Formic acid effectiveness

ArCHO - ArCOOH. Hydrogen peroxide in formic acid effects this transformation. However, methoxybenzaldehydes are reported to give phenols. ... 

Colmati F, Antohni E, Gonzalez ER. Ethanol oxidation on a carbon-supported Pt75Sn2s electrocatal5Tst prepared by reduction with formic acid Effect of thermal treatment. App Cat B Env 2007 73 106-15. 

Chitosan/ PAAand chitosan/ PAMPS Formic acid Effect of pH on integrity. [182]... 

Method, Formaldehyde may be estimated in solution by oxidising it to formic acid by means of a known quantity (in excess) of iodine dissolved in a excess of NaOH solution. The oxidation is, in effect, carried out by the odium hypo-iodite formed by the action of the iodine on the alkali, the formic cid being then neutralised by the alkali present ... 

The HSAB pattern may also be reversed by steric effects a Japanese patent describes the preparation of 3-(4-R-thiazolyl-2)thioallophanic acid esters (151) by reaction between 2-amino-4-R-thiazoles (4-R = H or low alkyl) and isothiocyanate formic acid ester (Scheme 96) (309). 

Formic acid exhibits many of the typical chemical properties of the aHphatic carboxyHc acids, eg, esterification and amidation, but, as is common for the first member of an homologous series, there are distinctive differences in properties between formic acid and its higher homologues. The smaller inductive effect of hydrogen in comparison to an alkyl group leads, for example, to formic acid = 3.74) being a considerably stronger acid than acetic acid... 

In appHcations as hard surface cleaners of stainless steel boilers and process equipment, glycoHc acid and formic acid mixtures are particularly advantageous because of effective removal of operational and preoperational deposits, absence of chlorides, low corrosion, freedom from organic Hon precipitations, economy, and volatile decomposition products. Ammoniated glycoHc acid Hi mixture with citric acid shows exceUent dissolution of the oxides and salts and the corrosion rates are low. 

Methanol is not classified as carcinogenic, but can be acutely toxic if ingested 100—250 mL may be fatal or result in blindness. The principal physiological effect is acidosis resulting from oxidation of methanol to formic acid. Methanol is a general irritant to the skin and mucous membranes. Prolonged skin contact with methanol vapor or Hquid can cause dermatitis. Methanol vapor can cause eye and respiratory tract irritation, nausea, headaches, and dizziness. 

Activators. Activators are often added to removers to make them more efficient. Acids such as phenol [108-95-2] phosphoric acid [7664-38-2] acetic acid [64-19-7] formic acid [64-18-6]., and citric acid [5949-29-1] are used to increase the cutting abiHty on epoxide-type paints and other modem finishes. Strongly alkaline activators are effective on enamel andlatex paints. Other activators include ammonia [7664-41-7] monoethyl amine [75-04-7], and /V-phenyIdiethan ol amines. Acid and base activators shorten the shelf life of some removers. 

Nylon-11. Nylon-11 [25035-04-5] made by the polycondensation of 11-aminoundecanoic acid [2432-99-7] was first prepared by Carothers in 1935 but was first produced commercially in 1955 in France under the trade name Kilsan (167) Kilsan is a registered trademark of Elf Atochem Company. The polymer is prepared in a continuous process using phosphoric or hypophosphoric acid as a catalyst under inert atmosphere at ambient pressure. The total extractable content is low (0.5%) compared to nylon-6 (168). The polymer is hydrophobic, with a low melt point (T = 190° C), and has excellent electrical insulating properties. The effect of formic acid on the swelling behavior of nylon-11 has been studied (169), and such a treatment is claimed to produce a hard elastic fiber (170). 

Azoic Dyes. These are used to produce cost-effective heavy yellow, orange, red, maroon, navy blue, brown, and black shades and are ptinted alongside other dye classes to extend the coloristic possibiUties for the designer. Two approaches are adopted. The common method ia the United States is to use both a naphthol derivative and a stabilized color base, usually in the form of a diazo imino compound in the same print paste. This mixture is soluble in dilute caustic soda and no coupling takes place at this stage. The dried prints are passed through steam at 100—105°C that contains acetic and/or formic acid vapor. As neutralization takes place on the print, the coupling occurs rapidly and the insoluble azoic dye is formed. 

Nylons 46, 6, 66, 610, 11 and 12 are polar crystalline materials with exceptionally good resistance to hydrocarbons. Esters, alkyl halides, and glycols have little effect. Alcohols generally have some swelling action and may in fact dissolve some copolymers (e.g. nylon 66/610/6). There are few solvents for the nylons, of which the most common are formic acid, glacial acetic acid, phenols and cresols. 

Shifts in the SEC fractionation range are not new. It has been known for decades that adding chaotropes to mobile phases causes proteins to elute as if they were much larger molecules. Sodium dodecyl sulfate (SDS) (9) and guanidinium hydrochloride (Gd.HCl) (9-12) have been used for this purpose. It has not been clearly determined in every case if these shifts reflect effects of the chaotropes on the solutes or on the stationary phase. Proteins are denatured by chaotropes the loss of tertiary structure increases their hydrodynamic radius. However, a similar shift in elution times has been observed with SEC of peptides in 0.1% trifluoroacetic acid (TEA) (13-15) or 0.1 M formic acid (16), even if they were too small to have significant tertiary structure. Speculation as to the cause involved solvation effects that decreased the effective pore size of the... 

Controlling for these forces requires variation in the amount of salt, organic solvent, and the pFI of the mobile phase. It is impractical to perform such experiments with 50 mM formic acid an alternative additive must be used that maintains its chaotropic properties independent of salt content or pFI. Fortunately, mobile phases containing 50 mM hexafluoro-2-propanol (HFIP) afford a fractionation range comparable to that of the formic acid (Fig. 8.6), permitting the effects of these variables to be studied systematically. 

FIGURE 8.6 Comparison of hexafluoro-2-propanol (HFIP) with formic acid as a denaturing agent in SEC. Eiution positions of neutral amino acids were similar with both agents. The elution positions of Lys and Asp shifted dramatically in C, as shown by the tie lines, but this was an effect of pH (see Fig. 8.7). The elution positions of a-MSH and formic acid are shown to demonstrate that the amino acids eluted within Vo and V,. Column Same as Fig. 8.1. Flow rate 1.0 ml/min. Mobile phase As noted. Detection Aiij = 0.1 AUFS. 

Experimental pKa data suggests that simple alkyl groups all affeet acid-base reactivity in roughly the same way. What is more, this universal alkyl effect is roughly equivalent to the effect of a hydrogen atom. For example, the difference in pKa between water and ethanol is approximately the same as that between formic acid and propanoic acid (see table at right). 

The presence of 2% formic acid in acetic acid has relatively little effect on the corrosion of the metal. Among the impurities added at the 0-2% level to 10% acetic acid, only mercuric chloride caused an appreciable increase in corrosion rate (0-71 mm/y), and all the other additions appeared to inhibit corrosion. 

Molybdenum tends to be protected by vanadium in aerated 7 1 % hydrochloric acid and it receives a high degree of protection when coupled with copper in this medium. Molybdenum corrodes somewhat faster than normal in 3 1 % nitric acid when coupled with tungsten. It is not affected by contact with titanium in 3-1% nitric acid. It is protected by aluminium and copper in aerated 10% formic acid and by aluminium in air-aerated 9% oxalic acid. In the latter solution, copper had only a slight protective effect when coupled with molybdenum. 

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