Dimethyl partial oxidation

In an enantiomer-differentiating oxidation at a poly-(L-valine)-coated Pb02 anode, rac-2,2-dimethyl-l -phenyl-1 -propanol was partially oxidized leaving 43% optically pure (5)-alcohol [371]. At a TEMPO-modified graphite felt anode rac-1-phenyl-ethanol has been enantioselectively oxidized in the presence of (-[-sparteine leaving 46% of the (/ [-alcohol with 99.6% ee [372]. However, under the same conditions, an exclusive dehydrogenation of (-[-sparteine to the iminium salt without oxidation of the alcohol was found [373]. 

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. 

Fig. 41. Methanol partial oxidation over M0O3 at 300°C. FA, formaldehyde DME, dimethyl ether. Starting with the approximately stoichiometric oxide, the feed is changed as shown A, 3.6% methanol/helium B, 10% oxygen/helium C, 3.6% methanol/10% oxygen/ helium (after 249).

If this coupling could be realized, combination with Reaction 4 leads to a possible route for the generation of dimethyl ether as a product of partial oxidation of methane (Reaction 24). 

Partial oxidation of methanol has many commerdal appHcahons for the production of formaldehyde, methyl formate and dimethyl ether (dehydration) ... 

Wang and Willey (19) synthesized fine iron oxide particles (FejOs) made out of a solution of iron (Ill)acetylacetonate in methanol and water this solution (no gel was formed at room temperature) was poured into an autoclave and evacuated with respect to the conditions of supercritical methanol. The iron oxide aerogel developed a specific surface area of 10 mVg. The primary particle dimensions were found to be 8-30 nm, as shown by XRD technique. The catalytic test run was the partial oxidation of methanol in the autoclave in the presence of supercritical COj at temperatures varying from 225 up to 325°C and the pressure was 91 bars. The main reaction product formed was dimethyl-ether, small amounts of formaldehyde, and methyl formate with a selectivity below 10% for both minor products. A 20% iron oxide-molybdenum oxide aerogel tested in the same supercritical conditions showed a very good selectivity of 94% for formaldehyde, the other product being only dimethyl-ether. 

The majority of the oxides tested totally combusted methanol below 400°C. Over the oxide Sb203, methanol showed exceptional stability, as only 3% was converted at 500°C, whereas the oxides M0O3, Nb20s, Ta20s, and WO3 did not readily combust methanol. However, methanol conversion was high and major reaction products were formaldehyde and dimethyl ether, which are desirable byproducts from a methane partial oxidation process. 

Lampert presented a catalytic partial oxidation technique for sulfur compounds that was developed by the former Engelhard (now BASF) corporation [296]. The sulfur compounds of natural gas or liquefied petroleum gas were converted into sulfur oxides at a low 0/C ratio of 0.03 in a ceramic monolith over a precious metal catalyst. These sulfur oxides were then adsorbed downstream by a fixed adsorber bed, which contained adsorption material specific to sulfur trioxide and sulfur dioxide, which could trap up to 6.7 g sulfur per 100 g adsorbent. The partial oxidation was performed at a 250 °C monolith inlet temperature, the adiabatic temperature rise in the monolith amounted to 20 K. Light sulfur compounds usually present in natural gas and liquefied petroleum gas, such as carbon oxide sulfide, ethylmercaptane, dimethyl sulfide and methylethyl sulfide, could be removed to well below the 1 ppm level. Exposure of the monolith to an air rich fuel/air mixture at temperatures exceeding 150 °C had to be avoided. The same applied for contact with fuel in the absence of air regardless of the temperature. 

Selectivity of methanol partial oxidation with O2 in SCCO2 at 200-300°C, using iron-based aerogels can be shifted towards either dimethyl ether (70%), formaldehyde or methyl formate as the predominant products depending on the reaction conditions and catalyst. Though methanol conversion was lower than in the gas-phase process, the production of desired ether, aldehyde and ester in the SCF process is higher. 

Partially oxidized methylsiloxane polymer. May be diluted with dimethyl siloxane polymer and dispersed in benzene Silica aerogel, presumably rendered hydrophobic by reaction in situ with the siloxane As claimed 7.5... 

Carbonyl sulfide and carbon disulfide pass more or less intact through the Stretford absorber, while about half of the thiophene is typically removed. Methylmercaptan is largely oxidized to dimethyl disulfide, DMDS, which is largely incorporated into the sulfur cake. Higher mercaptans are partially oxidized to disulfide, but most are released to the atmosphere in the oxidizer, in some cases causing severe odor problems, which may require incineration of the oxidizer vent stream. 

Finally, for the production of chemicals, ceria-based catalysts have been applied to processes such as the conversion of syngas into alcohols, C C coupling reactions, partial oxidation reactions, direct synthesis of dimethyl carbonate, esterification, reactions involving aldolic condensations and selective hydrogenation. " ... 

Mix, K.H., and H.Gg.Wagner (1983), Rate constants of reactions of partially oxidized hydrocarbons with oxygen atoms in the gas phase. Part II Reactions of dimethyl ether, diethyl ether, and acetone, Oxid. Commun., 5, 321-329. 

The sulfonation of PPO was done using chlorosulfonic acid. SPPO with an lEC value of 1.3 to 2.5 was prepared by chlorosulfonation of 2,6-dimethyl polyphenylene oxide in chloroform solvent. Modified SPPO polymer (SP3O) (R.M. Dempsey and A.B. LaConti, USA/MERDC Contract No. DAAK02-73-C-0407, 1974) was also prepared by partial bromonation and subsequent sulfonation of 2,6 diphenyl polyphenylene oxide. The lEC values of the modified SPPO were in the range of 1.3 to 1.5. Polymers were vacuum dried for 72 hours and dissolved in solvent mixtures. The casting solution concentrations were 6 to 7 % polymer in CHCls/alcohol or CH3N02/alcohol mixtures when porous polypropylene and polysulfone membranes, respectively, were used as the substrate membranes. 

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