Oxidation products dimethyl ether

The oxidation of dimethyl ether, a process devdoped by the Japanese company Akita Petrochemicals, is similar to the foregoing techniques. It is based on the oxidation of dimethyl ether, which is a by-product methanol 3mtheas in the high-pressure pro-... 

Wang and Willey (260) report the oxidation of methanol in SCCO2 over pure and mixed oxide (Fe, Si, and Mo) aerogel catalysts. Selective oxidation products of dimethyl ether, methyl formate, and formaldehyde were found from 200°C to 300°C, and the selectivity depended on the catalyst used. Pure iron oxide favored dimethyl ether (80% yield), low levels of iron oxide on silica favored... 

Tetrafluoroethylene Oxide TFEO has only been prepared by a process employing oxygen or ozone because of its extreme reactivity with ionic reagents. This reactivity may best be illustrated by its low temperature reaction with the weak nucleophile, dimethyl ether, to give either of two products (47) (eq. 10). 

SuIfona.tlon, Sulfonation is a common reaction with dialkyl sulfates, either by slow decomposition on heating with the release of SO or by attack at the sulfur end of the O—S bond (63). Reaction products are usually the dimethyl ether, methanol, sulfonic acid, and methyl sulfonates, corresponding to both routes. Reactive aromatics are commonly those with higher reactivity to electrophilic substitution at temperatures > 100° C. Tn phenylamine, diphenylmethylamine, anisole, and diphenyl ether exhibit ring sulfonation at 150—160°C, 140°C, 155—160°C, and 180—190°C, respectively, but diphenyl ketone and benzyl methyl ether do not react up to 190°C. Diphenyl amine methylates and then sulfonates. Catalysis of sulfonation of anthraquinone by dimethyl sulfate occurs with thaHium(III) oxide or mercury(II) oxide at 170°C. Alkyl interchange also gives sulfation. 

Pellotine and Anhalonidine. The A -acetyl derivative of mezcaline (I NHj— NHAc), on treatment with phosphoric oxide, yields 6 7 8-trimethoxy-l-methyl-3 4-dihydrowoquinoline (picrate, m.p. 181-2°), which, on successive catalytic hydrogenation and treatment with methyl sulphate, yields 6 7 8-trimethoxy-l 2-dimethyl-l 2 3 4-tetrahydro-isoquinoline identical with 0-methylpellotine (picrate, m.p. 167-8°), whence it appears that pellotine must be a dimethyl ether of 6 7 8-trihydroxy-1 2-dimethyl-l 2 3 4-tetrahydrowoquinoline. Pellotine and anhalonidine on complete methylation yield the same product, and as anahalonidine is a secondary base and differs from pellotine by containing —CHj less, it must be a dimethyl ether of 6 7 8-trihydroxy-l-methyl-1 2 3 4-tetrahydrowoquinoline, and pellotine should be A -methyl-anahalonidine. 

In the first of these, the key step in the synthetic sequence involves an oxidative phenol coupling reaction patterned after the biosynthesis of the natural product. Preparation of the moiety that is to become the aromatic ring starts by methyla-tion of phloroglucinol (5) with methanolic hydrogen chloride to give the dimethyl ether (6). Treatment of that intermediate with sulfuryl chloride introduces the chlorine atom needed in the final product (7). 

DMC and EG were main products of the transesterification reaction. No by-product such as dimethyl ether and glycol monoethyl ether was observed in the resulting products. Only small peaks of ethylene oxide from the decomposition of EC could be detected at longer reaction time and at high temperature. 

Depending on the reason for converting the produced gas from biomass gasification into synthesis gas, for applications requiring different H2/CO ratios, the reformed gas may be ducted to the water-gas shift (WGS, Reaction 4) and preferential oxidation (PROX, Reaction 5) unit to obtain the H2 purity required for fuel cells, or directly to applications requiring a H2/CO ratio close to 2, i.e., the production of dimethyl ether (DME), methanol, Fischer-Tropsch (F-T) Diesel (Reaction 6) (Fig. 7.6). 

Anodic addition converts enolacetates into a-acetoxyketones or enones, depending on the reaction conditions [135], conjugated dienes into 1,2- or 1,4-dimethoxy alkenes [65], and hydroquinone dimethyl ethers into quinone bisketals [136, 137]. Anodic addition also affords products, some of which are of industrial interest, such as propylene oxide [138a] or 1,4-dimethoxydihydrofuran [138b]. To... 

One of the major advantages of the metal oxide catalyst over that of the straight metal catalyst is the elimination of the need for a methanol recovery tower. The metal oxide catalysts result in not only high yields, but also very high conversion rates. Consequently, there is no need to recover the small amounts of methanol that remain unreacted. It becomes part of the aqueous formaldehyde solution and serves as a stabilizer for the system. By-products are CO, CO2, dimethyl ether, and formic acid. The process yields (the percent of the methanol that ends up in formaldehyde) are 95-98%. 

The reactivity ot the titania supported vanadium oxide catalysts was probed by the methanol oxidation reaction. The oxidation ot methanol over the titania supported vanadia catalysts exclusively yielded tormaldehyde, 95%+, as the reaction product. The titania support in the absence ot surtace vanadia yielded dimethyl ether and trace amounts ot CO2 The almost... 

Dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid were shown to form after the red pigment stage that occurred during the conversion of DOPA into a melanin, by Raper, who isolated these compounds as their dimethyl ethers.72 The presence of 5,6-dihydroxyindoles in solutions of DOPA, dopamine, and noradrenaline which are undergoing oxidation has subsequently been confirmed by paper and thin-layer chromatography.118,120,222 5,6-Dihydroxyin-dole and 5,6-dihydroxyindole-2-carboxylic acid have recently been isolated from the alkali fusion products of sepiomelanin, indicating... 

The results of catalytic partial oxidation of methanol over the spinel catalysts derived from CoAl- and CoAISn-LDH are presented in Table 2. A methanol conversion of 30 to 50 mol % was obtained over catalyst derived from CoAI-LDH. The products obtained were H2, H20, CO and C02. Other products such as formaldehyde, methyl formate or dimethyl ether was not observed under the present experimental conditions. The selectivity of H20 was very high (= 40 to 60 %), probably because of the involvement of the complete oxidation of methanol over these catalysts. It is interesting to note from the Table that the methanol conversion rate and the selectivity of CO2 increased over the catalyst derived from the Sn-containing analogue. The observation that only traces of CO is produced in the Sn-containing catalyst, is attractive for the development of catalyst for POM reaction to produce H2 for fuel cell applications. The only inconvenience is the higher selectivity of H2O by complete oxidation, probably because of the higher Co content in the sample. 

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