Methyl formate powder

Figure 4. Correlation of the chemical shielding and C—H dipolar coupling tensors of the formate group of 50% C-enriched methyl formate powder, a. Computer calculated 2D spectrum for a = 33° and p = 85°. b, Experimental spectrum recorded at 25-MHz C resonance and 90 K. The 2D spectrum permits the determination of the relative orientation of two molecular interaction tensors without the need of growing single crystals. (Reproduced, with permis n, from Ref.

Using the mercuric acetate oxidation-zinc powder reduction method, 277 and methyl ( )-geissoschizoate (276) were obtained in about a 3 1 ratio. Formyla-tion of 276 with methyl formate in the presence of lithium diisopropylamide yielded ( )-geissoschizine as the sole product (156). 

Aromatic aldehydes (10 mmol) and trimethylorthoformate (20 mmol) was added to a mixture of sulfonamide (10 mmol), finely powdered calcium carbonate (9 g) and K-10 clay (2 g). The solid homogenized mixture was placed in a modified reaction tube which was connected to a removable cold finger and sample collector to trap the ensuing methanol and methyl formate. The reaction tube is inserted into Maxidigest MX 350 (Prolabo) microwave reactor equipped with a rotational mixing system. After irradiation for a specified period, the contents were cooled to room temperature and mixed thoroughly with ethyl acetate (2 x 20 mL). The solid inorganic material was filtered off and solvent was evaporated to afford tlie residue which was crystallized from the mixture of hexane and ethyl acetate. 

A mixture of 3,3-diethoxypropanenitrile (1.98 mol) and methyl formate (2.48 mol) in 1100 ml THF at 10°C was treated with 1.0 M potassium /-buloxidc in THF (2.2 mol) over 45 minutes and the slurry stirred 2 hours at ambient temperature. The mixture was diluted with 400 ml hexane and stirred an additional 20 minutes and was then fdtered. The fdter cake was washed with hexanes/THF, 1 1, then dried, and the product isolated in 73.0% as a pale tan powder. 

Early studies on titania powders showed that methanol generated methyl formate as the principle photooxidation product. Molybdena- and vanadia-modified Ti02 catalysts demonstrated at least an eighty percent drop in activity relative to pure titania, although selectivity to dimethoxymethane (and thus suppression of further oxidation products) was almost total [87]. 

Thus, the formation of the organoperoxide transition state is dependent on the availability of the peroxide radical formed by photoexcitation of adsorbed oxygen, the rate limiting step of the process [88], Methyl formate photodecomposition has also been studied on titanium dioxide powders. In the presence of oxygen, methyl formate decomposed to form CO, CO2, formaldehyde, and water [90]. 

Methanol dehydrogenates to methyl formate over fresh WC and P-W2C powders with selectivities higher than 90% (109,110). The dominant side reaction is the decomposition to synthesis gas. Over WC and P-W2C modified with oxygen, methanol selectively dehydrates to dimethylether at 473 K and at higher reaction temperatures, C2-C4 olefins are produced (47). Thus, the dehydrodimerization of methanol apparently requires WC sites. These sites are titrated by chemisorbed oxygen. Thus, oxygen on the surface inhibits the formation of methyl formate and introduces a surface acid function WO that catalyzes dehydration by carbenium-ion type catalysis. 

Typical specifications of the powder are as follows sodium methylate, 97.5% sodium hydroxide, 0.5% sodium carbonate, 0.4% sodium formate, 0.3% and free methanol, 0.5%. 

The photo-Kolbe reaction is the decarboxylation of carboxylic acids at tow voltage under irradiation at semiconductor anodes (TiO ), that are partially doped with metals, e.g. platinum [343, 344]. On semiconductor powders the dominant product is a hydrocarbon by substitution of the carboxylate group for hydrogen (Eq. 41), whereas on an n-TiOj single crystal in the oxidation of acetic acid the formation of ethane besides methane could be observed [345, 346]. Dependent on the kind of semiconductor, the adsorbed metal, and the pH of the solution the extent of alkyl coupling versus reduction to the hydrocarbon can be controlled to some extent [346]. The intermediacy of alkyl radicals has been demonstrated by ESR-spectroscopy [347], that of the alkyl anion by deuterium incorporation [344]. With vicinal diacids the mono- or bisdecarboxylation can be controlled by the light flux [348]. Adipic acid yielded butane [349] with levulinic acid the products of decarboxylation, methyl ethyl-... 

Additional hypotheses concerning prostaglandin biosynthesis in P. homomalla resulted from isolation of 11R-HETE (76) from the polar lipid fraction [95]. Apparently, 11R-HETE (76) is also a minor product of incubations of arachidonic acid with acetone powder preparations of P. homomalla [95], In this alternate hypothesis (Scheme 8), an 11-hydroxy or 11-hydroperoxy-8,9-allene oxide intermediate is formed from a sequence of oxidations at C8 and Cll. Opening of the allene oxide to a transient C8 earboeation induces eycli-zation with a consequent addition of water to C15. This proposed pathway leads initially to formation of PGE2 (16 or 38), which following acetylation, elimination of acetic acid from Cl 1-12, and esterification, forms the observed major natural product in the coral, 15-acetoxy methyl PGA2 (36 or 54). Notably, if... 

Although there are many variations on how carbon fibers are made, the typical process starts with the formation of PAN fibers from a conventional suspension or solution polymerization process between a mixture of acrylonitrile plastic powder with another plastic, such as methyl acrylate or methyl methacrylate, and a catalyst. The product is then spun into fibers, with the use of different methods, in order to be able to achieve the internal atomic structure of the fiber. After this, the fibers are washed and stretched to the desired fiber diameter. This step is sometimes called "spinning" and is also vital in order to align the molecules inside the fiber and thus provide a good basis for the formation of firmly bonded carbon crystals after carbonization [7]. 

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