Methanol pressure

Kinetic and equilibrium studies of the sorption of methanol on various coals and on partially acety-lated samples of these coals have been used to elucidate a mechanism for this process. The data are interpreted in terms of partial acetylation blocking surface sites and perhaps interfering with intermolecular hydrogen bonding. It is proposed that the rate-determining step is a set of parallel, competing, second-order reactions involving transfer of methanol from the surface to the interior of the coal. All types of surface sites appear to participate, and the pressure-independent rate constant is considered to be the sum of the rate constants for each type of surface site. The dependence of the experimental rate constant on methanol pressure is a characteristic of the coal rank. 

In this equation dW/dt is the rate of sorption, k. is the experimental rate constant for sorption, W, is the equilibrium sorption, W is the amount of sorption at time t = t, and h is the experimental rate constant for desorption. Thus, the sorption rate was found to be proportional to the square of the concentration of unoccupied sites, and the desorption rate was proportional to the square of the concentration of occupied sites. These rate equations are not general solutions to Fick s law of diffusion. The experimental rate constants for sorption were found to be non-linearly dependent on methanol pressure and seemed to correlate with the amount of surface sorbed methanol in different ways for coals of various rank. 

Pressurized liquid extraction with 65% methanol Pressurized liquid extraction with methanol, ethanol, acetone, and aqueous methanol Sonication with methanol water TFA (100 100 2) for 30 min... 

Haglge et al. (75,174,175) report a further increase In the rate of product formation with increasing methanol pressure (up to 120 nm Hg) Herasyraowych and Knight (176a) indicate that there is a noticeable decline. 

Some very interesting features of the photolysis of methanol in the gas phase have been put forward by Hag ge et al. (75,174, 175) (as mentioned before, some of their results, and hence their Interpretation, have been questioned recently (176a)). The product quantum yields vary with methanol pressure. Hag ge et al. rationalized their results on the basis of eq. 26 where < i o is the quantum yield... 

The MTG reaction runs at a temperature around 400°C at a methanol pressure of several atmospheres, and uses a high activity catalyst. These are the optimal conditions for converting the olefins that form within the ZSM-5 crystals into paraffins and aromatics. 

Figure 1. Chromatograms showing that presence of alkenes is not necessary, once the catalyst has been activated. ( O.lg H-ZSM-5, methanol pressure 40 mbar, carrier 10 ml/min) A System 36 min on stream after 500°C in Ot. B Activation carried out. Ci After lOh flushing with N-> at 220°C. D The catalyst is active immediately after admission of metnanol, as shown by the effluent samples analyzed 3 and 7 min later. (There is a time lag about 3 min before admitted reactant is appearing in the effluent.)...

Figure 10. Mass spectra of products arising from reactions of TigC 2 with methanol, (a) obtained at very low partial pressure of methanol (b) obtained at a much higher methanol pressure. The number of methanol molecules associating onto TigCi2 is indicated. The reaction terminates at the eighth step. (Reproduced with permission from Prof. A. W. Castleman, Jr.)...

Fig. 50 Concentration profiles integrated over the z direction observed by interference microscopy during a methanol pressure step from 0 to 1 mbar. a Two-dimensional and b one-dimensional profiles in the crystal center along the x (fair spheres) and y (black spheres) directions. The times after onset of adsorption are indicated in b...

University of Manitoba, Canada, has published [3.27] results of laborattuy tests on direct conversion of methane to methanol. Pressures applied range from 30 to 70 bar, temperatures from 300 to 430° C. At space velocities comparable to those of commercialized processes, the conversion rate is between 4 and 10% of the natural gas feed only, and methanol selectivity is between 70 and 90%, the balance being mainly CO2. As oxidant, pure oxigen has been proposed. 

D16. We wish to do a normal batch distillation of methanol and water. The system has a still pot that acts as an equilibrium stage and a column with two equilibrium stages (total of three equilibrium contacts). The column has a total condenser, and reflux is returned as a saturated liquid. The column is operated with a varying reflux ratio so that x is held constant. The initial charge is F = 10 kmol and is 40 mol% methanol. We desire a final still-pot concentration of 8 mol% methanol, and the distillate concentration should be 85 mol% methanol. Pressure is 1 atm and CMO is valid. Equilibrium data are given in Table 2-7. 

Figure 5 Pressure drop as a function of modifier concentration. The pressure drop is directly proportional to viscosity. With pure carbon dioxide pressure drop is 9 bar. With pure methanol pressure drop is 200bar. Flow rate (5 ml min ), outlet pressure (125 bar), and temperature (35°C) were all held constant. Column 4.6 X 150 mm, 6pmoll Bl Cyano. Changing column inlet pressure has a significant impact on the compressibility of the carbon dioxide, which is a function of pressure. Without adequate dynamic compressibility compensation the delivery from the carbon dioxide pump will roll off as the pressure increases (making the total flow and actual composition unknowns).

An air-filled stainless-steel autoclave containing N,N-dipropargylbenzamide, a little 10% Pd-on-carbon, KI, and methanol pressurized to 4 bar with CO, and stirred at 25° for 24 h 1-benzoyl-3,4-bis(methoxycarbonylmethylene)pyrrolidine (Y 95%), in acetonitrile containing NEtj stirred at 25° for 18 h under N2 dimethyl 1-benzoylpyr-role-3,4-diacetate (Y 68%). F.e. inch N-alkyl-, N-carbalkoxy-, and N-tosyl-derivs. s. G.P. Chiusoli et al.. Synthesis 1989, 262-5. 

Octylphenol 9-mole ethoxylate ethoxy distribution Nomura Develosil ODS-5 C jj-bonded silica, 0.7 x 150 mm Methanol, pressure programmed, 255 C UV,215nm 27... 

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