Solutions, formaldehyde Steam

Nitric acid Formaldehyde Steam (260°C) H2SO4 + CUSO4 solutions NaOH + sulfide solutions H2SO4 + chloride solutions Na2C03 + 0.1% NaCl solutions Cone, boiler water NaHCOs -F NH3 + NaCl solutions Nickel alloys (Monel, etc.)... 

In a 500 ml. three-necked flask, fitted with a reflux condenser and mechanical stirrer, place 121 g. (126-5 ml.) of dimethylaniline, 45 g. of 40 per cent, formaldehyde solution and 0 -5 g. of sulphanilic acid. Heat the mixture under reflux with vigorous stirring for 8 hours. No visible change in the reaction mixture occurs. After 8 hours, remove a test portion of the pale yellow emulsion with a pipette or dropper and allow it to cool. The oil should solidify completely and upon boiling it should not smell appreciably of dimethylaniline if this is not the case, heat for a longer period. When the reaction is complete, steam distil (Fig. II, 41, i) the mixture until no more formaldehyde and dimethylaniline passes over only a few drops of dimethylaniline should distil. As soon as the distillate is free from dimethylaniline, pour the residue into excess of cold water when the base immediately solidifies. Decant the water and wash the crystalline solid thoroughly with water to remove the residual formaldehyde. Finally melt the solid under water and allow it to solidify. A hard yellowish-white crystalline cake of crude base, m,p. 80-90°, is obtained in almost quantitative yield. RecrystaUise from 250 ml. of alcohol the recovery of pure pp -tetramethyldiaminodiphenylmethane, m.p. 89-90°, is about 90 per cent. 

To 500 g. (3.85 moles) of freshly distilled ethyl acetoacetate in a i-l. flask set in ice and well cooled, are added 152 g. (2.0 moles) of 40 per cent aqueous formaldehyde solution and 20-25 drops of diethylamine. The flask and contents are kept cold for six hours and are then allowed to stand at room temperature for forty to forty-five hours. At the end of this time two layers are present, a lower oily layer and an upper aqueous layer. The layers are separated, and the aqueous layer is extracted with 50 cc. of ether. The ether solution is added to the oily layer, and the resulting solution is dried over 30 g. of calcium chloride. The ether is then removed by distillation on a steam bath. The residue, amounting to approximately 500 g., is diluted with an equal volume of alcohol and is thoroughly cooled in an ice bath. Ammonia is then passed into the mixture until the solution is saturated. This requires from four to eight hours, and during this time the flask is kept packed in ice. The ammoniacal alcoholic solution is allowed to stand at room temperature for forty to forty-five hours. Most of the alcohol is now evaporated the residue is cooled, and the solid i,4-dihydro-3,5-dicarbethoxy-2,6-dimethylpyridine is removed from the remaining alcohol on a suction filter. The dried ester melts at 175-180 and amounts to 4ro-435 g. (84-89 per cent of the theoretical amount). 

To 217 grams (0.456 mol) of N,N -bis[1-methyl-3-(2,2,6-trimethylcyclohexyl)propyll-I.B-hexanediamine were added 182 ml (3.04 mols) of formic acid (90%). The resulting colorless solution was cooled, then 91.3 ml (1.043 mols) of formaldehyde (37%) were added. The solution was heated at steam temperature with occasional shaking for 2 hours and then refluxed for 8 hours. The volatiles were distilled off at steam temperature under water vacuum and the residual oil was made strongly alkaline with 50% potassium hydroxide. 

Forty-seven grams (0.5 mol) of phenol, 80 mL of 37 wt % aqueous formaldehyde (1.0 mol), and 100 mol of 4 A NaOH were charged to a flask equipped with a reflux condenser and mechanical stirrer. The reaction mixture was stirred at room temperature for 16 h, then heated on a steam bath for 1 h. The mixture was cooled and the pH adjusted to 7.0. The aqueous layer was decanted from the viscous brown liquid product, the wet organic phase was taken up in 500 mL of acetone and dried over anhydrous MgSCL, then over molecular sieves. The dried acetone product solution was filtered and evaporated to yield a water-free light brown syrup. 

Formaldehyde gas for use in sterilization is produced by heating formalin (37% wA aqueous solution of formaldehyde) to a temperature of 70-75°C with steam, leading to the proeess known as LTSF. Formaldehyde has a similar toxicity to ethylene oxide and although absorption to materials appears to be lower similar desorption routines are leeommended. A major disadvantage of formaldehyde is low penetrating power and this limits the packaging materials that eanbe employed to principally paper and eotton fabrie. 

Liberation of methanol during decomposition of 1-methoxy-heptyl-l-hydroperoxide was demonstrated by holding a hot copper wire in the vapor. The odor of formaldehyde was detected. From the solution, the oxime of heptaldehyde was obtained (m.p., 54-55.5°C.) undepressed in admixture with an authentic sample. (Found C, 65.16 H, 11.55 N, 10.83%. C7Hi5ON requires C, 65.07 H, 11.70 N, 10.84%.) Another sample of the hydroperoxide (0.73 gram) was boiled for a few minutes with dilute H2S04. The solution was cooled, excess of sodium hydroxide was added, and the mixture was boiled under reflux for 1.5 hours, then acidified and steam-distilled. The ether extract of the distillate was separated into neutral and acid (0.071-gram) fractions. From the latter, the amide of heptoic acid (m.p. 92-94°C.) was obtained. 

In a 5-I. round-bottom flask fitted with a stopper holding a condenser set for downward distillation and a thermometer which will extend well into the liquid, are placed 4000 g. of technical formaldehyde (35-40 per cent sp. gr. 1.078 at 20°) and 2000 g. of technical ammonium chloride. The mixture is heated on the steam bath until no more distillate comes over and then over a flame until the temperature of the solution reaches 104°. The temperature is held at this point until no more distillate comes over (four to six hours). The distillate, which consists of methylal, methyl formate and water, may be treated as described in Note 3,... 

A portion of the reaction solution was acidified with sulfuric acid and steam-distilled into sodium hydroxide solution. The distillate was found to contain formaldehyde and formic acid. The formaldehyde was identified by precipitation with dimedone (31). The precipitate had a melting point of 186.0-86.5° C. as... 

To 200 ml. of glacial acetic acid in a 1-1. round-bottomed flask is added slowly, with cooling in an ice bath, 151 ml. (54 g. of di-methylamine, 1.2 mole) of 40% aqueous dimethylamine solution, followed by 90 ml. (36 g. of formaldehyde, 1.2 mole) of 37% aqueous formaldehyde (formalin) solution. The flask is removed from the ice bath and equipped with a reflux condenser, through which 82 g. (90 ml., 1 mole) of 2-methylfuran (Note 1) is added all at once. Upon gentle swirling of the flask, an exothermic reaction may set in spontaneously if it does not, the flask is heated on a steam bath until reaction commences. In any event, the spontaneous reaction is allowed to proceed without further external heating. When it ceases, the reaction mixture is heated on a steam bath for another 20 minutes, cooled, and without delay poured into a cold solution of 250 g. of sodium hydroxide (Note 2) in 800 ml. of water. 

Acidity (as acetic acid) Mix 38 mL of sample with an equal volume of carbon dioxide-free water, add 0.1 mL of phenol-phthalein TS, and titrate with 0.1 A sodium hydroxide. Not more than 0.1 mL is required to produce a pink color. Aldehydes (as formaldehyde) Prepare a Sample Solution by diluting 2.5 mL of sample with 7.5 mL of water. Prepare a Standard Solution containing 40 p,g of formaldehyde in 10 mL of water. Add 0.15 mL of a 5% solution of 5,5-dimethyl-1,3-cyclohexanedione in alcohol to each solution, and evaporate on a steam bath until the Acetone is volatilized. Dilute to 10 mL with water, and cool quickly in an ice bath while stirring vigorously. Any turbidity produced in the Sample Solution does not exceed that produced in the Standard Solution. 

Application To produce aqueous formaldehyde (AF) or urea formaldehyde precondensate (UFC) from methanol using Haldor Tbpspe A/S FK-Series iron/molybdenum-oxide catalysts. Description The process is carried out in a recirculation loop at low pressure (0 to 6 psig) (1 to 1.5 bar abs). Vaporized methanol is mixed with air and recycle gas that were boosted by the blower (1). The mixture may be preheated to about 480°F (250°C) in the optional heat exchanger (2) or it may be sent directly to the reactor (3). In the reactor, methanol and oxygen react in the catalyst-filled tubes to make formaldehyde. Reaction heat is removed by an oil heat transfer medium (HTM). The reacted gas exits the reactor at approximately 540°F (290°C) and is cooled in the LP steam boiler (4) to 260°F (130°C) before entering the absorber (5). In the absorber, the formaldehyde is absorbed in water or urea solution. Heat is removed by one or two cooling circuits (6, 7). From the lower circuit (6)... 

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