DE1495465C - Process for the production of paraformal dehydration - Google Patents

Claims (1)

1 . 2 It is known that one can use paraformaldehyde. Immediately after its formation, drainage of aqueous formaldehyde solutions settles on the bottom. It can readily by .- ^'1 of the liquid separated and the cooled by subsequent cooling, z. B. produced by filtration, decanting or concentrate. The dehydration can be centrifuged. The liquid then still adhering to the paraformaldehyde by the application of vacuum or by distillation can be carried out by evaporation, gelation with organic liquids, which may result in low-boiling azeotropic mixtures with water, if necessary in a stream of air or using low-boiling azeotropic mixtures, by vacuum, at low temperatures and at will. Other methods are used to remove the slightest loss of formaldehyde, with partial condensation of formaldehyde. After drying, the formaldehyde content of the steam is lower. io Paraformaldehyde between 85 and 95 weight-When this process is carried out in percent, mostly between 88 and 92 weight percent, of the first dehydration stage, a product is obtained Ver formaldehyde content is about 70 percent by weight and drive the products obtained by being dust-free, more is. The pre-concentrate is from 15 good flowability, high solubility and aging Pera doors, where it arises, through 7O ⁰ C, stability at the tem-. an easily mobile, depending on its formaldehyde- The following examples serve to illustrate the content is more or less clear melt. If invention, it is cooled to room temperature, then ice ο ie 1 1
one also obtains a 20 depending on the formaldehyde content more or less slightly viscous, gelatinous From a formaldehyde heated to 106 ° C to a solid opaque mass, but this mass cannot be pre-concentrate with a ·. Formaldehyde content can easily be melted again. 76 percent by weight were taken by means of a warmed-when the production of formaldehyde from the th siphon 107 g and this is carried out by a pre-concentrate in such a way that the further 25 nozzle, whose clear width was 1.1 mm and whose dewatering process to be carried out under An Wen - The opening is 4 cm above the liquid level where the dung is made at higher temperatures, the cooling liquid is in a thin stream and under this, greater formaldehyde losses occur. The moderate pressure in a beaker with 500 ml of benzene is also the case when the liquid pre-temperature of 22 ° C is introduced. The benzene, which concentrated in the process, as it warmed to 35 ° C in the manufacture of Paraform, was stirred vigorously. Due to the fact that aldehyde is common in flake form, over rotating moving liquid, the liquid jet was allowed to run in cooling rollers, on which the mass was torn into drops. Pearls formed, which solidified into a plastic film and then deposited on the floor after being scraped off. Immediately after termination can be. In US Pat. No. 2,704,765, the diameter of 0.4 to 1.5 mm was filtered off from the manufacture of paraformaldehyde by a process called benzene. After drying in the air, wrote that after a vaporous mixture was obtained 83.6 g of paraformaldehyde with a form of 60 to 90 percent by weight of formaldehyde with an aldehyde content of 90 percent by weight,
inert diluents, e.g. B. water vapor, ....
Methanol, methane and / or carbon oxides in a 40 J3 e 1 s ρ ι e 1 2
Organic liquid is introduced, which serves as a cooling, 21.5 g of a mold medium heated to 103 ° C and which contains as a condensation catalyst aldehyde preconcentrate with a formaldehyde, a basic or an acidic substance content of 80 percent by weight in weakly stirred. The paraformaldehyde falls in this case, petroleum ether 25 ° C (boiling range 80 to 100 ⁰ C) as a pasty mass in which 1.4 mm was the dry process must be subjected to even an intense 45 by means' of a nozzle whose inside diameter. And opening 12 cm above the liquid object of the invention is to find the disadvantages of the mirror, entered in a thin stream, to improve the known method, white pearls formed, which immediately settled on the bottom It has now been found that paraformaldehyde was deposited. The supernatant petroleum ether was poured off by cooling water-containing concentrated 50 and the pearls were dried.formaldehyde solutions can be obtained by using a 70-17.0 g paraformaldehyde with a formaldehyde to 85% by weight formaldehyde concentrate in a content of 88.5% by weight.
Shape of a thin beam into an opposite shape aldehyde inert organic liquid registered patent claims: which is in turbulent motion and 55 1. Process for the production of Paraform- whose temperature is at least 50 ° C below the temaldehyde by cooling water-containing, temperature of the melt to be entered is. The inven- concentrated formaldehyde solutions, thereby Paraformaldehyde produced according to the invention is characterized in that a 70 to 85 Obtained pearl form and has a high solubility weight percent formaldehyde concentrate in the form and responsiveness. 60 of a thin beam in an opposite shape The paraformaldehyde is thus introduced in the form of aldehyde-inert organic liquid get small pearls that the pre-concentrate is in, which is in turbulent motion thin stream, preferably at a moderate excess and its temperature at least 5O ⁰ C below pressure, in the stirred inert cooling liquid, the temperature of which is the melt to be introduced. Boiling point should preferably be below 120 ⁰ C, 65 2. The method according to claim 1, characterized in that is entered. The coolant used is that for the generation of the thin for example benzene, toluene, cyclohexane or petroleum jet a nozzle is used and the jet ether in question. The resulting paraformaldehyde escapes under moderate excess pressure.