Formaldehyde-formic acid methylations with

In similar manner 20a-acetylamino-18-acetoxy-3 8-aminopregn-5-ene (LXXXVI) was prepared (74) which on formaldehyde-formic acid methylation afforded the 3 8-dimethylamino derivative LXXXVII. Treatment of this base with cyanogen bromide, followed by alkaline hydrolysis, afforded 3-X-methylholarrhimine LXXV (mp 160°-163° [a]i) —17° in chloroform). Although both isomeric bases show a close resemblance in physical constants, the respective IR-spectra differ fundamentally, and their comparison with natural monomethylholarrhimine II showed identity of the latter alkaloid with 3-iV-methyl-holarrhimine (LXXV). By exclusion, the monomethylholarrhimine I has to be formulated as 20-A-methylholarrhimine (LXXVI). 

The mechanism of methanol oxidation on Pt-based catalysts has been studied for several decades [1-14]. Complex parallel and series reaction pathways in which several adsorbed species and soluble intermediates were involved in methanol oxidation were proposed by Bagotzky et al. [2]. The in situ application of infrared spectroscopy during methanol oxidation showed that adsorbed CO is formed on the Pt surface [15]. However, other adsorbed intermediates are still not identified. Formaldehyde, formic acid, methyl formate, and dimethoxy methane have been identified as soluble intermediates [8, 10, 16-18]. The quantitative analysis of methanol oxidation products changing with various parameters can help us better understand the mechanism of methanol oxidation and identify reactirai pathways. This can be achieved by online quantitative differential electrochemical mass spectrometry (OEMS), which will be discussed in Sect. 3. 

The Formaldehyde-Formic Acid Method, This method applies to primary and secondary amines, which when boiled with a formalin-formic acid mixture undergo complete methylation to the corresponding tertiary amine. This method has the advantage over the dimethyl sulphate method in that quaternary salts clearly cannot be formed. 

The conventional electrochemical reduction of carbon dioxide tends to give formic acid as the major product, which can be obtained with a 90% current efficiency using, for example, indium, tin, or mercury cathodes. Being able to convert CO2 initially to formates or formaldehyde is in itself significant. In our direct oxidation liquid feed fuel cell, varied oxygenates such as formaldehyde, formic acid and methyl formate, dimethoxymethane, trimethoxymethane, trioxane, and dimethyl carbonate are all useful fuels. At the same time, they can also be readily reduced further to methyl alcohol by varied chemical or enzymatic processes. 

Formaldehyde is a gas with a boiling point of -21 °C. It is usually supplied as a stabilised aqueous solution ( 40% formaldehyde) known as formalin. When formalin is used as the source of the aldehyde, impurities present generally include water, methanol, formic acid, methylal, methyl formate and carbon dioxide. The first three of these impurities interfere with polymerisation reactions and need to be removed as much as possible. In commercial polymerisation the low polymers trioxane and paraformaldehyde are convenient sources of formaldehyde since they can be obtained in a greater state of purity. 

The methylation of secondary amines works better than for primary amines because there is no competition between the formation of mono- or dimethylated products. The best results for the microwave-enhanced conditions were obtained when the molar ratios of substrate/formaldehyde/formic acid were 1 1 1, so that the amount of radioactive waste produced is minimal. The reaction can be carried out in neat form if the substrate is reasonably miscible with formic acid/aldehyde or in DM SO solution if not. Again the reaction is rapid - it is complete within 2 min at 120 W microwave irradiation compared to longer than 4 h under reflux. The reaction mechanism and source of label is ascertained by alternatively labeling the formaldehyde and formic acid with deuterium. The results indicate that formaldehyde contri-... 

In the reactions of the N-unsubstituted parent amino alcohols 27 and 29 with a formaldehyde/formic acid mixture, ring closure and N-methylation... 

Formic acid, methyl formate, and CO were detected when photoreduction was performed in Ti silicalite molecular sieve using methanol as electron donor.173 Mechanistic studies with labeled compounds indicated, however, that CO originates from secondary photolysis of formic acid, whereas methyl formate emerges mainly from the Tishchenko reaction of formaldehyde, the initial oxidation product of methanol. 

TheN-monomethylandtheN,N-dimethylhomologuesof2C-Dhavebeen synthesized from 2C-D. The N-monomethyl compound was obtained by the quatemization of the Schiff s base formed between 2C-D and benzaldehyde with methyl sulfate, followed by hydrolysis the hydrochloride salt had a melting point of 150-151 °C,fromEtOH. The N,N-dimethyl compound resulted from the action of formaldehyde-formic acid on 2C-D the hydrochloride salt had a melting point of 168-169 °C from EtOH/ether. These two compounds were some ten times less effective in interfering with conditioned responses in experimental rats. There is no report of their having been explored in man. 

Capello et al.16 applied LCA to 26 organic solvents (acetic acid, acetone, acetonitrile, butanol, butyl acetate, cyclohexane, cyclohexanone, diethyl ether, dioxane, dimethylformamide, ethanol, ethyl acetate, ethyl benzene, formaldehyde, formic acid, heptane, hexane, methyl ethyl ketone, methanol, methyl acetate, pentane, n- and isopropanol, tetrahydrofuran, toluene, and xylene). They applied the EHS Excel Tool36 to identify potential hazards resulting from the application of these substances. It was used to assess these compounds with respect to nine effect categories release potential, fire/explosion, reaction/decomposition, acute toxicity, irritation, chronic toxicity, persistency, air hazard, and water hazard. For each effect category, an index between zero and one was calculated, resulting in an overall score between zero and nine for each chemical. Figure 18.12 shows the life cycle model used by Capello et al.16... 

Alternatively, the base XLIII was methylated with formaldehyde-formic acid to yield the ditertiary base XLIV which on Hofmann degradation yielded a mixture of tetramethyldihydroholarrhimine... 

The synthesis of cyclobuxoxazine-C was accomplished starting from dihydrocyclomicrophylline-F (CCCXXXVIII). On treatment with three equivalents of formaldehyde in dioxane solution, this base yielded (via an intermediary azomethine) the methyl ether CCCXLI which, on filtration in methylene chloride solution through a column of alumina, cyclized to cyclobuxoxazine-C. A similar cyclization was also observed on attempted methylation of dihydrocyclomicrophylline-F with formaldehyde-formic acid which gave rise to cyclobuxoxazine-A (212). 

Himbeline was readily identified as A -demethylhimbacine since methylation with formaldehyde-formic acid gave himbacine (2). The alkaloid was further characterized by its acetyl and methane sulfonyl derivatives rather surprisingly these derivatives could not be hydrolyzed under the usual conditions. In contrast to this unreactivity the double bond of himbeline was easily hydrogenated, readily suffered oxidation by permanganate to yield the lactone acid XVII, and was attacked by performic acid to give the epoxide and glycol. No explanations of these abnormal reactivities have been advanced. 

Oxidation of methanol in the liquid phase is slow. At 81—145° C with azodi-isobutyronitrile and t-butyl peroxide as initiators, the oxidation products are formaldehyde, formic acid, hydrogen peroxide, and methyl formate [2]. 

The main problems regarding the replacement of batteries by direct alcohol fuel cells are related to the largest volume required by the fuel cells, as compared to the batteries which have become highly compact (because DAFCs have not reached yet high efficiencies), elimination of residues of the methanol partial oxidation (generally mixtures of water with formic acid, methyl formate, and formaldehyde), and the high temperature which can reach the DAFC (up to around 85 °C for cells using Nafion membranes) [11, 12]. 

In general, acetic acid production via acetaldehyde oxidation takes place continuously in a bubble column at 50-80 °C with pressures of 1-10 bar. The construction material of choice for the reactor is austenitic Cr-Ni-steel. The acetic acid product serves as process solvent and the concentration of acetaldehyde is kept at 3%. It is necessary to keep the temperature over 50 °C to obtain a sufficient peroxide decomposition and oxidation rate. To remove the heat of the exothermic reaction, the reaction mixture is circulated through an external heat exchanger. Accurate temperature control is important to decrease oxidative degradation of acetic acid to formic acid, CO2, and water. The reaction mixture is separated by several distillation units. The process yields are typically in the range of 90-97% and the purity of acetic acid is higher than 99%. Typical by-products are CO2, formic acid, methyl acetate, methanol, methyl formate, and formaldehyde. 

For preparation of A -methylaniline, an important commodity, industrial methods of reductive methylation by the mixture formaldehyde/formic acid, catalytic alkylation with methanol, reductive methylation of nitrobenezene or catalytic arylation of methylamine by phenol have been developed. Producers use various technologies depending on the range of the related products they offer to the market. 

In [47], along with gaseous ethane, various condensable products, such as methyl formate, formaldehyde, formic acid, and acetic acid, were observed. 

Anhydrous, monomeric formaldehyde is not available commercially. The pure, dry gas is relatively stable at 80—100°C but slowly polymerizes at lower temperatures. Traces of polar impurities such as acids, alkahes, and water greatly accelerate the polymerization. When Hquid formaldehyde is warmed to room temperature in a sealed ampul, it polymerizes rapidly with evolution of heat (63 kj /mol or 15.05 kcal/mol). Uncatalyzed decomposition is very slow below 300°C extrapolation of kinetic data (32) to 400°C indicates that the rate of decomposition is ca 0.44%/min at 101 kPa (1 atm). The main products ate CO and H2. Metals such as platinum (33), copper (34), and chromia and alumina (35) also catalyze the formation of methanol, methyl formate, formic acid, carbon dioxide, and methane. Trace levels of formaldehyde found in urban atmospheres are readily photo-oxidized to carbon dioxide the half-life ranges from 35—50 minutes (36). 

Between 50 and 60% of the formaldehyde is formed by the exothermic reaction (eq. 23) and the remainder by endothermic reaction (eq. 24) with the net result of a reaction exotherm. Carbon monoxide and dioxide, methyl formate, and formic acid are by-products. In addition, there are also physical losses, hquid-phase reactions, and small quantities of methanol in the product, resulting in an overall plant yield of 86—90% (based on methanol). 

A. Ethyl N- p-tolylsulfonylmethyl)carhamate,[Carbamic acid, (4 -methyl-phenylsulfonylmethyl)-, ethyl ester]. A solution of 178 g. (1.0 mole) of sodium p-toluenesulfinate (Note 1) in 1 1. of water is placed in a 3-1., three-necked daak, equipped with a condenser, an efficient mechanical stirrer, and a thermometer. After addition of 100 ml. (108 g.) of a 34—37% solution of formaldehyde ca. 1.2-1.4 moles) (Note 2), 107 g. (1.2 moles) of ethyl carbamate (Note 3), and 250 ml. of formic acid (Note 4), the stirred solution is heated to 70°. Soon after this temperature is reached, the reaction mixture becomes turbid by separation of the... 

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