Decomposition Of Diethyl Ether Research Articles

Fine‐Tuning Texture of Highly Acidic HZSM‐5 Zeolite for Efficient Ethanol Dehydration

AbstractAchieving high and stable ethylene yield from (bio)ethanol dehydration over highly active acidic zeolite remains challenging due to undesired side‐reactions. To overcome this issue, the fine‐tuned textural property of the HZSM‐5 catalyst with a hierarchical structure is crucial to overcome diffusion restrictions and limit undesired side‐reactions. Herein, the texture of high acid catalysts obtained via hydrothermal synthesis was simply tuned in the presence of tetrabutylammonium hydroxide as a meso‐ and micropore directing agent and the controlled molar ratio of NaF‐to‐Al2O3. The hierarchically designed HZSM‐5 with the small nanosheet size of 6.5 nm exhibits a high external surface area and mesopores, largely enhancing the catalytic performance of ethanol dehydration up to 95 % ethylene yield as well as preventing the formation of heavy hydrocarbons. To gain insights into the mechanistic points of view, the in situ DRIFTS study revealed that ethylene could form through ethoxy‐mediated mechanism or decomposition of diethyl ether (DEE). The catalyst deactivation caused by polyaromatics obtained from side‐reactions is the reason for low ethanol conversion and high DEE selectivity. Reducing the crystal size of highly acidic zeolite to ultra‐thin nanosheet can shorten the residence time of ethanol, intermediates, and products in porous structures, substantially suppressing the transformation of coke precursors into heavy hydrocarbons to achieve high and stable ethylene yield.

Conjugated decomposition of ethers during the reaction of nitroacetic acid with epichlorohydrin

1. Nitroacetic acid reacts with epichlorohydrin under mild conditions to give 1-chloro-2-hydroxy-propyl nitroacetate and the products of the further addition of epichlorohydrin. 2. In the presence of diethyl ether, together with 1-chloro-2-hydroxypropyl nitroacetate, are found ethyl nitroacetate and 1-chloro-3-ethoxy-2-propanol. 3. A scheme was proposed for the conjugated decomposition of diethyl ether during the reaction of nitroacetic acid with epichlorohydrin.

The thermal decomposition of diethyl ether. IV. Production of cyanides and the mechanism of the nitric-oxide-induced reaction

The formation of cyanides in the nitric-oxide-induced decomposition of diethyl ether has been determined as a function of nitric oxide pressure. A possible chain mechanism for nitric oxide consumption and cyanide production is considered.

The thermal decomposition of diethyl ether. II. Analytical survey of the reaction products as a function of reaction conditions

By mass-spectrometric analysis combined with vapour-phase chromatography the reaction products from the thermal decomposition of ether have been determined at various stages of the reaction (uninhibited and inhibited by nitric oxide) for initial ether pressures of 80 to 1000 mm. The effects of added hydrogen and of carbon tetrafluoride on the composition of the products have also been examined. No major changes in the chemistry of the reaction occur with these variations in conditions. Factors are given for calculating true rate constants from pressure changes accompanying the reaction. Corrected values of rate constants vary with the conditions in the same way as the values derived from uncorrected pressure changes, the correspondence being close for the uninhibited reaction.

The thermal decomposition of diethyl ether. III. The action of inhibitors and the mechanism of the reaction

Small quantities of nitric oxide reduce the rate of thermal decomposition of diethyl ether at 525 °C to about one-quarter. Much larger amounts accelerate the decomposition, but the concentration ranges in which the ‘ maximally inhibited ’ reaction and the ‘ nitric-oxide-induced’ reaction can be studied are so widely separated that these reactions can be treated as two distinct entities. The ‘uninhibited’ reaction constitutes a third. Reaction products and kinetics are recorded for all three, and nitric oxide consumption is measured for the first two. In all three the major products are the same, with secondary differences which are discussed. In the presence of nitric oxide small amounts of cyanides and other compounds are formed. In the nitric-oxide-induced reaction 1.4 molecules of ether are decomposed for each molecule of nitric oxide used up: in the maximally inhibited reaction the ratio, which is dependent on the ether pressure, is very much greater. The rate of the maximally inhibited reaction is independent of the concentration of nitric oxide, or of propylene, and the same for the two inhibitors (as is now proved by direct analysis). The first-order rate constant varies with the initial pressure of ether according to the equation k inhib. = ( A [ether])/(1 + B [ether]) + C [ether]. The rate constant of the uninhibited reaction varies with ether pressure according to an expression which, although probably of different algebraical form, is empirically similar to the above over a considerable range. The nitric-oxide-induced reaction is nearly of the first order with respect both to ether pressure and to nitric oxide pressure. The maximally inhibited reaction is shown to be most probably a molecular decomposition of the ether. The uninhibited reaction is predominantly a chain reaction, the mechanism of which is discussed. The nitric-oxide-induced reaction, it is suggested on the basis of the experimental evidence, is largely initiated by a generation of radicals in an attack of nitric oxide on ether. It is possibly also in part a molecular decomposition of ether caused by collision with nitric oxide.

The thermal decomposition of diethyl ether. I. Rate-pressure relations

In the thermal decomposition of diethyl ether the first-order rate constant ( k ) varies with the pressure ( p ) of the ether itself, or that of added hydrogen, or that of various chemically inert gases according to a more complex pattern than has hitherto been supposed. In general, k increases approximately linearly with p X over a certain range: the slope of the curve then decreases as though a limit were being approached. When X refers to ether, hydrogen or certain other gases no limit is in fact reached, but k continues to increase at a considerably reduced rate. With certain gases, however, the slope of the curve becomes very small or zero. Changes in k are not explicable by variations in the chemical composition of the products. The forms of the k-p curves are qualitatively similar for the uninhibited reaction (largely a chain process) and for the nitric oxide-inhibited reaction (hypothetical molecular reaction), but the effects are quantitatively quite different. The k-p relations for the molecular reaction conform to those recently established for the decomposition of paraffins and of nitrous oxide, and may possibly be interpreted by the extended theory of unimolecular reactions proposed for these examples. The relations for the chain reactions are more complicated but the interpretation probably includes considerations similar to the above, applied to the initial molecular process by which the chains start.

Catalysis and inhibition of a homogeneous gas reaction the influence of nitric oxide on the decomposition of diethyl ether

A fair number of examples of homogeneous catalysis of gaseous reactions are now known, but no comprehensive generalizations about them are yet possible, except perhaps that the catalyst always permits a reaction with a lower activation energy and a simpler activation mechanism to replace the normal reaction. Nitric oxide is known to catalyse the decomposition of nitrous oxide, of acetaldehyde and of chloral, and the experiments to be described were begun with the object of investigating systematically which types of reaction are subject to the influence of this catalyst. Certain regularities have been observed in the types of organic decomposition reaction which are catalysed by iodine. Diethyl ether, for example, reacts as follows: C 2 H 5 . O. C 2 H 5 → C 2 H 6 + CH 3 CHO → C 2 H 6 + CH 4 + CO, (1) and the first experiments were made to see whether nitric oxide would provoke an analogous reaction.

The Kinetics of the Decomposition of Ethyl Ether at High Pressures

The decomposition of diethyl ether has been investigated with considerable accuracy at pressures up to 260 atmospheres at 426°C. The results confirm the previous approximate values found by Steacie and Solomon. The rate of the reaction is still increasing at the highest pressures investigated. The results may be qualitatively explained by the Rice-Herzfeld mechanism, and support the idea that the reaction is not a simple unimolecular change.

The Decomposition of Diethyl Ether in Contact with Platinum and Tungsten

The Decomposition of Diethyl Ether in Contact with Platinum and Tungsten

Quasi-unimolecular reactions. The decomposition of diethyl ether in the gaseous state

During the last few years we have made in Oxford an investigation of a number of gaseous reactions with the chief object of applying the principles of the kinetic theory and discovering the mechanism of “activation.” In order to make clear the bearing of the fresh experiments described in this paper it will be convenient first to give a brief summary of the general development of the enquiry