Production Paraformaldehyde

The second patent80 describes the conversion of ethylene into ethylene ozonide followed by the immediate decomposition of the latter into formaldehyde. The primary object in this process is to so regulate the reaction as to produce a large yield of formaldehyde or its polymerization product, paraformaldehyde, while reducing the formation of formic acid to a minimum. The procedure is similar to that which has been described in the case of the preceding patent and differs principally in the fact that no catalyst is employed. For example, ethylene, ozonized air and water vapor are introduced into a drum, tower, or other convenient form of apparatus which will facilitate an intimate mixture of the substances. The following reactions are supposed to occur ... 

This is the least desirable of all three processes [What do you mean by that This is really easy to do And the yield are fine ]. The yields are lower than the two rearrangements, and it requires substantial labor to get a decently pure product. Not "labor" as In difficult but "labor" as in a lot of it. I would suggest this only for those who have a large supply of Formaldehyde available to them (note - N. Coffey found formaldehyde at Home Depot - look for "Mildewcide" and dissolve it in enough water to make a 37% solution to depolymerize the paraformaldehyde). 

Starch is subject to fermentation by many microorganisms and, unless the mud is saturated with salt or the pH is >11.5, a preservative or biocide must be added if the mud is to be used for an extended period of time. The most common biocide until the mid-1980s was paraformaldehyde [9002-81-7]. This material has been largely replaced by isothia2olones (at 5—10 ppm cone) (74), carbamates, and glutaraldehyde [111-30-8]. Alternatively, the biocide may be incorporated during the processing of the starch and is present in the commercial product. 

Another significant use of 3-methylphenol is in the production of herbicides and insecticides. 2-/ f2 -Butyl-5-methylphenol is converted to the dinitro acetate derivative, 2-/ f2 -butyl-5-methyl-4,6-dinitrophenyl acetate [2487-01 -6] which is used as both a pre- and postemergent herbicide to control broad leaf weeds (42). Carbamate derivatives of 3-methylphenol based compounds are used as insecticides. The condensation of 3-methylphenol with formaldehyde yields a curable phenoHc resin. Since 3-methylphenol is trifunctional with respect to its reaction with formaldehyde, it is possible to form a thermosetting resin by the reaction of a prepolymer with paraformaldehyde or other suitable formaldehyde sources. 3-Methylphenol is also used in the production of fragrances and flavors. It is reduced with hydrogen under nickel catalysis and the corresponding esters are used as synthetic musk (see Table 3). 

Formaldehyde. Pure formaldehyde, CH2O, is a colorless, pungent smelling reactive gas (see Formaldehyde). The commercial product is handled either as soHd polymer, paraformaldehyde (13), or in aqueous or alcohoHc solutions. Marketed under the trade name Formcel, solutions in methanol, / -butanol, and isobutyl alcohol, made by Hoechst-Celanese, are widely used for making alcohol-modified urea and melamine resins for surface coatings and treating textiles. 

Alkylation involving formaldehyde in the presence of hydrogen chloride is known as chloromethylation (eq. 3). The reagent may be a mixture of formalin and hydrochloric acid, paraformaldehyde and hydrochloric acid, a chloromethyl ether, or a formal. Zinc chloride is commonly employed as a catalyst, although many other Lewis acids can be used. Chloromethylation of sahcyhc acids yields primarily the 5-substituted product 5-chlotomethylsahcyhc acid [10192-87-7] (4). 

The dihydroxyacetone side chain is conveniently protected by forming 17a,20 20,21-bismethylenedioxy compounds (BMD) (92). Formation of llf -ethers as by-products from 11 -hydroxycompounds (91) can be limited by using formalin with a low methanol content, or better with paraformaldehyde as a source of alcohol-free formaldehyde. ... 

When catalyzed by acids, low molecular weight aldehydes add to each other to give cyclic acetals, the most common product being the trimer. The cyclic trimer of formaldehyde is called trioxane, and that of acetaldehyde is known as paraldehyde. Under certain conditions, it is possible to get tetramers or dimers. Aldehydes can also polymerize to linear polymers, but here a small amount of water is required to form hemiacetal groups at the ends of the chains. The linear polymer formed from formaldehyde is called paraformaldehyde. Since trimers and polymers of aldehydes are acetals, they are stable to bases but can be hydrolyzed by acids. Because formaldehyde and acetaldehyde have low boiling points, it is often convenient to use them in the form of their trimers or polymers. 

In another example, a sequence of methylation-elimination-hydroxymethylation was used to install the functionality pattern found in the A-ring of taxol. The hydrazone dianion was generated and methylated at low temperature. The hydrazone was then deprotonated again using excess n-butyllithium and allowed to warm to room temperature, at which point formation of the vinyllithium occurred. Reaction with paraformaldehyde generated the desired product.290... 

In the particular scenario of the reaction of ie.vo-tctrakis(pcntafluorophenyl)porphyrin Id with the azomethine ylide, generated in situ from /V-mcthylglycine and paraformaldehyde, in refluxing toluene during 15 hours, the pyrrolidinochlorin derivative 62 was obtained as the main product (Scheme 19), together with a small amount of isobacteriochlorin 63 (bis-adduct, Figure 5). 

In a 500 cc. round-bottomed flask attached to a reflux condenser are placed 60 g. (58.5 cc., 0.5 mole) of acetophenone (Note 1), 52.7 g. (0.65 mole) of dimethylamine hydrochloride, and 19.8 g. (0.22 mole) of paraformaldehyde. After the addition of 1 cc. of concentrated hydrochloric acid (sp. gr. 1.19) in 80 cc. of 95 per cent ethyl alcohol, the mixture is refluxed on a steam bath for two hours (Note 2). The yellowish solution is filtered, if it is not clear (Notes 3 and 4), and is transferred to a 1-1. wide-mouthed Erlenmeyer flask. While still warm, it i6 diluted by the addition of 400 cc. of acetone (Note 5), allowed to cool slowly to room temperature, and then chilled overnight in the refrigerator. The large crystals are filtered and washed with 25 cc. of acetone. After it has been dried for two and one-half hours at 40-50°, this crude product weighs 72-77 g. (68-72 per cent of the theoretical amount) and melts at 138-141° (Notes 6 and 7) it is suitable for many reactions. 

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