gases containing hydrogen and hydrogen precursor compounds, and a catalyst that has at least one metallic oxide and can also contain an element of groups 8, 9, 10 and 11 of the periodical table. The carbonates obtained can be transformed into their corresponding isocyanates.

ONE-POT PRODUCTION OF CARBAMATES USING SOLID CATALYSTS

The invention relates to the production of carbamates in a single reactor (one-pot) using solid catalysts, involving the reaction between at least one nitro compound, an organic carbonate of formula (OR)(OR′)C═O, a gas selected from hydrogen gas and a mixture of gases containing hydrogen and hydrogen precursor compounds, and a catalyst that has at least one metallic oxide and can also contain an element of groups 8, 9, 10 and 11 of the periodical table. The carbonates obtained can be transformed into their corresponding isocyanates.

PREPARATION OF CARBAMATES WITH SOLID CATALYSTS

Procedure for preparing carbamates comprising reaction between at least: an amine or polyamines, an organic carbonate of formula (OR)(OR')C=O, a catalyst formed at least by a support selected from among at least a metal oxide, a microporous material, a mesoporous material, an anionic laminar compound of the hydrotalcite type or derivatives thereof or an organic polymer and which may also contain a metal from groups 8, 9, 10 and 11 of the periodic system. The carbamates obtained may be converted into the corresponding isocyanates thereof.

Gold-catalyzed phosgene-free synthesis of polyurethane precursors

(Figure Presented) Golden catalyst: In a two-step one-pot catalytic process gold nanoparticles supported on CeO2 are able to convert nitroaromatics into aromatic carbamates, thereby providing an alternative phosgene-free route towards aromatic polyurethanes (see figure).

Carbonylation of dinitrotoluene to dimethyl toluenedicarbamate; high efficiency of phosphorus acids as promoters for the palladium-phenanthroline catalytic system

Phosphorus acids are excellent promoters for the palladium-phenanthroline catalyzed carbonylation of 2,4-dinitrotoluene to 2,4-toluenedicarbamate. For the first time, all intermediate nitrocarbamates and aminocarbamates have been independently synthesized and their amount after every catalytic reaction precisely quantified. An extensive optimization of all experimental variables has been carried out. The best acids are phenylphosphonic and 4-tolylphosphonic acids. The addition of 2,2-dimethoxypropane as an internal drying agent is highly beneficial. The addition of an amine derived from the starting dinitroarene increases both rate and selectivity of the carbonylation reaction. The complexes [Pd(Phen)2] [SbF6] and [Pd(Phen) 2][BArF4] [ArF = 3,5-(CF 3)2C6H3] have been prepared for the first time. The latter displays a markedly higher solubility than all other [Pd(Phen)2]2+ complexes. The effect of several possible promoters has also been investigated. Under the optimized experimental conditions, a 77.6% selectivity in dicarbamate was obtained when working at a molar ratio dinitrotoluene/Pd = 2920. At the end of the reaction, the dicarbamate spontaneously precipitates out of the solution in high yields upon cooling, with no inclusion of the acid promoter or of phenanthroline. 2,6-Dinitrotoluene can also be efficiently carbonylated to the corresponding dicarbamate.