Formaldehyde, and methylation

Fire Hazards - Flash Point (deg. F) 203 OC Flammable limits in Air (%) 3 - 6.3 Fire Extinguishing Agents Water, foam, dry chemical, or carbon dioxide Fire Extinguishing Agems Not to be Used Not pertinent Special Hazards of Combustion Products Sulfur dioxide, formaldehyde, and methyl mercaptan may form Behavior in Fire Not pertinent Ignition Temperature (deg. F) 572 Electrical Hazard Not pertinent Burning Rate 2.0 mm/min. 

Spath and Kruta have also prepared dZ-tetrahydropalmatine by the process described for meso- and r-corydalines (p. 289), and by condensing tetrahydropapaveroline with formaldehyde and methylating the product, obtained in poor yield, a mixture of tetrahydropalmatine and ftorcoralydine. 

Methanol is a major bulk chemical, and its global annual production exceeds 37 million tons. It is mainly used for the production of formaldehyde and methyl 6butyl ether (MTBE). Especially, formaldehyde is dominantly used for producing resins. At present, methanol and its decomposed derivatives can be oxidized to CO2 and H2O by the proper selection of supported noble metal catalysts such as palladium, platinum, and gold. 

Once methanol is produced, it can be converted to an extensive range of materials. The following reactions illustrate some of the chemicals of major importance that can be made from methanol. Among these are dimethyl ether, acetic acid, methyl acetate, acetic anhydride, vinyl acetate, formaldehyde, and methyl tertiarybutyl ether (MTBE). 

CASRN 75-18-3 molecular formula C2H0S FW 62.14 Photolytic. Sunlight irradiation of a mixture of methyl sulfide (initial concentrations 0.2-2.5 ppm) and oxides of nitrogen (86-580 ppb) in an outdoor chamber at various time intervals (2-7 h) yielded nitrogen dioxide, ozone, sulfur dioxide, nitric acid, formaldehyde, and methyl nitrate, a sulfate aerosol, and methane sulfonic acid (Grosjean, 1984a). 

In dry acetonitiile/sodium perchlorate, however, sodium methanesulfonate and CO is obtained. A methylthiomethyl cation 159, (Eq. (220) ), is believed to be an intermediate, which is hydrolyzed to formaldehyde and methyl mercaptane. Both products are subsequently oxidized by C1207, formed by dehydration of perchloric acid, to CO and NaS03CH3 465 In spite of the fact that epe was conducted well below the discharge potential of the supporting electrolyte complications arose (Eq. (220) ), that were attributed to anodically generated C104 This observation asks for caution in the use of perchlorates as supporting electrolytes in apro-tic solvents. If possible, tetrafluoroborates or hexafluorophosphates should be used instead. 

Berthelot s observations are confirmed by the experiments of A. Slosse,2 who, by subjecting a mixture of 1 volume carbon monoxide and 2 volumes hydrogen to the induction action in an ozonizer, obtained a crystalline, fermentable sugar which could have been formed from formaldehyde and methyl alcohol— both of which can be shown to be present—by the further action of the discharge ... 

Monochloromethyl ether has been prepared by saturating an aqueous solution of formaldehyde and methyl alcohol with hydrogen chloride 1 and by saturating a solution of trioxymethyl-ene in methyl alcohol with hydrogen chloride.2 The method which is described in the procedure is essentially that developed by Henry.3... 

Trace quantities of formaldehyde and methyl glyoxal in aqueous and food samples were determined by a newly developed method. Formaldehyde and methyl glyoxal were reacted with cysteamine in aqueous medium or food sample to give thiazolidine and 2-acetylthiazolidine, respectively, at pH 6 and 8. Thiazolidine derivatives formed from formaldehyde and methyl glyoxal were extracted with dichlorometh-ane or chloroform and subsequently analyzed by a gas chromatograph equipped with a fused silica capillary column and a thermionic detector. Seventeen commercial food items were analyzed for formaldehyde and methyl glyoxal. The quantities of formaldehyde and methyl glyoxal varied from 0 to 17 ppm and from 0 to 620 ppm, respectively. 

Certain volatile aldehydes such as formaldehyde and methyl glyoxal have always presented some difficulties in the determination of their levels in foods and beverages. Formaldehyde is difficult to extract from an aqueous solution with an organic solvent because it is very water soluble or exists as a polymer in an aqueous media. Methyl glyoxal is also hard to recover from food samples because it exists as a copolymer with some amines such as amino acids and proteins. 

Methyl glyoxal has been found in many foods, such as bread ( 3 ), boiled potatoes (4 ), roast turkey (5 ), and tobacco smoke (6 ). It is a well known fact that sugar caramelization produces numerous carbonyls including formaldehyde and methyl glyoxal ( 7). Among... 

Since direct analyses for formaldehyde and methyl glyoxal are difficult with gas chromatography (GC) or any other methods, we attempted to determine levels of formaldehyde and methyl glyoxal in various food samples using their derivatives thiazolidine and 2-acetylthiazolidine, respectively. The proposed mechanism of thiazolidine formation from cysteamine and corresponding aldehydes is shown in Figure 1. 

Instrumental Analysis. A Hewlett-packard Model 5880 A GC, equipped with thermionic specific detector and a 50 m x 0.23 mm i.d. fused silica capillary column coated with Carbowax 20m, was used for quantitative analysis of thiazolidine and 2-acetylthiazolidine derived from formaldehyde and methyl glyoxal, respectively. GC peak areas were calculated with a HP 5880 A series GC integrator. The oven temperature was programmed from 70 to 180°C at 2 C/min. A Finnigan Model 3200 combination GC/MS equipped with an INCOS MS data system was used for mass spectral identification of thiazolidine derivatives. 

Analysis of formaldehyde and methyl glyoxal in food samples. The... 

The results of formaldehyde and methyl glyoxal analysis in commercial foods are shown in Table VIII. Formaldehyde was identified in the levels of 3.7-17 ppm in coffee obtained from various commercial sources. It was found at higher levels in instant coffees than in brewed coffee. This suggests that formaldehyde may escape from coffee during brewing. Formaldehyde has been reported in coffee volatiles by several researchers (31). There are however, no reports on quantitative analysis of formaldehyde in coffee prior to the present study. 

The samples examined in this study can be classified into two groups. One is foods consumed without additional water (Group I) and the other is foods consumed with addition of a certain amount of water (Group II). It is important to know the amount of formaldehyde and methyl glyoxal intake when a food is consumed. 

Since formaldehyde and methyl glyoxal have been proven to be genotoxic and are found in various foods and beverages in somewhat significant quantities, it is important to study further their risk to human health. 

Finally, it should be realized that CO is not the only fuel (or fuel-derived) contaminant expected to affect anode performance in the PEFC. In a test of other possible contaminants that could result, in principle, from methanol reforming, Seymour et al. [27] reported strong and irreversible effects of formic acid at a PEFC platinum (high-loading) anode, whereas methanol, formaldehyde, and methyl formate were found to have much smaller and reversible effects. The fuel impurity aspects of coupling between natural gas (or gasoline) reformers of various types and a PEFC stack are even wider, and make it essential to probe and address, either by removal upstream or by use of modified catalysts, the possible detrimental effects of low levels of sulfur, H2S, COS, and NH3 [28]. 

In the multicenter study of the Information Network of Departments of Dermatology, sensitization rates of preservatives in the standard series were all over 1% in the test population of 11485 patients. Thiomersal was rating highest (5.3%), chloromethyl-isothiazolinone/methyi-sothiazolinone, formaldehyde, and methyl-dibromo-glutaronitrile/phenoxyethanol were next at about 2%, and parabens rating lowest at 1.6%. Glutaral, a biocide... 

Oxidation-reduction reactions Many organic compounds can be converted to other compounds by oxidation and reduction reactions. For example, suppose that you wish to convert methane, the main constituent of natural gas, to methanol, a common industrial solvent and raw material for making formaldehyde and methyl esters. The conversion of methane to methanol may be represented by the following equation, in which [O] represents oxygen from an agent such as copper(II) oxide, potassium dichromate, or sulfuric acid. 

Condenaation, of Formaldehyde and Methyl Acetate over HY Catcdyaf ... 

As shown in Table XXIV, crystalline aluminosilicates, notably, hydrogen zeolites, also catalyze the conversion of formaldehyde and methyl acetate to methyl acrylate ... 

Over NaY and NaX, the only reaction products are CO, CO2, HCI and formaldehyde over HFAU, methyl chloride is also observed but only above 380°C. No formation of CI2 was detected over the three catalysts. Furthermore, no organic products other than formaldehyde and methyl chloride can be observed. 

In an acid-catalyzed aminomethylation sequence, 6-methyl-4-phenyI-3,4-dihydropyrimidinc-2(l//)-thione (1) with formaldehyde and methyl- or benzylamine/hydrochloric acid affords 6-aIkyl-4-phenyl-3,4,4a,5,6,7,8,8a-octahydropyrido[4,3-d]pyrimidine-2(l//)-lhiones 2. Depending on the solvent, the 8a-position bears a hydroxy or ethoxy substituent.524... 

The oxidation of isoprene, CH2=CHC(CH3)=CH2, in the atmosphere has not yet been fully delineated and thus remains speculative. Hanst et al. (1980) have discussed some of several possibilities. The successive addition of OH and 02 to either of the two double bonds of isoprene may be modeled in analogy of that to propene and is expected to give formaldehyde and methacroleine or formaldehyde and methyl vinyl ketone as the products. The reaction of isoprene with ozone is expected to produce dioxirane and... 

Hofmann (53) found an appreciable amount of formaldehyde (about 25%) and small amounts of methyl formate during the decomposition of zinc formate. Lithium formate produced acetone (about 20%) from lead formate, formaldehyde and methyl alcohol were formed. Pichler (127) found that during the decomposition of calcium formate, oxalate was formed. In general it appeared that the nature and the amount of the organic by-products depended largely on the reaction conditions [Hofmann (53)]. 

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