Paraformaldehyde, reaction with ammonium

Bischloromethyl ether has been prepared by saturation of formalin with dry hydrogen chloride by the reaction of paraformaldehyde with phosphorus trichloride or phosphorus oxychloride, by solution of paraformaldehyde in concentrated sulfuric acid and treatment with ammonium chloride or dry hydrogen chloride, and by suspension of paraformaldehyde in seventy or eighty percent sulfuric acid and treatment with chlorosulfonic acid. It is formed together with the asymmetrical isomer when methyl ether is chlorinated and when paraformaldehyde is treated with chlorosulfonic acid. The present method has been published. ... 

Reaction of paraformaldehyde with ammonium nitrate in the presence of acetic anhydride... 

Hexamine dinitrate is reacted with ammonium dinitrate in the presence of acetic anhydride. Unlike the E-method no paraformaldehyde is used, all the necessary methylene groups being provided by hexamine, and the additional amino groups (as in the K-method) by ammonium nitrate. Nitric acid enters into reaction in combination with hexamine and as ammonium dinitrate ... 

Derivation (1) The reaction product of paraformaldehyde and sulfuric acid is treated with ammonium bromide (2) interaction of hydrobromic acid and paraformaldehyde. 

The Mannich reaction with dibenzeneketone, paraformaldehyde, and ammonium acetate in a 1 4 2 ratio yields l,5-diphenylbispidine-9-one (74). There was a controversy about the reaction pathway until it was shown that the initial product was 5,7-diphenyl-l,3-diazaadamantane-6-one (88). Following this observation the synthesis of various l,3-diazaadamantane-6-ones with different substituents in the 5,7-position was reported (88-90), and these compounds found their way into the preparation of bispidine derivatives. 

Some other reported curing agents are quinone [81], chloranil [81], anhydroformaldehyde aniline [82], methylolureas and melamines [83], ethylenediamine-formaldehyde products, and paraformaldehyde. Resorcinol novolac resins can be cured with paraformaldehyde [84] and the mildly acid nature of resorcinol helps to catalyze the curing reaction [84]. Ammonium salts have also been reported as accelerators for the curing of phenolic resins [85]. 

The phospha-Mannich condensation of a-, (3- and y-amino acetals, paraformaldehyde and secondary phosphine oxides led to a),(i)-dialko g -all laminomethylphosphine oxides whose reaction with resorcinols or pyrogallol in boiling trifluoroacetic acid afforded (diallg lphosphinoyl-methyl-)(o),a)-diaiylallgrl)ammonium trifluoroacetates (Scheme 41). ... 

Mix 100 g. of ammonium chloride and 266 g. of paraformaldehyde in a 1-litre rovmd-bottomed flask fitted with a long reflux condenser containing a wide inner tube (ca. 2 cm. diameter) the last-named is to avoid clogging the condenser by paraformaldehyde which may sublime. Immerse the flask in an oil bath and gradually raise the temperature. The mixture at the bottom of the flask liquefies between 85° and 105° and a vigorous evolution of carbon dioxide commences at once remove the burner beneath the oil bath and if the reaction becomes too violent remove... 

The nitro alcohols available in commercial quantities are manufactured by the condensation of nitroparaffins with formaldehyde [50-00-0]. These condensations are equiUbrium reactions, and potential exists for the formation of polymeric materials. Therefore, reaction conditions, eg, reaction time, temperature, mole ratio of the reactants, catalyst level, and catalyst removal, must be carefully controlled in order to obtain the desired nitro alcohol in good yield (6). Paraformaldehyde can be used in place of aqueous formaldehyde. A wide variety of basic catalysts, including amines, quaternary ammonium hydroxides, and inorganic hydroxides and carbonates, can be used. After completion of the reaction, the reaction mixture must be made acidic, either by addition of mineral acid or by removal of base by an ion-exchange resin in order to prevent reversal of the reaction during the isolation of the nitro alcohol (see Ion exchange). 

A mixture of Mg (0.163 g atom) and chloromethyltrimethylsilane (0.163 mol) in ether (90 ml) was heated gently (air-gun) to initiate reaction (once started, the reaction can be very exothermic, and it should be cooled occasionally to maintain a gentle reflux). When all the Mg had dissolved, paraformaldehyde (5g, 0.166mol of CH20) was added, and reflux was continued for a further 2.25 h. The cooled mixture was diluted with ether, and washed with saturated ammonium chloride solution. The aqueous layer was re-extracted with ether, and the combined ethereal extracts were dried and concentrated. Distillation gave 2-trimethylsilylethanol (0.156mol, 96%), b.p. 34-35°C/1 mmHg. 

Variations in the conditions used for the nitrolysis of hexamine have a profound effect on the nature and distribution of isolated products, including the ratio of RDX to HMX. It has been shown that lower reaction acidity and a reduction in the amount of ammonium nitrate used in the Bachmann process increases the amount of HMX formed at the expense of Bachmann and co-workers ° were able to tailor the conditions of hexamine nitrolysis to obtain an 82 % yield of a mixture containing 73 % HMX and 23 % RDX. Continued efforts to provide a method for the industrial synthesis of HMX led Castorina and co-workers to describe a procedure which produces a 90 % yield of a product containing 85 % HMX and 15 % RDX. This procedure conducts nitrolysis at a constant reaction temperature of 44 °C and treats hexamine, in the presence of a trace amount of paraformaldehyde, with a mixture of acetic acid, acetic anhydride, ammonium nitrate and nitric acid. Bratia and co-workers ° used a three stage aging process and a boron trifluoride catalyst to obtain a similar result. A procedure reported by Picard " uses formaldehyde as a catalyst and produces a 95 % yield of a product containing 90 % HMX and 10 % RDX. 

Manufacture at Bobingen [38,61] was on the following lines. A reactor of aluminium or stainless steel (capacity 1.2 m3) is filled with acetic anhydride and then 0.4% of BF3 is added. Acetic anhydride is warmed to 60-65°C and at this temperature ammonium nitrate and paraformaldehyde are added gradually. Due to the high temperature and the presence of boron fluoride the reaction starts at once and heat is evolved. The heating is then turned off and the temperature maintained by cooling, within the range 60-65°C. The addition of the reactants requires approximately 6 hr, after which the contents of the reactor are cooled to 20°C. The precipitated cyclonite is separated from the solution on a vacuum filter. The by-products remain in the spent liquor. 

The reaction of amines with 1,2-diketo substrates led to a variety of substituted imidazole derivatives. Treatment of various substituted anilines 88 with glyoxals 89 gave the imine intermediate 90, which was then cyclized to the 1-arylimidazoles 91 with paraformaldehyde and ammonium chloride under acidic conditions <0382661>. A one-pot, three-component condensation of benzil 92, benzonitrile derivatives and primary amines on the surface of silica gel under solvent-free conditions and microwave irradiation provided tetrasubstituted imidazoles 93<03TL1709>. 

Under the protection of nitrogen, compound 3.58 (140 mg, 0.29 mmol) was dissolved in tetrahydrofuran (10 mL). Potassium tert-butoxide (0.29 mL, 0.29 mmol) was then added at 0 °C. The reaction was stirred at 0 °C for 30 min. Paraformaldehyde (87 mg, and 2.9 mmol) was quickly added, with continued stirring at 0 °C for 30 min. TLC showed that the reaction was completed. The reaction was quenched by saturated ammonium chloride solution (10 mL). The water phase was extracted with ethyl acetate (3 x 10 mL), and the organic phase was washed with saturated brine (2 x 10 mL). The combined organic phase was dried over anhydrous sodium sulfate. After filtration, the solvent was removed by reduced pressure. The resulting crude product was separated by flash column chromatography (PE/EA = 3 1) to give 99 mg colorless liquid (/ /= 0.85, PE/ EA = 1 1), yield 95 %. 

To a 1-liter, three-necked round-bottomed flask equipped with a mechanical stirrer. Dean Stark trap, and condenser are added 400 gm (0.63 mole) of tetrabromobisphenol A diethanol and 460 ml of benzene. The reaction mixture is heated to reflux for 2 hr to form a clear solution. The temperature is lowered to 65°C, and 20.6 gm (0.65 mole) of 95% paraformaldehyde and 2.0 gm of /7-toluenesulfonic acid are added. The mixture is stirred for 1-jhr at 65°C, and then the temperature is raised to reflux to remove 11.4 ml (0.63 mole) of water azeotropically in about 3yhr. The mixture is cooled to room temperature, and 0.5 ml of 15M ammonium hydroxide is added with vigorous agitation in order to neutralize the catalyst. The polymer is isolated by slowly adding the viscous benzene... 

---