CS229961B1 - Method of anti-caking treatment of hexamethylenetetramine - Google Patents

Abstract

The invention provides a technically simple method for producing non-sintering hexamethylenetetramine by utilizing an available additive, the content of which is chosen such that the agglomeration tendency decreases or decreases. complete suppresses. SUMMARY OF THE INVENTION The present invention is based on the addition of a disposable or sequential tetrahydroimidazo [4,5-d] imidazole-2,5- (1 H, 1, 2, 3) to hexamethylenetetramine either in the solid phase and / or in an aqueous medium, preferably to crystalline hexamethylenetetramine. 3H-dione in an amount of 0.1 to 50% by weight, preferably 20 to 50% by weight, calculated on the solid phase and after homogenization! the product is further processed.

Description

The invention solves a technically simple epdeob for producing non-volatile hexemethylenetetramine by using an available additive, the content of which is selected such that the tendency of agglomeration ea decreases or completely suppresses.

Hexamethylenetetramine has a wide industrial application After its manufacture and before use, it is usually stored in bags, possibly in containers or containers. In the case of pure hexamethylenetetremine, it is observed during such storage of the agglomeration, or conspiracy, and in such a way that the stored material is converted to a relatively non-solid mass, e.g. in the form of agglomerated lumps, as opposed to the desired bulk material.

This undesirable property epdeobes hardly in the β mechanical operations of the substance, whether as an intermediate or final product.

The degree of sintering is determined by the factors, but most often the moisture content / internal. outside temperature, its storage temperature and its colleanlm. the pressure under which the product is stored, the storage time, the size of the particles (crystals) and their shape, and the like.

It considers indoor and outdoor humidity to be the most important factor ea. The obtained hexamethyl-tetramine crystal has, after leaving the oven, an internal moisture content which depends on the drying method used. Upon rising the water to the surface, it provides saturated solutions, which are either the first phase to cause ala * 3 crystal sweeping.

229 981 boil on capillary adhesion · External humidity occurs when critical relative humidity is exceeded when absorption occurs! moisture, which is associated with the dissolution of the surface return of the crystals to form a saturated solution and later, when the humidity decreases, it evaporates and the crystals evaporate, t, J, hexamethylenetetramine lump · It is necessary to mention that the water absorption rate such as crystal size and surface, diffusion and adsorption processes, system air exchange, and the like

Storage temperature has an effect on the agglomeration at least because by increasing it the proportion or rate of a number of chemical reactions that contribute to the agglomeration. The pressure below which hexamethylenetetramine is stored contributes to the agglomeration with a view to improving the perfect surface or surface area. in case of possible deformation of the crystals, the contact area will also increase ·

Storage time is associated, as is evident, with decomposition reactions the rate of which corresponds to the re-tempering temperature, and agglomeration occurs within a relatively short period of up to 10 days. In contrast, dissolution and recrystallization cycles require a longer time to agglomerate but exhibit · On the other hand, attractive capillary forces can be created quickly. · The solution does not saturate very quickly, only by exchange of moisture and air, by the length of the cup, especially under pressure, the contact surfaces of the crystals are modified as mentioned above.

The crystal size is also a significant factor, especially when the product contains a fine particle fraction, which obviously promotes agglomeration ·

The design of a suitable sintering mechanism for hexamethylenetetramine is very difficult in view of the existence of it. a wide variation in the physical and chemical properties of the surfaces, which is evident from the foregoing interpretation.

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Simplified explanation of the mechanism It is such that, due to adeorbed moisture, a saturated solution forms on the surface of the crystals, which, due to capillary forces, accumulates on the crystals of the crystals. clusters. Under the influence of external conditions advantageous for the crystallization of hexamethylenetetramine from saturated solutions forming liquid bridges, recrystallization occurs and agglomeration or agglomeration of the formed agglomerates occurs.

This dual view is built on the theory of crystal stiffening and cepillary adhesion, which have survived much discussion and criticism.

Much can be done to zebréati apekavoati in the design of the production unit, it is also important selection of raw materials and auxiliary drugs, as well as methods of their processing, one of the obvious procedures to prevent caking would be a cracking of good crystals in a clean atmosphere and prevent outside air This condition, however, is practically impractical for operational reasons. SalSim is a process that can be used to suppress sintering by drying the hot product and cooling it quickly before packaging it.

However, in practice, in the case of hexamethylenetetramine, it is always necessary to use a kind of additive for ultimate protection. It would be accepted by manufacturers of hexamethylenetetramine to wear this necessity, but at present it seems impossible,

Research into the use of various additives can be divided into two groups. The first group includes substances which are capable of adsorbing or absorbing moisture while reducing the number of contacts between the crystals of hexamethylenetetramine, mainly by inert types of anti-agglomeration powders characterized by fineness and high specific surface area. After their application in the required amount

- 5 229 991 will cover the individual crystals of hexamethylantetramine · Since they do not form a continuous lernert film around the crystal, therefore the process leading to the phiopia agglomeration continues to modify the structure of the intercrystalline bond during the solvent-crystallization cycle, which is what! · They also absorb large amounts of saturated solutions and thus absorb capillary ails · violet may act as moisture regulators to some extent and inhibit its exchange · The most important physical swelling agents of the anti-caking agents of this group are granulometry, particle shape or crystal shape and its structure ·

The saleric group consists mainly of tenzoactive and waterproof cover forming a hydrophobic film on the crystalline mass of haxamethylantetramine protecting the area at least away from water access ·

The use of various modified silica oxides / V is known from the available literature. Brit * pat · 1 014 904 / ala also mineral acid salts such as sulphates and phosphates 8 with methanol / Japanese pat · 74 - 20200 / · Silicone oils, boron containing substances such as boric oxide, boric acid, borates were also tested with good results and the application of substances from the group of dyes violet was also successful, and the use of an emulsion of acetic acid and nonionic surfactant / MS was also to be considered. U.S. Pat. No. 121,974], benzoic acid and derivatives thereof (U.S. Pat. No. 1,382,616), U.S. Pat.

912 435, V, Brit · pat, 810 765 /, calcium ataaran, magnesium ataaran / V, Brit. pat · 1 014 904, french · pat ·

382 815), further monoeulfonated aromatic compounds (cs. 205 611 / · Great advantages are achieved by the eortiment of anti-volatile ingredients, in accordance with author's certificate 205 440, e.g. alcohol, etc. ·

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Currently ea is paying special attention to the treatment of haxamethylenetetramine with substances with the same chemical entity * Such substances include water-insoluble urea-formaldehyde condensates / MS * author's certificate

The treated product in the sense of the present invention is usable without risk in the production of cyclic nitramines * which cannot be said of the said treated products *

According to the invention, the antispasmodic treatment of haxamethylenetetramine is carried out by adding to the hexamethylenetetramine either in the solid phase and / or in an aqueous medium, preferably to the crystalline hexamethylenetetramine * a single or sequential tetrahydroimidazo [4,5-d] imidazole2. 5- (1H * 3H) -dione in an amount of 0 * 1 to 50% by weight ** preferably 20 to 30% by weight ** calculated on the solid phase and after homogenization the product is further processed *

The advantage of the antispasmodic treatment of hexamstylenetetramine according to the invention is the fact that it is obtained a product replacing commercially types of hexamstylenetetramine * which has a low ash content and does not have a lump-forming tendency * for the manufacture of cyclic nitramines * in the plastics and rubber industries, etc. *

Tatrahydroimidazo [4 * 5-d] imidazole-2 * 5 (1H * 3H) dione alone finds widespread use in chemical technology as a component for the manufacture of fabric conditioning products * as a raw material for the synthesis of psychopharmaceuticals * explosives * deodorants in blowing agents and so on furthermore, the prospective availability of this substance and the possibilities for its use in the products of the present invention are proven * Apply tetrahydroimidazoate * 5-d / imidazole-2 * 5 (1H * 3H) -dione by wet or dry method * Tetrahydroimidazo / 4 * 5-d] imidazole-2 * 5H-1H * 3H Dione, in addition to its anti-caking effect, also manifests itself under certain conditions

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Known anti-caking agents are salts of mineral acids such as nitrates, sulphates and the like, urea-formaldehyde condensates, surfactants.

The invention is illustrated but not limited by the following examples.

Example 1

Hexamethylenetetramine is introduced into the homogenization apparatus and some tetrahydroimidazo [4,5-d] imidazole-2,5 (1H, 3H) -dione (glycoluril) is added thereto. After 30 minutes of homogenization, the mixture is packed into bags with a polyethylene liner after a. The bags are placed on pallets of about 30 kues and are thus stored 180 times at 20 to 24 ° C. After this time, the product is sintered.

The results are presented in the table:

Sample Hexamethylene tetramine with glycoluril obeah /% w / After storage 0 agglomeration perfect, compact piece 0.47 softened / once disintegrated into a rat- 1.03 melts and tiny spreadable lumps 4.85 a loose, slight hint of agglomeration 20.00 loose 50.00 loose

EXAMPLE

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Hexamethyleneteteamine 8 containing 0.1 wt. % insoluble urea-formaldehyde condensate and 0.5 wt. glycoluril, after 30 minutes homogenization, mix in bags with polyethylene liner of 25 kg · Bags are stored on pallets of about 30 pieces and thus cooled for 180 days at 20 to 24 ° C · After storage time control product is loose , no hint of agglomeration ·

Claims (1)

OBJECT OF THE INVENTION 229 961 A method of anti-caking of hexanethylenetetramine, characterized in that the hexamethylenetetramine is either a crystalline phase and / or a cocrystalline hexamethyltetramine, or a single tetrahydroimidazole / 4 # 5-d / imidazole-2,5. «(1H, 3H) -dione in an amount of 0.1 to 50% by weight, preferably 20 to 30% by weight, calculated on the solid phase and after further heating the product is further processed.