Methanol from carbon dioxide

A little later, Russell et al.19 tried to obtain methanol from carbon dioxide by electrolysis. Reduction of carbon dioxide to formate ion took place in a neutral electrolyte at a mercury electrode. On the other hand, formic acid was reduced to methanol either in a perchloric acid solution at a lead electrode or in a buffered formic acid solution at a tin electrode. The largest faradaic efficiency for methanol formation from formic acid was ca. 12%, with poor reproducibility, after passing 1900 C in the perchloric acid solution at Pb in a very narrow potential region (-0.9 to -1.0 V versus SCE). In the buffered formic acid solution (0.25 M HCOOH + 0.1 M... 

The reaction rate for the first reaction for the production of methanol from carbon dioxide is given as follows ... 

Scheme 9.8 A mechanism for the synthesis of methanol from carbon dioxide on Au/Fe203.

The synthesis of methanol from carbon dioxide and hydrogen is a reaction that has been a well studied in recent years [119 -127) and results of kinetic experiments show that CO2 is converted directly to methanol under synthesis conditions and that the overall reaction consists of the following two parallel reactions [ 12 133). 

The process just described may also be operated at somewhat lower pressures and temperatures than outlined by using some of the more recent copper-based catalysts. Energy saved by doing this achieves some production economies. It is also possible, with an extra mole of hydrogen, to produce methanol from carbon dioxide (Eq. 19.17). 

A method of chemically synthesizing reduced products including methanol from carbon dioxide and hydrogen has been developed. The method utilizes a metal hydride foil membrane as a continuous source of reactive surface hydrogen atoms and an electrostatic field to enhance the adsorption of carbon dioxide and bicarbonate onto the hydrogen rich surface. The subsequent chemical(rather than electrochemical) reaction between the adsorbed carbon dioxide and surface hydrogen/metal hydride results in the formation of reduced products. 

Current developments in carbon dioxide reduction research is not enough for the real implementation of the process. The maximum yield has been reached up to some micromoles. Let s look at the present scenario, with the current pace, 1.1 x 108 kg of TiC>2 would be required for the production of methanol from carbon dioxide and water, assuming a catalyst activity of 1 pm ol product gcat 1 h"1 and production rate 1kg s"1 [19]. 

Nasution, H. W. Pumama, E. Riyani, K. Gunlazuardi, J. Effect of copper species in a photocatalytic synthesis of methanol from carbon dioxide over copper-doped titania catalysts. World. Appl. Sci. J., 2009, 6,112-122. 

EFFECT OF PREPARATION VARIABLES ON CATALYTIC BEHAVIOUR OF COPPER/ZIRCONIA CATALYSTS FOR THE SYNTHESIS OF METHANOL FROM CARBON DIOXIDE... 

Barnabas et al. [51] have discussed an experimental design approach for the extraction of polyaromatic hydrocarbons from soil using supercritical carbon dioxide. They studied 16 different polyaromatic hydrocarbons using pure carbon dioxide and methanol modified carbon dioxide. The technique is capable of determining down to lOOmg kgy1 polyaromatic hydrocarbons in soils. 

Hawthorne et al. [53] compared supercritical extraction with chlorodifluoromethane, nitrous oxide and carbon dioxide for the extraction of polychlorobiphenyls and polyaromatic hydrocarbons from soil. Chlorodifluoromethane provided the highest recoveries while methanol modified carbon dioxide gave a 90% recovery of polychlorobiphenyls from soil. 

Snyder et al. [94] compared supercritical extraction with classical sonication and Soxhlet extraction for the extraction of selected organophosphorus insecticides from soil. Samples extracted with supercritical carbon dioxide modified with 3% methanol at 350atm and 50°C gave a =85% recovery of Diazinon (diethyl-2-isopropyl-6-methyl-4-pyrimidinyl phosphorothiodate or 0,0 diethyl-0-(2-isopropyl-6-methyl-4-pyrimidyl) phosphorothioate). Ronnel (or Fenchlorphos) 0,0-dimethyl-0-2,4,5 trichlorophenol phosphorothiodate), Parathion ethyl (diethyl-p-nitrophenyl (phosphorothioate), Tetrachlorovinphos (trans,-2-chloro-l-(2,4,5 trichlorophenyl) vinyl (chlorophenyl-O-methylphenyl phosphorothioate) and Methiadathion. Supercritical fluid extraction with methanol modified carbon dioxide has been applied to the determination of organophosphorus insecticides in soil [260]. 

A new approach to the analysis of the carcinogenic TSNA in moist snuff tobacco is based on SFE with methanol-modified carbon dioxide. Extracted TSNA are trapped across a glass cartridge filled with Tenax GR, from which they are subsequently released by thermal desorption and analyzed by capillary GC-TEA LOD was <2 ng/g. The technique is fast, reproducible, highly selective and sensitive617. SFE with carbon dioxide was also used in the analysis of TSNA in smokeless tobacco. It revealed the presence of higher levels of 4-(methylnitrosamino)-l-(3-pyridyl)-l-butanone (300) than had been determined earlier by conventional methods618. 

In DMFCs, Scott, Taama, and Argyropoulos [117] changed the PTFE content (from 0 to 40 wt%) of the anode DL (E-TEK type A CC) in order to observe how this affected the methanol and carbon dioxide transport through the DL. At very high levels of PTFE, the performance of the cell decreases due to an increase in resistance losses. On the other hand, when an untreated CC was used, the observed performance was the lowest of all the materials investigated. In this study it was concluded that the ideal amount of hydro-phobic agent for the anode DL is around 13-20 wt% (see Figure 4.17). 

Figure 5. Oxidation of methanol to carbon dioxide by a three-enzyme system consisting of alcohol (ADH), aldehyde (AldDH), and formate (FDH) dehydrogenases. Each enzyme is NAD+-dependent, and the NAD+ is regenerated by the anode via a redox mediator system. Redrawn with permission from ref 82. Copyright 1998 Elsevier Science S.A.

So far, no reference has been made to the presence of more than one phase in the reactor. Many important chemicals are manufactured by processes in which gases react on the surface of solid catalysts. Examples include ammonia synthesis, the oxidation of sulphur dioxide to sulphur trioxide, the oxidation of naphthalene to phthalic anhydride and the manufacture of methanol from carbon monoxide and hydrogen. These reactions, and many others, are carried out in tubular reactors containing a fixed bed of catalyst which may be either a single deep bed or a number of parallel tubes packed with catalyst pellets. The latter arrangement is used, for exjimple, in the oxidation of ethene to oxiran (ethylene oxide)... 

Daicel Chemical Industries in Japan patented a promising phosgene-free process involving the reaction of an aliphatic diamine with dimethyl carbonate (DMC) to produce carbamate esters, which are then thermally converted to the corresponding aliphatic diisocyanates [38] (Scheme 5.4). It is noteworthy that this process could be a total phosgene-free process since the reactant, DMC, can be made directly from methanol and carbon dioxide (or urea) and eliminates the use of phosgene [39]. 

This is in agreement with the observed increase in methanol decomposition during the intervention, which may well arise from the presence of an excellent hydrogen acceptor, such as carbon dioxide. [11,12,16,17]. Together with the presence of alkali cation, co-adsorption of methanol and carbon dioxide could possibly form a methyl carbonate species which would rapidly undergo decomposition to carbon monoxide and hydrogen. 

Methanol and Carbon Dioxide. Isolation and quantitative determination of these degradation products could be accomplished by analyzing the reaction mixture obtained from a separate oxidation experiment under standard conditions. A sample of 5 mmoles of 6,6 -bicreo-sol was dissolved in 50 ml. 0.2N aqueous NaOH corresponding to 2 mole equivalents alkali. 

FIGURE 12 Chromatograms of the chiral resolution of coumachlor on vancomycin CSP using 15% methanol in carbon dioxide under the SFC mode. (From Ref. 56.)... 

Thebaine, codeine and morphine from poppy straw (Papaver somniferum) were extracted with carbon dioxide and various polar modifiers at 20 MPa and 40.5 °C. Kinetic extraction curves for morphine showed that 50% methanol in carbon dioxide was necessary in order to achieve quantitative yields in less than 20 min. A mixture of 25% methanol, 0.22% methylamine and 0.34% water had the same effect as 50% methanol in the catbon dioxide. However, it was also reported that, in spite of its strong extraction power, the methylamine-water mixture had a major drawback in that morphine in the presence of the amine degraded in the presence of light. Hence, carbon dioxide-methanol-water mixtures were investigated increasing the water content in the extraction fluid dramatically enhanced the extraction rate for thebaine [29]. 

S-i Fujita, Bhanage BM, Ikushima Y et al (2001) Synthesis of dimethyl carbonate from carbon dioxide and methanol in the presence of methyl iodide and base catalysts under mild conditions effect of reaction conditions and reaction mechanism. Green Chem 3(2) 87-91... 

Bhanage BM, S-i Fujita, Ikushima Y et al (2003) Synthesis of dimethyl carbonate and glycols from carbon dioxide, epoxides and methanol using heterogeneous Mg containing smectite catalysts effect of reaction variables on activity and selectivity performance. Green Chem 5(1) 71—75... 

Saito M, et al. Development of copper/zinc oxide-based multicomponent catalysts for methanol synthesis from carbon dioxide and hydrogen. Appl Catal A Gen. 1996 138(2) 311—18. 

Values of Activation Energies of Methanol Synthesis from Carbon Monoxide, Efk), and from Carbon Dioxide, E,(k ), and Adsorption Enthalpies AH and Entropies AS Derived from the Kinetic Model Utilizing Constants in Table IX ... 

Much of the early work done on the biochemistry of methane formation supported the position that methane is formed almost exclusively by reduction of carbon dioxide. However, it was shown with methanol and a species of Methanosarcina that less than 1% of the methane is derived from carbon dioxide (Schnellen, 1947 Stadtman and Barker, 1949). According to the mechanism proposed by van Neil for catabolism of acetic acid, all of the acid should be... 

Fig. 1 Separation of benzylamines (a) On a Deltabond Octyl column (100 X 2 mm, 5 tm) using pure carbon dioxide (0.5 mL/min) at 40°C and 180 bar (b) on a Diol column (100 X 2 mm, 7 tm) using 5% methanol in carbon dioxide (0.5 mL/min) at 40°C and 182 bar (c) on a Diol column (250 X 4.6 mm, 5 tm) using 10% methanol (containing 0.6% isopropylamine) in carbon dioxide (2 mL/min) at 40°C and 200 bar. Reprinted from /. Chromatogr. A Vol. 785, T. A. Berger, Separation of polar solutes by packed column supercritical fluid chromatography, p. 9. Copyright 1997, with permission from Elsevier Science.)...

There are two possible pathways to homologate methanol with carbon dioxide the CO2 insertion path and CO insertion path (Scheme 2). As for the former, Fukuoka et al. reported that the cobalt-ruthenium or nickel bimetallic complex catalyzed acetic acid formation from methyl iodide, carbon dioxide and hydrogen, in which carbon dioxide inserted into the carbon-metal bond to form acetate complex [7]. However, the contribution of this path is rather small because no acetic acid or its derivatives are detected in this reaction. Besides, the time course... 

In order to synthesize gasoline effectively from carbon dioxide through one-pass reaction system, methanol synthesis catalyst was improved. Pd and Ga were added to Cu-Zn based catalyst to optimize the state of Cu during the reaction. As the result, the space-time yield (STY) of methanol from CO2 was 1,410 gd h at 270, 80 atm and SV=18,800 /h. In second stage reactor in which H-Ga or Al-silicate was packed, methanol was converted to gasoline. Maximum selectivity to gasoline fraction was 54.4 % and STY was 312 gl h at 320 C and 15 atm. 

Methanol synthesis from carbon dioxide on CuO-ZnO-AlaOa catalysts... 

---