Butyl alcohol, dehydration

Butanol, reaction over reduced nickel oxide catalysts, 35 357-359 effect of ammonia, 35 343 effect of hydrogen, 35 345 effect of pyridine, 35 344 effect of sodium, 35 342, 351 effect of temperature, 35 339 over nickel-Kieselguhr, 35 348 over supported nickel catalysts, 35 350 Butanone, hydrogenation of, 25 103 Butene, 33 22, 104-128, 131, 135 adsorption on zinc oxide, 22 42-45 by butyl alcohol dehydration, 41 348 chemisorption, 27 285 dehydrogenation, 27 191 isomerization, 27 124, 31 122-123, 32 305-308, 311-313, 41 187, 188 isomerization of, 22 45, 46 isomers... 

Fourier-transform IR spectra show that the main products of butyl alcohol dehydration, when they are adsorbed on HZSM-5 in quantities smaller than or equal to the number of the active sites, are water and butene oligomers, the... 

In summary, for n-, sec-, and isobutyl alcohols there is no diffusion limitation for the dehydration, whereas for the bulkier tert-butyl alcohol, dehydration in channels of HZSM-5 under certain conditions is influenced by diffusion. 

Note that the rate coefficients k determined by our kinetic studies with the static FTIR reactor for all four butyl alcohols are the true rate coefficients for the forward step of stage II of Scheme 1, i. e., k = k+//. But under the steady-state conditions of the flow microreactor, the observed reation rate, Wbuoh, of butyl alcohol dehydration is less than or equal to the product (k+//N) of the rate... 

The poisoning is particularly fast for tert-butyl alcohol dehydration over... 

It is interesting that, for reaction mixtures consisting of molecules with dimensions close to the cross-sections of the catalyst pores (as in the case of butyl alcohol dehydration in HZSM-5), the reacting mixture may be envisaged as a liquid with dimensions less than three. This, in turn, introduces additional factors with respect to the unanalyzed peculiarities of mass-transfer kinetics in the catalyst pores. 

Other separation methods have also led to developments, without necessarily culmi Dating in plant construction. Thus, Hoechst has proposed esterification, or, more precisely, passage through t-butylacetate, and Union Carbide has proposed adsorption on molecular sieves. Butenes isomerization, isobutane dehydrogenation, and c-butyl alcohol dehydration (4i C0 Chemicat) offer complementary methods for synthesizing isobutene. 

In the case of 2 1 layer silicates, Davidtz showed that for butyl alcohol dehydration, the active sites were the tetrahedral and not the octahedral sites, and catalyst activity was observed to be a hnear function of tetrahedral-surface charge-density. 

Ignace and Gates examined t-butyl alcohol dehydration on H-mordenite and calculated that the largest molecules which can pass each other in the pores should possess critical diameters summing > 13 A. 

The latter observation is confirmed by the studies of Gates et al. for various sulphonic acid resins and a number of alcohols. A kinetic study of t-butyl alcohol dehydration in the liquid phase between 35 and 77 °C for the -SO3H form revealed that (i) at low catalyst concentrations the reaction rate was first order in resin concentration and (ii) at high catalyst concentrations the order in resin concentration was four or five. A combined rate expression was written as (equation 5) ... 

The catalytic activity of sulfonic acid resin changes greatly with concentration of sulfo groups. Fig. 3.79 shows the dependence of the rate of /-butyl alcohol dehydration on the resin composition at three temperatures.Here, the acid groups were successively replaced by the salt of one of the alkali metals. The rate at ekch temperature is represented by the following equation. 

You have learned that 2-methyl-2-propanol (fert-butyl alcohol) dehydrates in the presence of acid (Section 9-2). Suggest a synthesis of 1,1-dimethylethyl acetate (tert-butyl acetate, shown in the margin) from acetic acid. Avoid conditions that might dehydrate the alcohol. 

Stepanov AG, Zamaraev KI, Thomas JM. CP/MAS and H NMR study of tert-butyl alcohol dehydration on H-ZSM-5 zeolite. Evidence for the formation of tert-butyl cation and tert-bntyl silyl ether intermediates. Catal Lett 1992 13 407-22. 

Stepanov AG, Sidelnikov VN, Zamaraev KI. In situ C-solid-state NMR and ex situ GC-MS analysis of the products of tert-butyl alcohol dehydration on H-ZSM-5 zeolite catalyst. Chem Eur J 1996 2 157-67. 

Z. W. Qi and K. Sundmacher, Multiple product solutions of tert-butyl alcohol dehydration in reactive distillation, Ind. Eng. Chem. Res. 45, 1613—1621 (2006). 

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