DE2743513C2 - Process for producing a thiocarbamic acid ester - Google Patents

Description

R ¹ and R ² independently of one another are hydrogen or alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, cycloalkenyl, alkoxy, alkenoxy, alkoxyalkyl, alkylthioalkyl, alkoxyalkenyl, alkylthioalkenyl or heterocyclic groups mean, with halogen, cyano, nitro, trifluoromethyl, alkoxy and / or
Alkyl having 1 to 4 carbon atoms may be substituted; or

R ¹ and R ² together with the nitrogen atom to which they are attached form a nitrogen-containing heterocyclic ring

in anhydrous medium at a temperature of at least about 10 ° C and a pressure of at least about 0.98 bar (Oatü);

b) Reaction of the product from step a) with an organic halide of the general formula 11

R ³ X (II)

wherein R ^{3 is} an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, cycloalkenyl, alkoxy, alkenoxy, alkoxyalkyl, alkylthioalkyl, alkoxyalkenyl, alkylthioalkenyl or heterocyclic group with halogen Cyan, nitro, trifluoromethyl,

Substituted alkoxy with 1 to 4 carbon atoms and / or alkyl with 1 to 4 carbon atoms can be; and

X means chlorine, bromine or iodine,

in an anhydrous medium at elevated temperature and a pressure of at least about 0.98 bar (0 atü) to a thiocarbamic acid ester and a salt of the general formula III

R ¹

__R ² - ^NH A ^X : ...- .._... ^m

containing mixture; and

c) separation of the thiocarbamic acid ester from the mixture according to step b), characterized in that that steps a) and b) are carried out simultaneously at a temperature of up to 160 ° C., a pressure from 0.98 bar to 35.4 bar (0 to 35.2 atmospheres) and with a molar ratio of COS: amine of 0.502 up to 0.75 moles works.

2. The method according to claim 1, characterized in that the thiocarbamic acid ester in of stage b) is obtained, and the organic halide 11 is used as a solvent.

3. The method according to claim ί, characterized in that at a temperature up to ΠO ⁰ C, a pressure of 1.7 bar to 11.3 bar (0.70 to 10.5 atü) and a molar ratio of COS: amine of 0.515 to 0.55 works.

4. The method according to claim 1, characterized in that the organic halide in one Ratio of 1.0 to 1.5, based on the reaction product of COS with the amine of the formula I, begins.

5. The method according to claim 1, characterized in that the molar ratio of the organic halide to the thiocarbamic acid ester is 1.03 to 1.1.

The invention relates to a method for producing a thiocarbamic acid ester.

The thiocarbamic acid esters can be used for a wide variety of purposes. Individuals are like that b5 active herbicides, are effective in inhibiting the growth of microorganisms such as bacteria, and others still others are active insecticides. The following procedures are for the preparation of these compounds known:

According to US-PS 29 83 747 zinc chloride is used as a catalyst for the direct implementation of Carbamylchlori-

used with mercaptans to form various thiocarbamic acid esters Although the reaction without Solvent can be carried out, if a solvent is used, one for the catalyst inert can be used.

In US-PS 29 13 327 is a process for the preparation of the sodium salt of a mercaptan and the following Reaction with a carbamyl chloride in the presence of a solvent described. The usage the sodium salt of mercaptan causes problems in the filtration and handling of the solid. The use of the solvent reduces the capacity of the reaction vessel and can cause recovery problems cause. Furthermore, it is difficult to use the hydrogen which is used in the production of the Sodium salt is formed, to be eliminated.

In US-PS 38 36 524 the reaction of a carbamyl chloride with a mercaptan in the presence of a aqueous solution of an alkaline agent described. This reaction requires considerable agitation in order to to form a large interface between the two liquid phases, as well as a high concentration of alkaline agents in order to achieve the desired degree of conversion and product purity.

In US-PS 31 33 947 the implementation of a secondary or primary amine with carbonyl sulfide in Presence of a basic material such as an amine including a tertiary amine and then reaction of the intermediate product with an organic sulfate, such as dialkyl sulfate or diallyl sulfate, described. The cost of this process is “increased by the loss of alkyl sulfate.

Carbonyl sulfide is reacted with a primary or secondary amine in an aqueous alkaline solution at a temperature of 20 ^° C. or below according to US Pat. No. 3,167,571. The condensation of the amine salt of thiocarbamic acid is then effected by reacting the salt with an organic halide. This process has two disadvantages. First, low activity organic halides do not react at this temperature. Although such few active halides at temperatures of about 100 ° C around easily react, such temperatures can not be applied because the aqueous medium at temperatures much above 20 ⁰ C, the COS does not absorb Second, the amount must of COS be accurately controlled in this method, as excessive amounts cause the thiocarbamate to decompose. This means that there are significant amounts of by-products that can only be controlled through the loss of yield.

Also according to US-PS 31 51 119 low temperatures are used, what those listed above Causes disadvantages.

The most recent method involving the use of COS is found in US Pat. No. 3,954,729, according to US Pat which a secondary amine in the presence of an aromatic solvent with carbonyl sulfide to one Amine salt of thiocarbamic acid is reacted, which is then reacted with an alkyl halide to give the thiocarbamic acid ester is implemented. With stoichiometric molar ratios of the carbonyl sulfide to the amine, however a maximum of 92% purity can be obtained without aging the product. Aging and an excess of Carbonyl sulfide reduced the purity even further. For this reason, to get the purest possible product obtained, the use of a 4mol-% deficiency of carbonyl sulfide in the is in this patent first reaction and as precise a stoichiometric amount as possible of the alkyl halide in the second reaction deemed necessary. To achieve both a maximum yield per batch and minimal quantities of Obtaining byproducts requires a high level of accuracy in measuring out individual reagents necessary. However, this is because of the cost of additional monitoring and lack of flexibility undesirable. The formation of by-products is additionally reduced by limiting the reaction temperature in the second reaction to between 0 ° and 60 ° C further reduced. Although the alkyl halides that are in the Examples of this US patent are given, have a reasonable reaction rate in this temperature range, this does not apply to less active alkyl halides. For example, they react low alkyl chlorides extremely slowly or not at all within this temperature range.

In view of these problems, it is an object of this invention to provide a process for the preparation of thiocarbamic acid esters with high yield and conversion, as well as savings in raw materials and Operating costs, to find.

Another object of this invention is to provide a process for the preparation of thiocarbamic acid esters find which no precise monitoring, as is required according to US-PS 39 54 729, needs and which the use of those alkyl chlorides which are unreactive in the latter known process, permitted

The invention relates to a new process for the preparation of compounds under the name Thiocarbamates or thiocarbamic acid esters are known. The synonym thiol carbamate is used in the literature also used to denote this class of compounds. In the following, these compounds are denoted Thiocarbamic acid ester used

It has been found that the use of the new process thiocarbamic acid esters in high Yield and purity can be produced efficiently and economically. The invention therefore relates to a Process for the preparation of a thiocarbamic acid ester by reacting

a) COS with an amine of the general formula I.

R ¹
R ² -NH (D.

R ¹ and R ² independently of one another are hydrogen or alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl,

Cycloalkenyl, alkoxy, alkenoxy, alkoxyalkyl, alkylthioalkyl, alkoxyalkenyl, alkylthioalkenyl or mean heterocyclic groups which, with halogen, are cyano, nitro, trifluoromethyl, alkoxy and or

Alkyl having 1 to 4 carbon atoms may be substituted; or

5 R ¹ and R ² together with the nitrogen atom to which they are attached form a nitrogen-containing heterocyclic ring

in anhydrous medium at a temperature of at least about 10 ° C and a pressure of at least about 0.98 bar (Oatü);

b) Reaction of the product from step a) with an organic halide of the general formula II

R ³ X (II)

15 wherein R ^{3 is} an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, cycloalkenyl, alkoxy, alkenoxy.

Alkoxyalkyl, alkylthioalkyl, alkoxyalkenyK alkylthioalkenyl or heterocyclic groups

means that with halogen cyan, nitro, trifluoromethyl,

Substituted alkoxy with 1 to 4 carbon atoms and / or alkyl with 1 to 4 carbon atoms

can be; and
20 X means chlorine, bromine or iodine,

in an anhydrous medium at elevated temperature and a pressure of at least about 0 atü to one a thiocarbamic acid ester and a salt of the general formula III

+ γ- (ΠΙ)

25 R ¹

R ² -NH ₂ ⁺ X
containing mixture; and

c) Separation of the thiocarbamic acid ester from the mixture according to step b), which is characterized ·? · Is that steps a) and b) are carried out simultaneously at a temperature of up to 160 ° C, a pressure of 0.98 bar to

Γ; 35.4 bar (0 to 35.2 atmospheres) and with a molar ratio of COS: amine of 0.502 to 0.75 mol

Γ works.

,.: The individual terms used here are defined below

;: Under alkyl is a monovalent straight or branched saturated aüphatic hydrocarbon group

understood with 1 to 12, preferably 2 to 6 and especially 2 to 4, carbon atoms, for example

Methyl, ethyl, propyl, i-propyl, t-butyl or 2-methyloctyl.
Alkenyl stands for a monovalent straight or branched aliphatic hydrocarbon group with 2 to 8, preferably 2 to 6 and in particular 2 to 4, carbon alloys which has at least one double bond, for example allyl, butenyl or butadienyl.

,:, Alkynyl is a monovalent straight or branched aliphatic hydrocarbon group with few

; J at least a triple bond and understood with 3 to 6 carbon atoms, for example propargyl or

tjj 45 isobutynyl.

γ aryl stands for a monocyclic or bicydic aromatic hydrocarbon group, both

$, for example phenyl or naphthyl.

■ Aralkyl stands for an alkyl group, as defined above, in which a hydrogen atom is replaced by one above

/ - Defined aryl group is replaced, for example benzyl, Pheiiäthyl or naphthylmethyl.

:. 50 Cycloalkyl stands for a monovalent cyclic saturated hydrocarbon group with 3 to 7 carbon atoms Men, for example cyclobutyl or cyclohexyl.

ν Cycloalkenyl is a monovalent cyclic hydrocarbon group with 5 to 7 carbon atoms

ι; ' and understood at least one double bond, for example cyclohexenyl.

{: ■■ .. Under alkoxy is a monovalent straight or branched aliphatic hydrocarbon group with 1 to 8,

"j · 35 preferably 2 to 6 and in particular 2 to 4, carbon atoms understood, for example ethoxy or |; t-butoxy.

p. Alkenoxy represents a monovalent straight or branched hydrocarbonoxy group with 2 to 8, preferably

fl 2 to 6 and especially 2 to 4 carbon atoms and with at least one double bond, for example

|, i butenoxy or pentenoxy.

fs. Among 60 alkoxyalkyl is an alkyl group is understood as defined above in which a hydrogen atom by 'p a phenoxy or alkoxy group, as defined above, substituted, for example, phenoxyethyl, methoxyethyl

(i or ethoxyethyl.

[ Alkylthioalkyl stands for an alkyl group as defined above in which a hydrogen atom is replaced by a monovalent

I _1, ge straight or branched aliphatic hydrocarbon group having Thiokohlenwasse ^r 1 to 8 carbon atoms, or

65 phenylthio group is substituted, for example methylthioethyl or phenylthioethyl.

Alkoxyalkenyl is understood to mean an alkenyl group as defined above in which a hydrogen atom ^: is substituted by an alkoxy group as defined above, for example ethoxybutenyl.

Alkylthioalkenyl stands for an alkenyl group defined above in which a hydrogen atom is replaced by a monovalent

ge straight or branched saturated aliphatic thiocarbon group having 1 to 8 carbon atoms is substituted, for example ethylthiobutenyl.

Halogen stands for chlorine, fluorine and bromine.

Heterocyclic ring group means a monovalent group that has carbon atoms and other atoms in a monocyclic, bicyclic, or tricyclic ring that contains 3 to 8 atoms per ring. The ring can be saturated or have one or more double bonds. Other atoms are nitrogen, phosphorus and sulfur. If there are two or more other atoms in a group, they can be the same or different atoms. Examples of nitrogen-containing heterocyclic rings in which R ¹ and R ² together with the nitrogen atom to which they are attached form a group are, for example, pyrryl, pyrroallydyl, pyrazolyl, aziridinyl, oxazolydyl, thiazolydyl and polyalkyleneimine with 2 to 6 Carbon atoms. Examples of heterocyclic rings, which can each ^{stand for R 1} , R ² or R ³ , are furyl, thiofuryl, pyranyl, benzofuryl, tetrahydrofuryl and the above. Heterocyclic rings, which can each ^{stand for R 1} , R ² or R ³ , are also understood to mean methyl groups in which one hydrogen atom has been replaced by a monocyclic, bicyclic or tricyclic ring of the type mentioned above. Examples of such groups are furfuryl and tetrahydrofurfuryl.

The ranges given above for the number of carbon atoms are inclusive of lowest and highest number mentioned.

According to the invention, one mole of carbonyl sulfide is combined with about two moles of a primary or secondary amine, preferably a secondary amine, reacted and the product subsequently with an organic halide implemented into the desired product.

The reaction of COS with the amine must be carried out under anhydrous conditions in order to achieve a Implementation of COS with water to prevent the formation of hydrogen sulfide and others Would result in contamination. In order to achieve the fullest possible conversion of the amine, a Excess of COS to the extent that the COS: amine molar ratio is about 0.502 to about 0.75, and in particular from about 0.515 to about 0.55 is used. Although the pressure and temperature at which the Reaction is carried out, are not essential, is generally carried out at a temperature of about 10 ° C to about 160 ° C, preferably from about 20 ° C to about 110 ° C, and at a pressure of about 0.98 to 35.4 bar (0 to 35 atm), preferably from 1.7 bar to 11.3 bar (0.7 to 10.5 atm) worked.

The reaction of COS with amine can be carried out in the absence or in the presence of an anhydrous aprotic Solvent are run. The term aprotic solvent means an organic solvent, that doesn't give up or take in protons, understood. Examples of such solvents are benzene, Toluene, alkanes and their halides. Solvent, which over a wide temperature range the reaction product hydrolyze, are unsuitable, such as water, alcohols, aldehydes or ketones. Preferably, the reaction is either without a solvent or with the organic halide or the thiocarbamic acid ester product carried out as a solvent. In particular, either will not be a solvent or the thiocarbamic acid ester is used.

The second step of the reaction, the amine salt, which was formed in the COS-amine reaction, is reacted with the organic halide is carried out under anhydrous conditions This is particularly important because at temperatures above 6O ⁰ C, the amine salt is decomposed and gaseous COS is formed which reacts to H2S and CO2 in the presence of water. The H2S reacts with the unreacted salt and the reaction product, ie the ester, to form by-products and thereby reduces the purity of the desired reaction product. Another advantage of the anhydrous reaction conditions is that a larger number of organic halides can be used, including less reactive organic halides which only react well at temperatures above about 60.degree. Examples of the latter are lower alkyl chlorides having 1 to 4 carbon atoms. If an aqueous medium is used, large amounts of by-products would arise at the temperatures mentioned, since the rate at which carbonyl sulfide is released increases with higher temperature. In an anhydrous medium, the temperature has essentially no influence on the formation of by-products, since in the absence of water carbonyl sulfide does not form hydrogen sulfide, which can react with the salt of the ester

Therefore, the amine salt / organic halide reaction will take place at a temperature of at least about 60.degree. C., preferably from about 60.degree. C. to about 160.degree. C. and in particular from about 70.degree. C. to about 110.degree. The reaction is carried out at a pressure of at least 0.98 bar, preferably from 0.98 to 35.4 bar (0 to. about 35 atmospheres), in particular from 1.7 bar to 113 bar (0.7 to 10.5 atmospheres). This implementation can also without a solvent or in the presence of an anhydrous aprotic solvent, as described above for the COS / amine reaction. Preferably either no solvent or the; organic halide or the thiocarbamic acid ester product used. In particular, either is seed Solvent or the thiocarbamic acid ester product used

In order to obtain a more complete conversion of the amine salt to the thiocarbamic acid ester, an excess of organic halide can be used, for example the molar ratio of halide: salt, of about 1.0bisetwal, 5, preferably vonetwal, 03bisetwal, l.

According to the invention, preference is given to preparing compounds in which the substituents are as follows Have meanings:

a) R ¹ and R ² together with the nitrogen atom to which they are bonded form a polyalkyleneimine with 2 to

6 carbon atoms and R ³ means alkyl with 1 to 12 carbon atoms:

b) R ¹ , R ² and R ³ independently of one another denote alkyl having 1 to 12 carbon atoms;

c) R ¹ and R ² independently of one another denote alkyl having 1 to 12 carbon atoms and R ³ denotes benzyl;

d) R ¹ and R ² independently of one another denote alkyl having 1 to 12 carbon atoms and R ³ denotes

Haloalkenyl of 2 to 8 carbon atoms;

e) R ¹ and R ² independently of one another denote alkyl with 1 to 12 carbon atoms and R ³ denotes a benzyl group substituted by chlorine, alkoxy with 1 to 4 carbon atoms, nitro and / or trifluoromethyl;

f) R ¹ and R ^{2 are} n-propyl, R ³ is ethyl and X is chlorine;

g) R ¹ and R ^{2 are} isobutyl, R ³ is ethyl and X is chlorine;

h) R ¹ and R ² together with the nitrogen atom to which they are attached form hexamethyleneimine, R ³

means ethyl and X means chlorine;
i) R ¹ , R ² and R ^{3 are} n-propyl and X is chlorine;
j) R ¹ means ethyl, R ² means η-butyl, R ³ n-propyl and X means chlorine;
k) R ¹ means ethyl, R ² means cyclohexyl, R ³ means ethyl and X means chlorine;
1) R ¹ and R ² mean ethyl, R ³ means p-chlorobenzyl and X means chlorine.

Examples

In experiments 1 to 7 below, the amine was placed in a pressure vessel and the organic Halide added to the amine. The jar was then closed and carbonyl sulfide was passed under it clogged the surface of the liquid. The contents were stirred with a magnetic stirrer and placed in a heated Bath placed. The reaction was complete in 1 hour or less. The amine hydrochloride was in Dissolved water and removed from the product. The product obtained was diluted with water and aqueous Washed hydrochloric acid. The aqueous portions were then extracted with hexane and the product under Freed from solvent in vacuo

In Run 8, the amine was first saturated with carbonyl sulfide at atmospheric pressure. The saturation was then maintained while the organic halide was added.

Table I below shows the reactants used in the experiments and those resulting therefrom obtained thiocarbamic acid ester listed. Table II shows the ratio of the reactants and the Reaction conditions for each experiment with the results obtained stating the yield and the Purity.

Table I Reactions

Reaction amine

Organic halide

product

A di-n-propylamine

B diisobutylamine

C hexamethyleneimine

D di-n-propylamine

E ethylcyclohexylamine

F ethyl-n-butylamine

G diethylamine

Table II

Reaction conditions and results

Ethyl chloride ethyl chloride ethyl chloride

n-propyl chloride ethyl chloride n-propyl chloride p-chlorobenzyl chloride

S-ethyl dipropyl thiocarbamate S-ethyl diisobutyl thiocarbamate S-ethylhexahydro-1 H-azepine-1 -carbothio-

S-propyl dipropyl thiocarbamate S-ethyl cyclohexyl ethyl thiocarbamate S-propylbutylethylthiocarbamate S-p-chlorobenzyl diethylthiocarbamate

Attempt no.

Reaction solvent

COS: amine molar ratio

Halide: amine molar ratio

Temperature "C

Maximum
pressure
kg / cm ² *)

yield

Degree of purity

1 A. no 0.585 0.585 77 96.0 99.6 2 B. no 0.533 90 100.0 96.4 3 C. no 0.508 0.626 90 96.3 95.5 4th D. no 0.649 0.550 90 100.0 99.5 5 E. no 0.533 0.604 91 100.0 99.4 6th F. no 0.583 0.550 91 94.8 99.5 7th A. product 0349 0.637 101 100.0 99.1 8th G no (a) 0.500 70-90 98.3 96.0 (b) (a) Saturation of the system with COS, which is maintained throughout the reaction (b) Purity of the starting halide 93.1% Upper pressure

Activity of connections

As stated above, the thiocarbamic acid esters made by the process of the present invention are useful as pre- and post-emergence herbicides, growth retardants and insecticides. the herbicidal action of some of the compounds according to the above examples according to the invention Procedures established was determined by the screening tests below

Pre-emergence herbicider screening test

Using an analytical balance, 20 mg of the compound to be examined is weighed out on a piece of glassine weighing paper. The paper and the compound are placed in a 30 ml wide neck bottle and 3 ml of acetone containing 1% "Tween 20" (an emulsifier, namely polyoxyethylene sorbitan monolaurate) are added to dissolve the compound. If the material is not soluble in acetone, another solvent, such as water, alcohol, or dimethylformamide, is used in its place. In the case of dimethylformamide, only 0.5 ml or less is required to dissolve the compound. Another solvent is then added to bring the volume to 3 ml. The 3 ml solution is sprayed evenly on the soil, which is in a small plastic bowl, one day after weed seeds have been planted. A No. 152 DeVilbiss atomizer is used to apply the spray with compressed air at an overpressure of 0.352 kg / cm ² . The amount applied is 8.97 kg / ha and the spray volume is 1337.5 liters per ha.

The day before the treatment, the plastic bowl, which is approximately 17.5 cm long, 12.5 cm wide and 7 cm deep, is Filled with loamy sandy soil to a depth of 5 cm. Seeds from seven different species of weed are planted in individual rows, one species per row across the width of the bowl. The seeds are made with soil covered so that they lie at a depth of about 1.3 cm. The seeds used are: fingergrass (Digitaria sanguinalis), blue-green millet (Setaria glauca), common amaranth (Amaranthus retroflexus), Indian Mustard (Brassica juncea), curly dock (Rumex crispus), chicken grass (Echinochloa crusgalii) and panicle oats (Avena sativa). The seeds are planted so abundantly that about 20 to 50 seedlings, depending on their size are present in each row after emergence.

After the treatment, the pods are placed in a greenhouse at a temperature of around 20 to 30 ^c C and watered by spraying. Two weeks after the treatment, the degree of damage or the control is determined by comparison with untreated plants of the same age. The degree of control, which ranges from 0 to 100%, is recorded as a percentage destruction for each weed species, with 0 representing no destruction and 100% representing complete destruction.

Post-emergence herbicider screening test

Seeds of six types of plants, namely fingergrass, chicken grass, panicle oat, Indian mustard, curly dock and spotted beans (Phaseolus vulgaris) are planted in the plastic trays before emergence, as in the experiment. The trays are placed in a greenhouse at 20-30 ° C and watered daily by spraying. Approximately 10-14 days after planting, when the cotyledons of the bean plants are almost fully developed and the first triple leaves begin to form, the plants are sprayed. The spray is prepared by weighing 20 mg of the compound to be tested, dissolving it in 5 ml of acetone, the! % "Tween 20" and adding 5 ml of water. The solution is sprayed onto the foliage using a No. 152 De Vilbiss atomizer with an excess pressure of 0.352 kg / cm ² . The spray concentration is 0.2% and the amount applied is 8.97 kg / ha, the spray volume is 4452 liters / ha. The level of weed control is recorded 14 days after treatment. The system is the same as previously described for the pre-emergence test. The results of these tests are shown in Table III

Table IH
Herbicidal effect

Before emergence product: percentage destruction at 8.97 kg / ha

Experiment No. FG BB HG RH GA IS KA

2 0 95 80 100 0 0 0 3 20th 90 95 100 0 10 40 4th 90 80 97 100 30th 20th 0 5 98 98 90 100 10 10 10 6th 20th 80 70 100 10 in 10

Product of
Attempt no.

After emergence: percentage destruction at 8.97 kg / ha FG HG RH IS

KA

SB

Symbols:

0 0 0 30 0

0 0

80 0 0

FG: fingergrass BB: blue-green millet HG: chicken grass

0 0 80 0 0

RH: panicle GA: common amaranth IS: Indian mustard

0 0 0 98 0

0 10 0 0 0

KA: Krauser Ampfer SB: Piebald beans

Claims (1)

Patent claims: 1. Process for the preparation of a thiocarbamic acid ester by reacting
a) COS with an amine of the general formula I. R ¹ R ² - NH (I) ίο "■ ■" - · ■ - ■ - - wherein