Formaldehyde, 31 Table

Under the right conditions, glyoxal fixatives form adducts with the same groups listed for formaldehyde (Table 12.1). We do not know if compound... 

Shapiro s data for formaldehyde (Table 16) are quite limited, but clearly show a solvent induced decrease for VH D (which is multiplied by the ratio of the gyromagnetic constants of H and D to yield the H—H coupling) going from TMS to acetonitrile. 

The resorcinol and phloroglucinol derivatives (Table IV) all precipitated rather completely as expected except for 3,5- and 2,4-dihydroxy-benzoic acids. Their precipitation was enhanced if phloroglucinol was added this indicates that formaldehyde substitution occurred but the products were too soluble and too polar to precipitate until crosslinked with phloroglucinol. It had been shown previously that phenols which did not react with formaldehyde were not appreciably entrained in the precipitate formed with those which did (21) (see Table X). Hydro-quinone derivatives, except for one which is also a resorcinol derivative, did not precipitate with formaldehyde (Table V). 

Raising the pressure increased the yield of ethanol, acetaldehyde, and acetic add, i.e., C2-products formed without breaking the C—C bond, and reduced the deld of methanol and formaldehyde (Table 10.1). Note that, in these experiments, the reaction temperature was also changed, possibly to keep the reaction time within certain limits (2.5—4.5 min) (Table 10.1) achieving the maximum yield of alcohols at each pressure was not pursued. At pressures above 50 atm, the maximum yield of alcohol and acetaldehyde was weakly dependent on pressure, but the yield of acetic acid increased with pressure up to 100 atm, at which the maximum selectivity, 24%, was reached. Up to 100 atm, the formaldehyde deld decreased monotoni-cally with increasing pressure. 

The monomers discussed thus far have an active bond that may react to form two covalent bonds with other monomers forming a two-dimensional chamUke molecular structure, as indicated earlier for ethylene. Such a monomer is termed bifimctional. In general, the functionality is the number of bonds that a given monomer can form. For example, monomers such as phenol-formaldehyde (Table 14.3) are trifiinctional they have three active bonds, from which a three-dimensional molecular network structure results. 

More precisely, the rate of ozone formation depends closely on the chemical nature of the hydrocarbons present in the atmosphere. A reactivity scale has been proposed by Lowi and Carter (1990) and is largely utilized today in ozone prediction models. Thus the values indicated in Table 5.26 express the potential ozone formation as O3 formed per gram of organic material initially present. The most reactive compounds are light olefins, cycloparaffins, substituted aromatic hydrocarbons notably the xylenes, formaldehyde and acetaldehyde. Inversely, normal or substituted paraffins. 

The type of alcohol produced depends on the carbonyl compound Substituents present on the carbonyl group of an aldehyde or ketone stay there—they become sub stituents on the carbon that bears the hydroxyl group m the product Thus as shown m Table 14 3 (following page) formaldehyde reacts with Grignard reagents to yield pri mary alcohols aldehydes yield secondary alcohols and ketones yield tertiary alcohols... 

Table 5.7 Calculated Values of a and f for Phenol-formaldehyde Resins Formed from Different Proportions of Reactants and Based on Experimental Values of n and n .

Having assigned symmetry species to each of the six vibrations of formaldehyde shown in Worked example 4.1 in Chapter 4 (pages 90-91) use the appropriate character table to show which are allowed in (a) the infrared specttum and (b) the Raman specttum. In each case state the direction of the transition moment for the infrared-active vibrations and which component of the polarizability is involved for the Raman-active vibrations. 

The A A2 X Ai, n -n system of formaldehyde (see Section 7.3.1.2) is also electronically forbidden since A2 is not a symmetry species of a translation (see Table A.l 1 in Appendix A). The main non-totally symmetric vibration which is active is Vq, the hj out-of-plane bending vibration (see Worked example 4.1, page 90) in 4q and d transitions. 

Butynediol. Butynediol, 2-butyne-l,4-diol, [110-65-6] was first synthesized in 1906 by reaction of acetylene bis(magnesium bromide) with paraformaldehyde (43). It is available commercially as a crystalline soHd or a 35% aqueous solution manufactured by ethynylation of formaldehyde. Physical properties are Hsted in Table 2. 

The common method of naming aldehydes corresponds very closely to that of the related acids (see Carboxylic acids), in that the term aldehyde is added to the base name of the acid. For example, formaldehyde (qv) comes from formic acid, acetaldehyde (qv) from acetic acid, and butyraldehyde (qv) from butyric acid. If the compound contains more than two aldehyde groups, or is cycHc, the name is formed using carbaldehyde to indicate the functionaUty. The lUPAC system of aldehyde nomenclature drops the final e from the name of the parent acycHc hydrocarbon and adds al If two aldehyde functional groups are present, the suffix -dialis used. The prefix formjlis used with polyfunctional compounds. Examples of nomenclature types are shown in Table 1. 

As can be seen from Table 4, formaldehyde is cleady the most commercially significant of the aldehydes. Only a small selection of the less commercially significant products ate hsted, however. 

Other examples are glycine — formaldehyde, alanine — acetaldehyde, valine — isobutyraldehyde, phenylalanine — phenylacetaldehyde, and methionine — methional (106). Products such as dried skim milk, dried eggs, and dehydrated vegetables and fmits are particularly susceptible to deteriorative flavor changes ascribed to this reaction (Table 10). 

At ordinary temperatures, pure formaldehyde is a colodess gas with a pungent, suffocating odor. Physical properties are summarized ia Table 1 thermodynamic values for temperatures ranging from 0—6000 K are given ia the Interim Thermochemica/ Tables (11,12). Other properties are Hsted ia... 

In methanol—formaldehyde—water solutions, increasing the concentration of either methanol or formaldehyde reduces the volatility of the other. Vapor-hquid-equihbrium data (8,27) for several methanolic formaldehyde solutions ate given in Table 2. The flash point varies with composition, decreasing from 83 to 60°C as the formaldehyde and methanol concentrations increase (17,18). 

Table 2. Vapor Pressure above Formaldehyde Solutions, kPa ...

U.S. formaldehyde prices for 1966—1989 are shown in Table 4 (115). Since the cost of methanol represents over 60% of formaldehyde s production costs, the formaldehyde price normally reflects the methanol price. Also, freight is a significant cost for formaldehyde since 1—3 kg of water maybe shipped with every kg of formaldehyde. The significant price increase in the early 1970s was due to the sudden rise in hydrocarbon prices caused by the Organization of Petroleum Exporting Companies (OPEC) cartel increasing oil prices. 

Procedures for determining the quaUty of formaldehyde solutions ate outlined by ASTM (120). Analytical methods relevant to Table 5 foUow formaldehyde by the sodium sulfite method (D2194) methanol by specific gravity (D2380) acidity as formic acid by titration with sodium hydroxide (D2379) iron by colorimetry (D2087) and color (APHA) by comparison to platinum—cobalt color standards (D1209). 

Fomialdehyde is a basic chemical budding block for the production of a wide range of chemicals finding a wide variety of end uses such as wood products, plastics, and coatings. Table 6 shows the distribution of formaldehyde production in the United States from 1966 through 1989 (115). Production percentages reported in the following discussion are for the United States. 

Table 6. U.S. Distribution of Formaldehyde Production According to Uses, 1966—1989 ...

Formaldehyde—Alcohol Solutions. These solutions are blends of concentrated aqueous formaldehyde, the alcohol, and the hemiacetal. Methanol decreases the average molecular weight of formaldehyde oligomers by formation of lower molecular weight hemiacetals. These solutions are used to produce urea and melamine resins the alcohol can act as the resin solvent and as a reactant. The low water content can improve reactivity and reduce waste disposal and losses. Typical specifications for commercially available products are shown in Table 7 (117). 

Table 7. Specifications and Physical Properties of Formaldehyde—Alcohol Solutions...

Other Nitrogen Compounds. The basis of the sophisticated nitrogen compounds Hsted in Table 10 is the reaction of formaldehyde with amino compounds. A significant amount of Hterature details investigation of the mechanism of action, particularly whether or not the antimicrobial activity depends on decomposition to formaldehyde (40—42). These compounds tend to have substantial water solubiUty and are more effective against bacteria than fungi and yeasts. Key markets for these compounds are metalworking fluids, cosmetics, and in-can preservation of paints (see Alkanolamines Amines, fatty amines). 

For example, Day-Glo HM Series toners come ia a range of colors suitable for flexographic and gravure inks of the solvent-base type. The Radiant GF Series and Lawter HVT Series are also suitable for this type of apphcation (see Table 2). Generally, these toners are of the formaldehyde—sulfonamide type and requite oxygenated solvents, primarily alcohol—ester blends, for proper solution. For appHcations such as flexographic printing on film, these materials are modified with other resias such as nitrocellulose or polyamides ia the finished ink. 

Daylight fluorescent pigments (qv) are considered to be nontoxic. Since they are combinations of polymers and dyestuffs, the combined effect of the ingredients must be taken into account when considering the net toxic effect of these materials. Table 5 gives results of laboratory animal toxicity tests of standard modified melamine—formaldehyde-type pigments, the Day-Glo A Series, and the products recommended for plastic mol ding, Day-Glo Z-series. 

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