Rate of MeOH

The oxygenate catalyst volume is also related to the module of the gas from the synthesis gas production (Fig. 7). Mininum oxygenate catalyst volumes are obtained at high modules. The reason is simply that the reaction rate of MeOH formation depends on the partial pressure of hydrogen (ref. 7). 

WHSV is defined as the ratio of mass flow rate of MeOH with mass of catalyst. It is inversely proportional to contact time. According to Ref. [66], the increase of contact time has the same effects on products distribution as the temperature does. Selectivity to light olefins increases... 

For tbe rate of proton transfer between the lyonium ion (MeOH2 ) and solvent (MeOH) and the lyate ion (MeO ) and solvent, Grunwald et al. give this result ... 

Mg, MeOH or Mg(OMe)2 iri MeOH. The acetate is cleaved in the presence of the benzoate and pivaloate (76-96% yield). The relative rates of cleavage are as follows p-nitrobenzoate > acetate > benzoate > pivaloate acetamide. Tertiary acetates are not cleaved. ... 

In terms of the final loss of aniline after ring closure, the fact that reactions using EtsN and BU3N, (ammonium ion as proton source) occurred at the same rate as the reactions with methoxide base (MeOH as proton source) suggested a lack of general acid catalysis. Also, it was found that varying the amount of available acid did not change the rate of cyclization appreciably. ... 

Where Br nucleophilically promotes the Br+/OTf- elimination to generate free Br2 and cyclohexene. This process requires that the rate of solvolysis of 4 be linearly dependent on [Br ]. However, control (ref. 15) kinetics experiments indicate that the rate constant for solvolysis of 4 in HOAc or MeOH are independent of Br" thus generation of free Br2 must occur after the rate limiting step. This nicely confirms the previous conclusion based upon the invariance of the n0a+10hV9h ratio on [Br]. 

The alkali-catalysed methanolysis of poly(2,2-bis(4-hydroxyphenyljpropane carbonate) (PC) in a mixture of methanol (MeOH) and toluene or dioxane was studied. The treatment of PC in meOH, with a catalytic amount of sodium hydroxide, yielded only 7% bisphenol A. Using a mixed solvent of MeOH and toluene completely depolymerised PC to give 96% free bisphenol A in solid form and dimethyl carbonate in solution. The eharaeteristies of the catalysis are discussed together with the pseudo-first rate kinetics of the depolymerisation. The reaetion eonditions were investigated to facilitate the reeyeling of PC plasties. 17 refs. 

In our first experiment we decided to test the conversion of sunflower oil into biodiesel (16). Treatment of sunflower oil (1) with NaOMe in MeOH results in formation of a mixtme of fatty acid methyl esters (FAME), also known as biodiesel, and glycerol (2) (Figme 4.3). The reaction was performed with a six-fold molar excess of methanol with respect to sunflower oil at elevated temperatures (60°C) using a basic catalyst (NaOMe, 1% w/w with respect to sunflower oil). The CCS was equipped with a heating jacket to ensure isothermal conditions. The sunflower oil was preheated to 60°C and was pumped at 12.6 ml/min into one entrance of the CCS. Subsequently, a solution of NaOMe in MeOH was introduced through the other entrance at a flow rate of 3.1 ml per minute. After about 40 minutes, the system reaches steady state and the FAME containing some residual sunflower oil is coming... 

FIGURE 17.9 Gradient LC separation of the FAE mixture, stationary phase M N Nucleosil C18, 25 x 0.46 cm i.d., mobile phase gradient of MeOH-H20, flow rate 1 mL/min (reprinted from Pasch et al., 2005, with permission of European Polymer Federation). 

In the carbonylation of MeOH in the presence of Rh-exchanged zeolites, the Rhm ions are reduced to Rh1 ions, which lead to Rh-dicarbonyl and Rh-carbonyl-acetyl complexes.29-32 IrY and RhY zeolites catalyze the carbonylation of MeOH in the presence of a Mel promoter. The kinetics have been determined and IR spectra suggested that with the Ir catalyst the ratedetermining step was the addition of MeOH to the active species followed by migration of a Me coordinated to Ir. With the Rh catalyst, oxidative addition of Mel was the rate-determining step.33 A series of EXAFS measurements was made to determine the structural basis for... 

The reduction steps on active Co sites are strongly affected by activated hydrogen transferred from promoter metal particles (Pt and Ru). Several indications for the existence and importance of hetero-bimetallic centers have been obtained.63 [Cp Co(CO)2] in the presence of PEt3 and Mel catalyzes the carbonylation of methanol with initial rates up to 44 mol L 1 h 1 before decaying to a second catalytic phase with rates of 3 mol L 1 h-1.64 HOAc-AcOMe mixtures were prepared by reaction of MeOH with CO in the presence of Co(II) acetate, iodine, and additional Pt or Pd salts, e.g., [(Ph3P)2PdCl2] at 120-80 °C and 160-250 atm.65... 

Rh(CO)2(acac)(dppp)] catalyst gives rates (100-200 turnovers h 1) and selectivities (80-90%) in the reductive carbonylation of MeOH to acetaldehyde this is comparable to the best Co-based catalysts, but requires a much lower temperature (140 °C) and pressure (70 bar). Addition of Ru to this catalyst results in the in situ hydrogenation of acetaldehyde and production of EtOH.68... 

Poly(7V-vinyl-2-pyrrolidone)-Rh complex was used to catalyze the carbonylation of MeOH to MeOAc and AcOH in supercritical C02 at rates approximately 50% of those in liquid solution, but with minimal catalyst leaching.72... 

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