Ethanol Dehydration Reaction Research Articles

Characterization of acid-base catalysts by calorimetric titration: II. Effect of poisoning on titration curves and alcohol dehydration activity

Several commercial aluminas, silica-aluminas and clays have been subjected to poisoning by ammonia and organic bases and subsequently characterized (1) by calorimetry, yielding the heat of adsorption of bases and acids as a function of coverage (2) activity in ethanol and methanol dehydration reactions. A correlation developed in the previous paper [Bakshi, K. R., and Gavalas, G. R., J. Catal. 38, 312 (1975)] describing the activity of fresh catalysts in terms of their acidity and basicity distributions has been used to describe the activity of the poisoned catalysts. Certain rather subtle selectivity changes caused by poisoning have been explained by the corresponding changes in the acidity and basicity distributions.

Langmuir‐hinshelwood kinetics of the dehydration of methanol catalyzed by cation exchange resin

AbstractRates of the dehydration of methanol to dimethyl ether catalyzed by cation exchange resin (polystyrenesulfonic acid) were measured with a differential flow reactor and gas chromatographic analysis. Reaction temperature was 119°C., pressure was 1 atm., and feeds were methanol and mixtures of methanol with argon, dimethyl ether, and water.Rata data for the methanol reaction as well as the previously investigated ethanol dehydration reaction are well represented by Langmuir‐Hinshelwood kinetics with adsorption parameters in the rate equations approximately equal to corresponding values of Langmuir adsorption equilibrium constants estimated from or available in the literature. The reaction model is consistent with previous conclusions regarding mechanism. Its pertinence suggests that at reaction conditions the ion exchange resin offers a nearly homogeneous array of catalytic sites.

Selectivity in the Dehydration and Dehydrogenation Reactions of Ethanol on Copper/Porous Glass Catalyst

多孔性ガラスのみ,フッ化アンモニウムあるいはアルカリ処理および銅を担持した多孔性ガラス触媒などによるエタノールの脱水,脱水紫反応に対する選択性を流通系で研究した鱒その結果はつぎのようである。1)多孔性ガラスのみによるエーテルおよびエチレンの生成はエタノールに関してそれぞれ1/2次と0次となる.2)フッ化アンモニウムあるいは塩化アンモニウムで処理した多孔性ガラスにおける脱水反応の活性はその表面積の低下以上にいちじるしく低下し,その活性は酸性度により支配される.3)銅を担持した多孔性ガラスにおけるエタノールの脱水素反応において,沈殿生成最終pH値は担持された銅の量とその粒子径に影響を与えるが,銅の脱水素活性には影饗をおよぼさない。4)銅を担持するためにアルカリを用いるがその塩基性が強くなると,上澄液のρHが低い領域で脱水活性を低下させる。アルカリとしてアンモニア水を用いると加熱によつて脱水活性を再生する。以上の賭結果から脱水反応には触媒上の酸性点が関係し,隣接2分子吸着によりエーテルが生成し,単独1分子吸藩でエチレンが生成すること,さらに銅を担待する場舎のアルカリの種類により酸性点の被毒に差があるが,銅の脱水素活性には影響をおよぼさないことなどがわかった。

Thermodynamic equilibrium in the vapor phase esterification of Acetic acid with ethanol

AbstractA study of vapor‐phase equilibrium in the reaction system acetic acid‐ethanol–ethyl acetate‐water has been made including an evaluation of past investigations, a calculation of equilibrium constants from thermal data, and new experimental determinations utilizing gas chromatography in a novel method. It was found that the magnitude of the thermodynamic equilibrium constant and its true variation with temperature are appreciably different than previously indicated. This is due to the failure of earlier workers to adequately account for competing reactions, primarily the dehydration of ethanol to ethyl ether. Equilibrium constants were obtained at 100, 120.8, and 170°C. for the ethanol dehydration reaction. Equilibrium positions of the esterification reaction have been determined accurately at the same three temperatures, however the corresponding values of the thermodynamic equilibrium constant remain imperfectly specified because of uncertainty concerning the acetic acid association equilibrium.

Reaction kinetics and adsorption equilibria in the vapor‐phase dehydration of ethanol

AbstractThis work is an experimental assessment of the Langmuir‐Hinshelwood model of heterogeneous catalysis. The vapor‐phase dehydration of ethanol to diethyl ether, as catalyzed by cation exchange resin in the acid form, was the reaction chosen for study.Initial reaction rate data, determined from the integral kinetic data obtained experimentally, allowed selection of the most suitable rate equation from among several plausible equations derived in accordance with the above model. The Langmuir equilibrium adsorption constants in the rate equation were compared with the corresponding constants determined directly from pure component studies in a static adsorption system. The adsorption constants determined for the three reacting components by these independent methods showed definite order‐of‐magnitude agreement. The adsorption studies also provided significant information about the nature of the catalytic site.The extent of agreement in the constants determined by these two independent approaches is considered to be evidence of the theoretical validity of this model. Additional interpretation of the adsorption and kinetic data via this model suggests that the ethanol dehydration reaction proceeds through the reaction of adjacently adsorbed ethanol molecules.