SU969151A3 - Process for producing alkali metal or ammonium mono- or trichloroacetates - Google Patents

Abstract

The roller is for use in offset printing presses, to give an even film of liquid over the printing roller. Its entire surface has a degree of roughness which is constant or virtually so, lying between 7 and 16 micro-Rt or 1.8 and 2.5 micro-Ra. The design avoids the formation of dribble-type thickened areas of liquid dur to an excess having accumulated between printing and smoothing rollers. Ink built up on the moisturising roll and the friction roll is eliminated. Roughing of the roller which may have a chrome coating is generally done by an electrolytic process. Alternatively, a sand blasting process may be used.

Description

This invention relates to a process for the preparation of alkali metal or ammonium salts of mono- or trichloroacetic acids, which are widely used in the art. Numerous methods are known for the preparation of these salts, based on the neutralization of chlorinated acetic acids with corresponding bases. Pure acids in solid, molten or dissolved in hydrogen form, as well as hydroxides or carbonates of alkali or alkaline earth metals or ammonium compounds, are used as starting materials. Basic reagents are used in solid form, in the form of aqueous solutions or in the form of a suspension. At the same time, the reaction conditions are chosen in such a way that there is no further conversion of chloroacetic acid salts, since these compounds due to local overheating of the reaction mixture are easily subjected to pyrolysis, especially in the presence of water. In the presence of sufficient quantities of water at a higher temperature, the hydrolysis increases more and more. This is counteracted by adding a little water to the starting materials, water added and arising from neutralization and removal is carried out, the reaction temperature is kept as low as possible, and the contact time is short or the specified pH is maintained in an aqueous medium. A known method for the preparation of alkali metal and monochloroacetic acid salts by mixing crystalline or molten monochloroacetic acid with anhydrous alkali metal carbonate at. This produces the desired product and at the same time dehydrates. After 30 minutes of contacting the precursors of alkali metal chloroacetate with a water content of 1 wtCs and NaCl of 0.24 wt.% A method is also known for producing trichloroacetic acid by neutralizing free or carbonic, predominantly anhydrous bases with 88-94 wt.% Aqueous trichloroacetic acid. , and the pH of the primarily obtained crystals and mother liquor is mezkda b and 8, the resulting 94% anhydrous powdered sodium chloroacetate should have an apparent density (bulk density) 1 and should not have a slope After agglomeration, it is dried at 60 ° C and under reduced pressure and then turns into a powder 2.

In the known methods of obtaining a product in the form of a fine powder, it is prone to clumping, however, for better handling and easier solubility during processing, granularity and particle size distribution in the flowable properties of chloroacetic acid salts are very important.

The closest technical solution to the invention is a method of producing alkali metal or ammonium salts of mono- or trichloroacetic acids, in particular alkaline methanol chloroacetate, by neutralizing molten monochloroacetic acid; sodium hydroxide or water in concentrated solutions, suspensions, or in the form of fine powder, in the spray dryer at 80-220.

According to one of the examples, the soda is blown with air heated to 100 ° C and at the same time, molten monocharyoacetic acid heated to 80 ° C is fed through nozzles. The resulting Salt Contains 0.4 wt.% Cz chloride.

The disadvantage of this method is the low quality of the target product.

The purpose of the invention is to increase the purity of the target product.

. The goal is achieved by the method of obtaining alkali metal or ammonium salts of mono- or trichloroacetic acids by combining these acids with the corresponding salt-forming compounds, according to which water-borne carbonate or ammonia is used as salt-forming compounds, and the process is carried out at 20-120 0 in a boiling bed, formed from the resulting salt and inert gas stream or inert liquid, and the resulting desired product is continuously or periodically removed.

In this case, it is desirable to use mono- or trichloroacetic acid in the form of a solution or melt.

. - It is also desirable to use mono- or trichloroacetic acid in the form of a melt, which is introduced into the fluidized bed by means of an inert gas in the vapor state.

In addition, anhydrous carbonate salt is desirable to use in solid or dispersed form.

In this case, carbon tetrachloride is used as an inert liquid.

The quality of salts of chloroacetic acids is highly dependent on their purity and granularity. Products with a rather high water content and a high proportion of small particles are prone to agglomeration. But a slice of salt can be further processed only with difficulty, for example, it is very poorly soluble in water, although it is completely absorbed by water. This, due to the long time it takes to dissolve such lumps, leads to partial hydrolysis before the dissolution occurs. The consequence of this is a loss of yield with q Q products.

I Water content of flowable salts therefore should preferably be below 0.5 wt.%, The content of alkali metal, alkali metal or ammonium chloride, alkali or ammonium, preferably below 0.5 wt.%, Possibly below 0/2 wt.%. The spectrum of salt particles mainly should have the following composition,%:

 more than O, 40 mm 20; 0.40-0.20 mm 20. 40; 0.20-0.063 mm 50-70 and less than 0.063 mm less than 10.

FIG. 1-4 shows the apparatus for the implementation of the proposed method.

Example 1. {FIG. one). Obtaining sodium monochloroacetate in technical equipment (continuous mode of operation).

Into a fluidized bed (bale ohm) reactor 1 with a length of 4 m and a diameter

0 250 mm of glass or enamelled steel through a mesh bottom 2 serves air flow (approximately 40 m), which is blown through line 3 and heater 4. Approximately 12 kg of monochloroacetic sodium are used as fluidization material. The pipeline 5 serves 3.3 kg / h of liquid containing 20 wt.% Water, monochloroacetic acid and

spraying soda ash at an amount of 1.5 kg / h from collector 6 through transport screw 7 is fed to reactor 1. In a conically expanded to decrease the flow rate, a settling tank 8 precipitates a fraction of the fine fractions of the removed solid and returns to reactor 1, while the fraction of sakhsh fine fractions entrained in the air flow through pipe 9 is fed to the cyclone separator 10 and separated there. Exhaust gas (air, COi) leaves the apparatus through line 11. Collected in a cyclone separator 10 solid particles through a gateway

L2 is periodically added to 13 soda piped through the conduit. The fluidized bed reactor 1 is brought to the most favorable for the transformation of the reaction temperature, about 90 ° C. To measure the pressure and temperature, nozzles 14 are distributed over the entire length of the reactor I. The neutralization heat can be removed under known conditions through a heat exchanger 15, which is supplied with a heat transfer fluid by means of a circulation pipe 16 and a pump 17. The circulation pipe 16 also serves to heat the reaction components during commissioning (commissioning) of the installation. A refrigerator 18 is provided for heat removal, a heater 19 for supplying heat, which can be used selectively. Composed initially of preloaded soda and after about 4 hours of run-up time (without addition of soda) from the target product, the solid fluidized material (about 12 kg) has a temperature of about 90 ° C, which can be maintained thanks to the heat exchange system 15-19, and monitored by a temperature sensor 14 and maintained in motion with blown air. 3.2 kg / h of mono-chloroacetic sodium is continuously discharged through the discharge screw 20.

 Product HORSH1O is loose and has a bulk density of 0.82 kg / l, as well as the following particle size distribution,%: more than 0.5 mm 7.9; 0.5-0.315 wal 5.3; 0.315-0.2 mm 26.0; 0.2-0.063 mm 54.9 and less than 0.063 mm 5.9.

Approximately quantitative.

The composition of the product, wt.%: Sodium monochloroacetic acid about 99; sodium chloride 0.3; water 0.2; monochloroacetic acid 0.2 and pH 5.8.

Example 2: Preparation of sodium monochlorine chelate in laboratory equipment.

a) Periodic method of work (Fig. 2).

The test apparatus is equipped like the apparatus of Example 1 and as the main part contains a fluidized-bed reactor consisting of a jacket equipped with a jacket.1 of 1 m long glass with an inner diameter of 50 mm and a frit hollow as the bottom of the incident flow 2. Vioi The reactor 1 contains a conically expanded settler 3 for separating and returning the fraction of the fines to reactor 1. Through the additionally included dust separator 4, the fraction of the smallest fractions is discharged.

In order to periodically obtain monochloroacetic sodium, 410 g of anhydrous soda is preliminarily placed in reactor 1 and, at ZO-SOO C, a fluidized bed is created using 2.2 m- / h of nitrogen supplied through conduit 5 as nitrogen. From supported at BOM. collection 6 with 1150 g of molten monochloroacetic acid, which is fed through pipeline 3, is blown into the reactor 1 of its pair, together with the fluidizing gas. After about 8 hours, the conversion is completed; The fluidized material does not consist of soda anymore, and as a result of gradual transformation it consists of almost pure monochloroacetic sodium (850 g), which, under pressure of gaseous nitrogen, is extracted through

0 frits 2 nozzle (nipple) 8. 400 g of monochloroacetic acid remain as a residue in the collection.

b) Continuous mode of operation (Fig. 3).

five

For the continuous interaction of monochloroacetic acid with soda ash, you can use experimental equipment of such a type that in the upper part of the heated fluidized bed reactor 1 there is an inlet through which 40.g / h of soda from collection 3 is fed through the transport screw 2. At the same time

5, sodium monobasic acid (86 g / h) formed continuously through the discharge pipe 4 is continuously removed. 600-800 g of mono-sodium chloroacetic acid are used as the fluidized material, which can be obtained in the same apparatus as with the periodic method. The consumption of monochloroacetic acid from the collector is 73 g / h. Maximum

5, the reaction temperature is 120 ° C.

The resulting products are rather coarse-grained and well-flowable. Bulk weight

0 is about 0.8 kg / l, the particle size distribution of the slaves is di,%: more than 0.4 mm 11.7; 0.2-0.063 mm 59.9; 0.4-0.2 mm 26.2 and less than 0.063 mm 2.2.

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The outputs per monochloroacetic acid are approximately quantitative. For the target product, the following average composition is typical, wt.% :. sodium monochloroacetic acid 99;

0 sodium chloride is less than 0.2 and water is less than 0.1, pH 6.8.

Claims (5)

Example 3. (Fig. 4). Preparation of sodium monochloroacetate in suspension (periodic method). In a heated fluidized bed reactor 1 with a capacity of 2 liters with a side circulation pipe 2, there are 159 g of anhydrous soda, suspended in 1800 ml of tetrahydrate carbon. At 75-80 ° C, 285 g of molten monochloroacetic acid dissolved in 300 ml of carbon tetrachloride are added dropwise to this suspension over a period of 2–3 h, while simultaneously using pipeline 4, about 200 ml / h of carbon tetrachloride are distilled off. with it, the main part of the water formed during the reaction goes away, which, after condensation of the vapors in the refrigerator 5, is separated from the heavier specific gravity of tetrachloride from the lead through pipe 6. By metered return of carbon tetrachloride through line 7 to p 1 actor liquid level is maintained above the top of the circus l insulating conduit 2. The steam (and water.) and the reaction tavshy, flue gas (CO) is maintained TSIR molecules tion and at the same fluidized bed in liquid phase. The exhaust gas is discharged through pipework 8. To further transform, for another 2 hours, 200 ml of carbon tetrachloride are distilled off while leveling off the losses by returning the condensate. The suspension is then discharged through the outlet 9. After separating carbon tetrachloride and drying, 348 g of sodium monochloroacetic acid are obtained; the yield is 99%. The product contains O, 2 wt.% Sodium chloride and 0.1 wt.% Water, and is well flowable. The bulk density is about 0.4 kg / l. As a particle size distribution, the following values, on average, are determined:%: more than 0.4 mm; 14.5; 0.4-0.2 mm 34.3 0.2-0.063 mm 50.8 and less than 0.0063 mm 0.4. Example 4 (Fig. 4). Preparation of potassium trichloroacetate (periodic method); Analogously to example 3, using the one shown in FIG. 4 devices 69 g of potash of carbon tetrachloride suspended in 1800 mts, are brought into contact with 170 g of trichloroacetic acid dissolved in 300 ml. carbon tetrachloride, at 50-80 ° C. After separating carbon tetrachloride and drying, 191 g of potassium trichloroacetic acid are obtained, the yield is about 95%. The product is basic because it has an alkaline reaction (pH 9.2), it also contains 0.5% by weight of potassium carbonate, as well as less Q, l% by weight of potassium chloride and traces of water. The bulk density and particle size distribution is similar to that of Example 3. Example 5. Production of ammonium monochloroacetate (continuous method). If the apparatus (Fig. 4) is provided with a bottom with a tube for inlet gas, it is also suitable for producing ammonium salts of chloroacetic acid. In order to obtain ammonium monochloroacetate, 220 g of this compound is suspended (2 liters of carbon tetrachloride are drawn into the reactor 1. 30 l / h of NHj is continuously passed into this suspension at 20-50 ° C and 95 g are added dropwise through the nozzle 3 hourly at a time molten monochloroacetic acid dissolved in 1 liter of preheated carbon tetrachloride, while the appropriate amount of the salt suspension is discharged from the apparatus through the outlet 9. After the ammonium monochloroacetate is discharged, filter out and dry approximately qualitative, because excess ammonia is returned. A well-flowing product contains less than 0.1 wt.% ammonium chloride. By bulk density and grain size, ammonium monochloroacetate is comparable to sodium monochloroacetate from example 3. The particle size is within the following%,: more than 0.40 mmu less than 20} 0.40-0.20 mm 20-40; 0.200, 063 mm 50-70 and less than 0.063 mm less than 10. Claims of the invention 1. Method of obtaining alkali metal salts or ammonium mono- or trichloroacetic acids by interacting these sour t with the corresponding salt-forming compounds, such as the fact that, in order to increase the purity of the target product, anhydrous carbonate salt or ammonia is used as the compound of these compounds and the process is carried out at 20-120 ° C in a fluidized bed formed from salt and inert gas stream or inert liquid, and the resulting target product is continuously removed periodically. 2. The method according to claim 1, about t l. And h and y and the fact that mono - or trichloroacetic acid is used in the form of a solution or melt. 3. A method according to claim 1, characterized in that the mono- or trichloroacetic acid) is used in the melt that is introduced into the bale (the scientific research institute is a layer using an inert gas in vapor form. 4. Method POP.1, about tl and cha yu and with the fact that anhydrous carbonate salt is used in solid or dispersed form. 5. The method according to Clause 1 of tl and h a y i. and with the use of carbon tetrachloride as an inert liquid. Information sources taken into account by the expert 1. The patent of Germany 871890, CP. 120, 12, pub. 1953. 2. The patent of Germany 1113450, st. 120 12, published. 1962. 3.Patent UK  782479, class 2/3 / s, publ. 1957 (prototype). / P Fs & / J x -tz V yk2