Methanol, production catalyst

MPa (300—400 psig), using a Ni-based catalyst. Temperatures up to 1000°C and pressures up to 3.79 MPa (550 psia) are used in an autothermal-type reformer, or secondary reformer, when the hydrogen is used for ammonia, or in some cases methanol, production. 

Feedstock Purification Manufacture of Synthesis Gases Hydrogen, Ammonia, Methanol, product bulletin. United Catalysts, Inc., Louisville, Ky. 

Old processes use a zinc-chromium oxide catalyst at a high-pressure range of approximately 270-420 atmospheres for methanol production. 

Both new catalysts and new processes need to be developed for a complete exploitation of the potential of CO2 use [41]. The key motivation to producing chemicals from CO2 is that CO2 can lead to totally new polymeric materials and also new routes to existing chemical intermediates and products could be more efficient and economical than current methods. As a case in point, the conventional method for methanol production is based on fossil feedstock and the production of dimethyl carbonate (DMC) involves the use of toxic phosgene or CO. A proposed alternative production process involves the use of CO2 as a raw material (Figure 7.1)... 

The production of synthesis gas from natural gas and coal is the basis of the 33 000000 tpa methanol production and is also used in the production of ammonia. After removal of sulfur impurities, methane and water are reacted over a nickel oxide on calcium aluminate catalyst at 730 °C and 30 bar pressure. The reaction is highly endothermic (210 kJmol ) (Equation 6.6). 

Methanol production is carried out over a catalyst containing Cu and Zn oxide on alumina at around 300 °C and 100 atm according to Equation 6.7. It is actually thought that most of the methanol is produced from CO2 formed from reaction of CO with steam (Equation 6.8). 

Three-phase reactor systems are ideally suited for methanol production because of the ability to provide intimate contact between the gaseous phase reactants and the solid phase catalysts and to remove the large amounts of heat created by the high heats of reaction. In the three-phase system, an inert liquid phase circulates between the reactor and an external... 

A glass tube fixed-bed reactor was used as a closed static reactor. The cyclotron produced nC-radioisotope (Ti/2=20.4 min) was used for nC-labeled methanol production by radiochemical process. The nC-labeled methanol (shortly nC-methanol, - 3pmol, -600 MBq) was then introduced into 250 mg of zeolite at ambient temperature by He gas flow. Afterwards, equivalent volume of liquid methyl iodide was injected into nC-methanol to have mixture of methanol and methyl iodide and introduced into catalyst for investigation of methyl iodide influence. After adsorption (2 min), the catalyst was heated up to the required temperature. 

The above reaction can be carried out in the presence of a variety of catalysts including Ni, Cu/Zn, Cu/SiO, Pd/SiO, and Pd/ZnO. In the case of coal, it is first pulverized and cleaned, then fed to a gasifier bed where it is reacted with oxygen and steam to produce the syngas. A 2 1 mole ratio of hydrogen to carbon monoxide is fed to a fixed-catalyst bed reactor for methanol production. Also, the technology for making methanol from natural gas is already in place and in wide use. Ciurent natural gas feedstocks are so inexpensive that even with tax incentives renewable methanol has not been able to compete economically. 

Methanol was first produced commercially in 1830 by the pyrolysis of wood to produce wood alcohol. Almost a century later, a process was developed in Germany by BASF to produce synthetic methanol from coal synthesis gas. The first synthetic methanol plant was introduced by BASF in 1923 and in the United States by DuPont in 1927. In the late 1940s, natural gas replaced coal synthesis gas as the primary feedstock for methanol production. In 1966, ICI announced the development of a copper-based catalyst for use in the low-pressure synthesis of methanol. 

Figure 7 depicts a simplified block flow diagram (BFD) for a typical biodiesel production process using base catalysis. In the first step, methanol and catalyst (NaOH) are mixed with the aim to create the active methoxide ions (Figure 4, step 1(b)). Then, the oil and the methanol-catalyst solution are transferred to the main reactor where the transesterification reaction occurs. Once the reaction has finished, two distinct phases are formed with the less dense (top) phase containing the ester products and unreacted oil as well as some residual methanol, glycerol, and catalyst. The denser (bottom) layer is mainly composed of glycerin and methanol, but ester residues as well as most of the catalyst, water, and soap can also be found in this layer. 

Iron molybdates, well known as selective methanol oxidation catalysts, are also active for the propene oxidation, but not particularly selective with respect to acrolein. Acetone is the chief product at low temperature (200°C), whereas carbon oxides, besides some acrolein, predominate at higher temperatures [182,257], Firsova et al. [112,113] report that adsorption of propene on iron molybdate (Fe/Me = 1/2) at 80—120°C causes cation reduction (Fe3+ -> Fe2+) as revealed by 7-resonance spectroscopy. Treatment with oxygen at 400°C could not effect reoxidation (in contrast to similarly reduced tin molybdate). The authors assume that this phenomenon is related to the low selectivity of iron molybdate. 

Ammonia, Hydrogen, and Methanol Production The ammonia synthesis catalyst is metallic iron promoted with AljO,. K 0. MgO. and CaO. The hydrogen-producing (methane reforming) catalyst is supported nickel. The methanol synthesis catalyst is ZnO promoted with Cr Oj or Cu(l>—ZnO promoted with CrjOl or AUOi. The respective reactions are cited as follows. 

Deng and co-workers have also applied the cinchona derivatives to the kinetic resolution of protected a-amino acid N-carboxyanhydrides 51 [48]. A variety of alkyl and aryl-substituted amino acids may be prepared with high se-lectivities (krei=23-170, see Scheme 10). Hydrolysis of the starting material, in the presence of the product and catalyst, followed by extractive workup allows for recovery of ester, carboxylic acid, and catalyst. The catalyst may be recycled with little effect on selectivity (run 1, krei=114 run 2, krei=104). The reaction exhibits first-order dependence on methanol and catalyst and a kinetic isotope effect (A MeOH/ MeOD=l-3). The authors postulate that this is most consistent with a mechanism wherein rate-determining attack of alcohol is facilitated by (DHQD)2AQN acting as a general base. 5-Alkyl 1,3-dioxolanes 52 may also... 

Thus a variety of hydrocarbons, ranging from natural gas to coal, are used in methanol production. Regardless of the feedstock used to prepare the synthesis gas, it is necessary to remove sulfur so that the converter catalyst is not poisoned. Before natural gas or naphtha is reformed, the feedstock is desulfurized. In the partial oxidation and coal gasification processes, the feedstock is first oxidized and the resulting synthesis gas is desulfurized before entering the converter. 

Methanol production today is not a sustainable process but is part of a petrochemical route for conversion of fossil carbon into chemicals and fuels (see Section 5.3.3). It has to be emphasized that a one-to-one upscaling of existing industrial methanol synthesis capacities for fuel production is not useful. This is mainly because the current industrial process has not been developed and optimized under the boundary conditions of conversion of anthropogenic C02, but rather for synthesis gas feeds derived from fossil sources such as natural gas or coal. The switch to an efficient large-scale methanol synthesis with a neutral C02 footprint is still a major scientific and engineering challenge, and further research and catalyst and process optimization is urgently needed to realize the idea of a sustainable methanol economy. ... 

Figure 5.3.7 The variation of CO and methanol production rates with space velocity (A) and methanol synthesis rates on promoted CuZn-based catalysts derived from hydrotalcite and Malachite precursors (B). Reaction conditions 200 mg catalyst, 30 bar, 230°C, 3 1 H2 C02.

Liu G, et al. The rate of methanol production on a copper-zinc oxide catalyst - the dependence on the feed composition. J Catal. 1984 90(l) 139-46. 

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