CS245072B1 - 1,2-ethane-bis-dithiocarbamic acid's salts' aqueous solutions' 11 till 66 per cents preparation method - Google Patents

Description

The invention relates to a process for the preparation of aqueous solutions of 1,2-ethane-bis-dithiocarbamic acid salts.

Water-soluble salts of substituted dithiocarbamic acids are important intermediates and products of the chemical industry. They are based on the production of several agrochemicals - fungicides, fragrance disinfectants, seed dressings and nitrification inhibitors; cotton fungicides; rubber chemicals; drugs; metal microbial corrosion inhibitors; chemical analytical reagents and the like.

Water-soluble salts of substituted dithiocarbamic acids are usually prepared by reacting carbon disulfide with alkanediamines or dialcanamines in an alkaline medium.

Conventional procedures for the preparation of water-soluble salts of alkylenebisdithiocarbamic acids have been based on the reaction of carbon disulphide with alkanediamines in a strong alkaline environment. According to processes of this kind, for example, the disodium salt of ethanebisdithiocarbamic acid was prepared by adding carbon disulfide to a mixture of 1,2-ethanediamine and aqueous NaOH with stirring. Processes of this kind are commonly referred to as " strongly alkaline " and are protected by a variety of patents and copyright certificates, including the following: U.S. Patents Nos. 2,317,765 and 2,504,404, U.S. Pat. AO No. 197 196. As disclosed in U.S. Patent No. 2,693,485, French Patent No. 1,158,574, Germany Patent No. 1081,446 and ZAVIZION et al. (Chim. Prom. 3, pp. 174-175 (1972)) The water-soluble salts of bisdithiocarbamic acids prepared by these "strongly alkaline" processes are usually characterized by low purity - they contain several by-products contaminating the main product, the desired product yields being low, aqueous solutions the alkali salts are relatively unstable, the solid - crystalline products isolated from the reaction mixture upon cooling do not readily dissolve in water, the solutions usually smell strongly of the releasing hydrogen sulfide and also contain thiocarbonates.

U.S. Patent No. 2,693,485 also discloses that the fungicides prepared in this manner tend to be phytotoxic, reducing their agrochemical value.

A more recent and considerably improved process for the preparation of water-soluble, in particular sodium, alkylene bis-dithiocarbamic acids is protected by U.S. Patent No. 2,609,389. This method of preparation is the opposite of the so-called " strongly alkaline " Accordingly, the corresponding alkanediamine (e.g., 1,2-ethanediamine) reacts first with carbon disulphide to produce an intermediate which is reacted with the appropriate hydroxide solution in the next step. Although this process presents some improvement, especially when it comes to the formation of unwanted intermediates, stability and its phytotoxicity does not sufficiently prevent the formation of by-products which the presence in aqueous solutions of alkylenebisdithiocarbamic acids can be deduced from because of the dark orange color of the solution and also because solutions (mainly sodium and potassium salts) usually smell relatively strongly of hydrogen sulphide.

The effect of the basic reaction conditions on the yield and purity of the 1,2-ethane-bis-dithiocarbamic acid diammonium salt prepared by U.S. Pat. No. 2,609,389 has been studied in detail by, for example, ZAVIZION and co-workers (Chim. Prom. 1972/3 / pp. 174-175.

In order to suppress the formation of unwanted by-products, GOBELL (U.S. Pat. No. 2,693,485) proposed to prepare the desired water-soluble metal salt of alkylenebisdithiocarbamic acid by a batch process so as to maintain the pH of the reaction mixture in the range of 8.5 to 11.0. The aqueous solutions of the disodium salt of 1,2-ethanebisdithiocarbamic acid prepared in this manner contain only a very small amount of undesirable pollutants, are light in color and only very slightly or generally do not smell of hydrogen sulfide. Likewise, hydrogen sulfide is not released from the reaction mixture during the reaction.

Reaction mechanism of alkylene bisdithiocarbamic acids, respectively. their salts is not yet fully understood. ZAVIZION and co-workers assume the following reaction mechanism in the preparation of the 1,2-ethanebisdithiocarbamic acid diammonium salt:

CS2

ΝΉ2. (CH 2) 2. NH2 -> NH2 (CH2) 2NHCSSH -> (II) nh ^ (ch ^ ₂

----> NH3 (CH2) 2NHCSS ---- ► (I)

NH3 CS2

----> NH 2 (CH 2) 2 NHCSSNH 4 ---->

CS2 NH3

I ----> HSSCNH (CH 2) 2 NHCSSNH 4 ---->

NH 3 + - _ +

----> NH 4 SSCN (CH 2) 2 NHCSSNH 4.

(Π)

A similar procedure explains the formation of ammonium 1,2-ethane-bis-dithiocarbamate HOLAN and HINDE (Australian Patent No. 237,152). In accordance with the above reaction scheme, the second amino group of 1,2-ethanediamine (ethylenediamine j does not react with carbon disulfide in neutral environment) can be assumed (JAKUBOVIC, A.J. - KLIMOVA, VA: W. Obs. Chim. 1939, 9, p. THORN and LUDVIG (The Dithiocarbamide over Relatide Compounds. Amsterdam - New York, 1962) report that the intermediate - (3-aminoethylenedithiocarbamic acid (I) forms the ethylenediamine inner salt of this type (III) under the following conditions:

ch, nhcss / 5h, ch

I - ₊ I ch ₂ nhcssnh ₃ ch, ("/)"

Compound (I) can be a source of a variety of by-products. For example, ZAVIZION et al. (Chim. Prom. 1972, 3, pp. 174-175) and SCHROEDER (Chem. Rev. 1955, 55, p. 181) report that its decomposition product is ethylene thiourea (ETU) and hydrogen sulfide:

> H 2 S t CH ₂ -NH 1 os ετυ

The oxidation of ETU can then give 2-imidolidolidethyleneaurea, 2-imidazoline (4,5-dihydroimidazole) in the system:

O

II ^Ct -t—

2-imidazolidone

2-imidazoline (MARSHAL, WD - SINGH, J .: J. Agric. Food Chem. 1977, 25, 1 316-1 1320; NEWSOME, WH: Ethylenebisdithioacarbamates and Their Degradation Products. Analytical Methods for Pesticides and Plant Growth Regulators, Vol. XI, Academic Press, Inc, 1980, pp. 197).

Depending on the reaction conditions, some other reactions may also occur in the system of interest in addition to the desired reaction. For example, ammonium hydroxide on carbon disulfide gives rise to red solutions from which, as reported in the literature, orange and lime crystals of the carbonate - (NH4) 2CS3 and (NH4) 2CS4 (COTTON, FA - WILKINSON. G .: Inorganic Chemistry, Prague, Academia 1973, p. 316). Thiocarbonates in alkaline environment sa

CH «NHCSS 'i ^Z jc ^! by WERTHEIM, GATTOWA and HAHNKAMMA (J. Am. Chem. Soc., 1926, 48, p. 826; Z. anorg. allgem. Chem. 1969, 364, p. 161; ibid. 1969, 365, p. 70) decompose into sulphides and rodanides.

Thiocarbonates also decompose under the action of atmospheric oxygen, which can be schematically represented as follows:

Na2CS3 - Na2S + CS2

Na 2 S + H 2 O -> NaSH + NaOH

2NaSH + O -> Na 2 S 2 + H 2 O

Na2S2 + 3 O-> Na2S2O3

The formation of thiocarbonates is supported by the temperature and action of the free alkali (also in the case of local pre-alkalization).

Also, alkylene bisdithiocarbamates themselves are relatively poorly stable (THORN, G. D - LUDWIG, RA: Can. J. Chem. 1954, 32, pp. 872-879; LUDWIG, RA - THORN, GD - UNIN, CH: Can. J. Bot 1955, 33 pp. 42-59 (CZEGLEDI-JANKO, G .: J. Chromatogr. 1967, 31, 89-95).

ZAVIZION and Collaborators (Chim. Prom. 1972, 3, pp. 174-5) report that the oxidation of the 1,2-ethane-bis-dithiocarbamic acid bivalent ammonium salt may produce the following products:

CK ₂ NHCS _x ch ₂ nhcs ^x

CH »NH

S + S-> OS-hCS ₂

1,2-Ethanebis-thiuram disulfide (ethylenebistiuram disulfide)

1,2-ethanediurammonosulfide

When aqueous solutions of alkali metal dialkedithiocarbamates are treated with oxidizing agents such as Cl ² , J ² , S ² O ^{8 2} ', (Fe) CN (e) ³ ' or H 2 O 2, tiuram disulfides are obtained (COTTON, FA —WILKINSON, G .: Inorganic chemistry, Prague, Academia 1973):

R2 NCS2 - + J2 ->

-> R2N — C — S — S — C — NR2 + 2 µL; if

S p

Thiuram disulfides provide by heating free radicals that can act as initiators of further reactions.

As already seen, in order to limit the formation of by-products in the preparation of alkene bis-dithiocarbamic acid salts, it is necessary, while maintaining optimal ratios between the reacting components and optimal temperature ratios, to maintain optimal pH ratios of the reaction mixture. . locally achieving extreme pH values in the reaction mixture.

In this connection it should also be noted that, for example, during the preparation of an approximately 20% aqueous solution of 1,2-ethane-bis-dithiocarbamic acid, a bivalent ammonium salt according to the procedure of FLENNER (U.S. Pat. No. 2,609,389) and ZAVIZINA (Chim. Prom. 1972, 3, pp. 174-5], monitoring the pH of the reaction mixture revealed that the pH of the undiluted reaction mixture varied between 3.9 and 10.4 during the study.

Similarly, only after repeated experimentation and only with the special attention of the experimenter, was it possible to maintain the pH changes of the reaction mixture within the prescribed limits by controlled dosing of the reactants even during reproduction of the procedure proposed by GOBELL. - example 4).

Virtually all of the production methods mentioned in the scientific and patent literature relate only to batch-led production processes. The exception is the continuous process for producing dithiocarbamates protected by the NSR Pat. No. 1118,186 and U.S. Pat. No. 3 210 409, based on the reaction of carbon disulphide in the vapor phase (at a temperature above the boiling point of CS2) with a solution of one or more amines, at atmospheric or slightly elevated pressure (0.1 to 0.6 MPa), in a filler This process allows to shorten the reaction time considerably, but we use it in practice it assumes the construction of a special and relatively complicated high-volume machinery, while the production process only partially eliminates the possibility of reaching extreme pH values in the reaction mixture.

It has now been found that most of the drawbacks of the previously described processes can be overcome by preparing 11 to 66 percent aqueous solutions of 1,2-ethane-bis-dithiocarbamic acid ammonium, sodium, potassium or magnesium by reacting 1,2-ethanediamine with carbon disulphide and ammonia, sodium or potassium hydroxide or carbonate, or with magnesium oxide, hydroxide or carbonate in an aqueous medium, at a temperature of 20 to 60 ° C and at a pH of 6.0 to 13.0, the reaction product optionally being stabilized. The principle of the invention is that 1,2-ethanediamine, carbon disulphide and the corresponding alkali are simultaneously fed into the reactants, with 1 mole of 1,2-ethanediamine in the reaction medium accounting for 2.01 to 2.35 moles of carbon disulphide and 1.95 to 2.40 moles of ammonia, sodium hydroxide or potassium hydroxide, or 0.98 to 1.27 moles of sodium carbonate or potassium carbonate, or 0.98 to 1.90 moles of magnesium bicarbonate, magnesium carbonate, hydroxide or magnesium oxide, reaction medium contains 34 to 89% by weight of water, the mean residence time of the reaction mixture in the reaction medium is 9.0.10 ² to 21.6.10 ³ seconds, the mixing intensity of the reaction mixture in the reaction medium being characterized by the Reynolds criterion value for stirring Re _M , that:

₌ ZLlb P _, i ₃ . _w3j

Η η where

Re _M is the Reynolds criterion for mixing,

K is a coefficient dependent and velocity distribution in the annular cross section between the vessel wall and the stirrer, n is the stirrer speed (s ^_1)

D is the vessel prierner (m), d is the stirrer diameter (m), p is the density of the reaction mixture in the reaction medium (kg. M ~ ³ ], η is the dynamic viscosity coefficient of the reaction mixture in the reaction medium (kg. Nr ¹⁾ . s ^1), and for the input of N agitator per unit volume of the reaction mixture stirred, the 10 ² <N / V <10 ³ kg. m ^_1. s ^-3, wherein the unreacted carbon disulfide was removed from the reaction mixture.

It has also been found to be advantageous if the carbon disulphide and 1,2-ethanediamine, and optionally the corresponding alkali, are dosed below the level of the reaction mixture in the reaction medium.

It has proven advantageous to select the power input of the reaction mixer used in the reaction medium, with the power input of the stirrer N per unit volume of the reaction mixture stirrer in reaction medium V being 200 <N / V <800.

Furthermore, it has also been found to be advantageous if the unreacted carbon disulphide is removed from the reaction mixture by evaporation.

It has also been found that in accordance with the statements of HOLAN and HINDE (Australian Patent No. 237,152), FLENNER (US Pat. No. 2,609,389) and ZAVIZION and coworkers (Chim. Prom. 1972, 3, pp. 174-175). ], even under the conditions of continuous conduction of the process for the preparation of the water-soluble salts of 1,2-ethane-bis-dithiocarbamic acid, carbon disulfide is preferred and

The 1,2-ethanediamine is mixed before it is fed into the reaction medium, and it can be assumed that the two components will form as an intermediate by mutual reaction _; S-aminoethylenedithiocarbamic acid.

It has also been experimentally confirmed that the optimum pH of the reaction mixture maintained during the continuous preparation of the 1,2-ethane-bis-dithiocarbamic acid water-soluble salts according to the invention is close to the pH of the aqueous solution of the respective 1,2-ethane-bis-dithiocarbamic acid water-soluble salt.

Especially if the reaction product - aqueous ammonium, sodium, potassium or magnesium salt of 1,2-ethane-bis-dithiocarbamic acid is not immediately further processed, it is expedient to stabilize it by adding hexamethylenetetramine, methanol, or paraformaldehyde and / or in storage the product container to maintain a protective layer of inert gas, optionally a protective layer of liquid that is inert to and not mixed with the product.

The following examples illustrate but do not limit the scope of the invention.

Example 1

For the laboratory study of a continuous process for preparing a 30% aqueous solution of ammonium 1,2-ethane-bis-dithiocarbamate according to the invention, an all-glass apparatus consisting of two cascaded glass stirred reactors was constructed, each having a total volume of 1,500 cm ³ ( working volume determined by the height of the side overflow of the reaction mixture: 1 200 cm ³ ).

The reactors had a diameter of 120 mm, the diameter of the double-blade glass stirrer coaxially installed in each of the reactors was 55 mm. The stirrers were driven by electric motors with a set stirrer rotation speed of 400 rpm.

. min “ ¹ . Both reactors were placed in a water tempering bath whose temperature varied between 38 and 42 ° C. The first of the reactor cascade members was further provided with a poor water cooler through which the reactor was ventilated and also the distilled water supply to the reaction system, with a short packing column that served as a gravitational static mixer dosed with 1,2-ethanediamine (ethylenediamine). with carbon disulphide before they enter the reactor of the ammonia water feed downstream of the reaction mixture in the reactor with an electrode pair (glass and saturated kaloinel electrodes serving for continuous pH recording of the reaction mixture and a glass mercury thermometer).

The above reactor was coupled to the reactor by means of a side overflow of the reaction mixture

Re _M ___ n. d (D-d). p

K '.....' p

During a long-term continuous experiment, an average of about 0.8 kg of a bright yellow ammonium 1,2-ethane-bis-dithiocarbamate solution was obtained per hour, which, as a result of the chemical analysis of the averaged product sample, contained 29.6 wt. % of active substance. The density of the prepared aqueous solution at 20 ° C was 1099.4 kg. m ^-3 . Its dynamic viscosity was 13.10 ^-3 kg. m ^-1 .

. s ^-1 . The pH of the undiluted reaction product was 8.9.

Example 2

During this experiment, the laboratory apparatus specified in Example 1 tested the continuous process for preparing an approximately 20% aqueous solution of magnesium 1,2-ethane-bis-dithiocarbamate within the meaning of the invention.

second member of the reactor cascade. The second stirred reactor was equipped with an inverted condenser for vapor condensation and aeration of the reactor, supplying about 10% aqueous hexamethylenetetramine-urotropin solution, a glass mercury thermometer, and a side overflow to continuously evacuate the crude reaction mixture by gravity through the heat exchanger shutter. . The tube heat exchanger was placed at an angle and served to continuously remove the unreacted carbon disulfide residue from the crude reaction mixture by evaporating it. This was connected to a hot-water thermostat, being tempered to 55 ° C and thus acting as a continuously operating film evaporator.

An average static column mixer of 43.22 was fed into the first reactor cascade member using peristaltic (tubular) pump pumps from glass containers placed on the balance. 10 ³ g. with ¹ chemically purified and distilled CS2 and 16,08.10 · gs ^{-1 of} distilled 1,2-ethanediamine (ethylenediamine) and an average of 49.25. 10 ³ g. With ¹ ammonia water containing 18.72% NH 3 and 93.67.10 ^-3 gs ^-1 distilled water. Under these conditions and at steady state, an average of 202.22 overflows from the first to the second reactor cascade members.

. 10 ^-3 g. s ^{-1 of the} reaction mixture. On average, 22.22 was fed to the second reactor.

. 10 ^-3 gs ^{-1 of an} aqueous 10% solution of hexamethylenetetramine - urotropin. The average residence time of the reaction mixture in the first reactor was 6,524 seconds and in the second 5,878 seconds. The Reynolds criterion for mixing was equal to the following continuous run conditions in the two reactor cascade members:

6,67.0,055. (0.12-0.055) .1099.4

0.013

-2 016.6.

An average of 25.28.10 ^-3 g was continuously fed into the first stirred reactor. s ^-1 chemically pretreated and distilled carbon disulphide, 9,42.10 ^-3 g. s ^{-1 of} distilled 1,2-ethanediamine (ethylenediamine J and 0.1505 g s ^{-1 of a} homogeneous aqueous suspension of active MgO containing 4.32 wt% MgO. Under these conditions, the average residence time of the reaction mixture in each of the stirred reactor cascade members was 7 128 seconds, moreover, the reaction conditions maintained during this experiment were similar to those of Example 1.

During this multi-hour continuous experiment, an average of 667 g of product was obtained per hour as an almost clear liquid of light yellow color. Chemical analysis of the averaged product sample revealed that it contained 21.08 wt. % of the active substance. The undiluted product had a pH of 8.68.

Example 3

In order to prepare crystalline sodium 1,2-ethane-bis-dithiocarbamate hexahydrate according to the process of the invention, an all-glass apparatus consisting of two cascaded glass stirred reactors was used. The apparatus used was further specified in Example 1. Both reactors were placed in a water tempering bath whose temperature during the experiment varied from 39 to 44 ° C.

An average of 87.47.10 ^-3 g was fed to the first reactor cascade member using peristaltic metering pumps from containers placed on the scales. with ^-1 aqueous 40,5% solution of 1,2-ethanediamine (ethylenediamine), 95,14.10 ^-3 gs ^{-1 of} chemically purified and distilled carbon disulphide and 95,17.10 ^-3 gs ^{-1 of} 50% aqueous sodium hydroxide solution . Under these conditions, an average of 277.78.10 ^{-3 of the} reaction mixture flowed from the first to the second reactor cascade members. In the first stirred reactor, the pH of the reaction mixture was between 9.4 and 12.3 during a 6-hour continuous run of the apparatus, and its temperature varied between 40 and 44 ° C.

Approximately 6 kg of the crude reaction mixture was thus prepared in a 6-hour experiment, from which the unreacted carbon disulfide was removed by briefly heating to 55 ° C (by flowing the crude reaction mixture over the tempered wall). As a result of the evaporation of CS2, the pH of the reaction mixture decreased from an initial value of 12.0 to 9.7. An aqueous solution of sodium 1,2-ethane-bis-dithiocarbamate was prepared as described above.

Cooling the reaction mixture thus obtained. at 30 ° C, crystalline sodium 1,2-ethane-bis-dithiocarbamate crystallized out. The dried crystalline product represented about 60 wt. % by weight of the crude reaction mixture, which was found to contain 35.9 wt. % S and 8.04 wt. % N.

Claims (3)

1. A process for preparing 11-66% aqueous solutions of 1,2-ethane-bis-dithiocarbamic acid salts of the ammonium, sodium, potassium or magnesium salts by reacting 1,2-ethanediamine with carbon disulphide and ammonia, sodium hydroxide or carbonate, or potassium, or with magnesium oxide, hydroxide or carbonate in an aqueous medium, at a temperature of 20 to 60 ° C and a pH of 6.0 to 13.0, wherein the reaction product is optionally stabilized, characterized in that 1,2-ethanediamine, the carbon disulphide and the corresponding alkali are simultaneously fed into a reaction medium consisting of a mixture of product, intermediates and reagents, with 1 mole of ethylenediamine in the reaction medium comprising 2.01 to 2.35 moles of carbon disulphide and 1.95 to 2.40 moles of ammonia, sodium hydroxide or potassium hydroxide, sodium bicarbonate or potassium bicarbonate, or 0.98 to 1.27 moles of sodium carbonate or potassium carbonate, and or 0.98 to 1.90 moles of magnesium bicarbonate, magnesium carbonate, hydroxide or magnesium oxide, the reaction medium contains 34 to 89% water, the mean residence time of the reaction mixture in the reaction medium is 9.0.10 ² to 21.6. . 10 ³ seconds, wherein the stirring intensity of the reaction mixture in the reaction medium is characterized by the Reynolds criterion value Rc _m , for which the relation: Re _M iv. d_. (D-d). p> 1.3. 10 ³ INVENTION where Re _M is the Reynolds criterion for mixing, K is a coefficient dependent on the speed distribution in the annular cross section between the vessel wall and the stirrer, n is the rotational speed of the stirrer (s ^-1 ), D is the vessel diameter (m), d is the stirrer diameter (m), p is the density of the reaction mixture in the reaction medium (kg. M ^-3 ), η is the dynamic viscosity coefficient of the reaction mixture in the reaction medium (kg.m ^-1) . s ^-1 ), and for the power input of the stirrer N used per unit volume of the stirred reaction mixture V, 10 ² <N / V <10 ³ kg.m ^-1 .s ^-3 , with unreacted carbon disulphide being removed from the reaction mixture. 2. The process according to claim 1, wherein the carbon disulphide and 1,2-ethanediamine and optionally the corresponding alkali are metered below the level of the reaction mixture in the reaction medium. 3. The process according to claim 1, wherein 200 <N / V <800 kg applies to the power input of the stirrer N used per unit volume of the stirred reaction mixture V. m ^-1 . s ^-3 .