Of dimethyl ether

This compound, which contains atoms arranged tetrahedrally around the boron atom, can readily be isolated from a mixture of dimethyl ether and boron trichloride. On occasions a chlorine atom, in spite of its high election affinity, will donate an electron pair, an example being found in the dimerisation of gaseous monomeric aluminium chloride to give the more stable Al2Clg in which each aluminium has a tetrahedral configuration ... 

Similar activation takes place in the carbonylation of dimethyl ether to methyl acetate in superacidic solution. Whereas acetic acid and acetates are made nearly exclusively using Wilkinson s rhodium catalyst, a sensitive system necessitating carefully controlled conditions and use of large amounts of the expensive rhodium triphenylphosphine complex, ready superacidic carbonylation of dimethyl ether has significant advantages. 

View molecular models of dimethyl ether and ethylene oxide on Learning By Modeling Which one has the greater dipole moment Do the calculated dipole moments bear any relation ship to the observed boiling points (ethylene oxide +10°C dimethyl ether —25°C) d... 

The reaction mechanism and rates of methyl acetate carbonylation are not fully understood. In the nickel-cataly2ed reaction, rate constants for formation of methyl acetate from methanol, formation of dimethyl ether, and carbonylation of dimethyl ether have been reported, as well as their sensitivity to partial pressure of the reactants (32). For the rhodium chloride [10049-07-7] cataly2ed reaction, methyl acetate carbonylation is considered to go through formation of ethyUdene diacetate (33) ... 

Marshall (1986) describes the accident at BASF in Ludwigshafen drawing extensively on original data. On July 28, 1948, a railway tank car suffered a catastrophic failure and discharged its entire contents of 30,400 kg of dimethyl ether. The... 

Compute the energy difference between the anti (left) and syn forms of furfuraldehyde in a solution of dimethyl ether (e=12.0), using either the Onsager (MP2/6-31+G(d)) ortheSCIPCM (B3LYP/6-31+G(d)) SCRF models. The observed energy difference is -0.53 kcal-moT. ... 

The reaction occurs in the liquid phase at relatively low temperatures (about 50°C) in the presence of a solid acid catalyst. Few side reactions occur such as the hydration of isohutene to tertiary hutyl alcohol, and methanol dehydration and formation of dimethyl ether and water. However, only small amounts of these compounds are produced. Figure 5-8 is a simplified flow diagram of the BP Etherol process. 

The decomposition of dimethyl ether (CH3OCH3) to methane, carbon monoxide, and hydrogen gases is found to be first-order At 500°C, a 150.0-mg sample of dimethyl ether is reduced to 43.2 mg after three quarters of an hour. Calculate... 

Fuel industry is of increasing importance because of the rapidly growing energy needs worldwide. Many processes in fuel industry, e.g. fluidized catalytic cracking (FCC) [1], pyrolysis and hydrogenation of heavy oils [2], Fischer-Tropsch (FT) synthesis [3,4], methanol and dimethyl ether (DME) synthesis [5,6], are all carried out in multiphase reactors. The reactors for these processes are very large in scale. Unfortunately, they are complicated in design and their scale-up is very difflcult. Therefore, more and more attention has been paid to this field. The above mentioned chemical reactors, in which we are especially involved like deep catalytic pyrolysis and one-step synthesis of dimethyl ether, are focused on in this paper. 

The external-loop slurry airlift reactor was used in a pilot plant (3000 t/a) for one-step synthesis of dimethyl ether (DME) from syngas. Specially designed internals were used to intensify mass transfer and heat removal. This new technology is highly efficient and easy to scale-up to industrial. 

Direct mass production technique of dimethyl ether from synthesis gas in a circulating slurry bed reactor... 

Quite often, molecules have the same chemical formula but differ in their structures. For example, two compounds have the chemical formula C2 Hg O (Figure 3-2b and c). Dimethyl ether has a C—O—C linkage, while ethanol contains C—O—H. To distinguish between these two different substances, chemists write the formula of dimethyl ether as CH3 OCH3 and the formula of ethanol as CH3 CH2 OH. The first formula indicates that the molecule has two CH3 units linked to an oxygen atom. The second formula tells us that there is a C2 H5 unit attached to an OH group. Molecules that have the same molecular formula but different arrangements of atoms are called isomers. 

C09-0078. Write the Lewis structure of dimethyl ether, (CH3)2 O. Draw a ball-and-stick model of this molecule, showing it as a water molecule with each hydrogen atom replaced by a CH3 group. 

Fig. 2.5. Comparison of energy profile (AG) for pathways to E- and Z-product from the reaction of lithio methyl dimethylphosphonoacetate and acetaldehyde. One molecule of dimethyl ether is coordinated to the lithium ion. Reproduced from J. Org. Chem., 64, 6815 (1999), by permission of the American Chemical Society.

Microwave spectrum, structure, and internal rotation of dimethyl ether. 

Kimura, K., and M. Kubo Structures of dimethyl ether and methyl alcohol. 

Hinshelwood and Askey (6) have investigated the gas phase decomposition of dimethyl ether according to the following reaction. 

Hydrogen bonding accounts for the much higher boiling point (78.5 °C) of ethanol than that of dimethyl ether (-24.9 °C). 

In dimethyl ether, the oxygen atom is sp3 hybridized. In creating two single bonds, each bond is formed by the overlap of one of its sp3 hybrid orbitals with the sp3 hybrid orbital on the adjacent carbon atom. Each of the remaining two hybrid orbitals on the oxygen atom contain a lone pair of electrons. The resulting molecule is polar. The intermolecular forces found operating between molecules of dimethyl ether are therefore dipole-dipole interactions and London forces. 

In a recent publication, Chang and Silvestri have discussed this reaction in detail (109). They reported that under conditions of low (ca. 10%) conversion substantial amounts of dimethyl ether, formed by the reversible dehydration of methanol, are present and 78% of the primary hydrocarbon product consists of C2-C4 olefins. Also, if dimethyl ether, in the absence of water, is used instead of methanol, essentially the same hydrocarbon product distribution is obtained. On the basis of these observations, Chang and Silvestri suggest the reaction path shown below ... 

H NMR monitored reactions of 6 with CH3SO3F in CD2C12 showed the presence of similar quantities of dimethyl ether. 

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