PRODUCTION DE SULFURES ET DE DISULFURES ORGANIQUES

PROCESS FOR THE PRODUCTION OF ORGANIC SULPHIDES AND DISULPHIDES

Abrégé anglais

Abstract of the Disclosure
Process for producing organic sulphides or disulphides wherein
a salt of the formula
<IMG>
is oxidised with a halogen or a pseudohalogen.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEPINED AS FOLLOWS:
1. A process for the preparation of an organic sulphide or disulphide
of formula I
<IMG> I
wherein x is 1 or 2 and R1 represents a radical corresponding to the formula
R2-O- or <IMG> , R2 being an aliphatic or alicyclic hydrocarbon radical
containing from 1 to 12 carbon atoms whose carbon chain may be interrupted by
one or more oxygen atoms and R3 and R4 being alkyl groups having 1 to 6 car-
bon atoms which process comprises oxidizing a compound of formula II
<IMG> II
wherein R1 is as defined above and Y is the cation of a monovalent metal,
with a halogen or pseudohalogen at a temperature of from -20 to 60°C in a
solvent which is a mixture of water and an aliphatic alcohol, the alcohol be-
ing from 50 to 80% by weight of the solvent, and then heating the reaction
mixture to cause the reaction mixture to separate into an alcoholic phase
which contains the required compound and an aqueous phase.
2. A process according to claim 1 wherein the oxidation is carried out
in the presence of an inert gas.
3. A process according to claim 2 wherein the oxidation is carried out
in the presence of air.
4. A process according to claim 1, 2 or 3 wherein the aliphatic alcohol
is isopropanol.
5. A process according to claim 1, 2 or 3 wherein Y is sodium.

6. A process according to claim 1, 2 or 3 wherein the halogen is
chlorine or bromine.
7. A process according to claim 1, 2 or 3 wherein the pseudohalogen
is cyanogen chloride or cyanogen bromide.
8. A process according to claim 1, 2 or 3 wherein R1 is a group
<IMG> wherein R3 and R4 are both ethyl or both methyl groups.
9. A process according to claim 1, 2 or 3 wherein R1 is a group
R2-O- in which R2 is a 1,3-dioxa-5-methyl-cyclohex-5-yl-methyl group.
10. A process according to claim 1, 2 or 3 wherein the reaction mixture
is heated to about 80°C to separate the mixture into two phases.

Description

~08;~7~0
This invention relates to a ~rocess for the production of organic
sulphides and disulphides corresponding to the formula (I)
Rl - C - S - C -
ll x
S S
wherein x is 1 or 2 and R represents a radical corresponding to the formula
R2_o- or R ~ , R being an aliphatic or alicyclic hydrocarbon radical
N--
R4/
containing from 1 to 12 carbon atoms whose carbon chain may be interrupted by
one or more oxygen atoms and R and R being alkyl groups having 1 to 6 car-
bon atoms which process comprises oxidizing a compound of formula (II)
Rl - c S9 ~3
.' S
wherein Rl is as defined above and Y is the cation of a monovalent metal,
with a halogen or pseudohalogen at a temperature of from -20 to 60 C in a
solvent which is a mixture of water and an aliphatic alcohol, the alcohol be-
ing from 50 to 80% by weight of the solvent, and then heating the reaction
mixture to cause the reaction mixture to separate into an alcoholic phase
whieh eontains the required eompound and an aqueous phase.
The oxidation may optionally be carried out in the presence of an
inert gas.
Preferred halogens are ehlorine and bromine; preferred pseudohalo-
gens are cyanogen chloride and cyanogen bromide.
The oxidation of eompounds corresponding to formula (II) into
compounds of formula (I) is basically known. Oxidation reactions of this
kind are accompanied by the formation of large quantities of inorganic salts
in aqueous solution.
-~ ~"
~ ~ -- 1 --
.

10~3~7~o
It i8 known from Cnnadian Patent Speci~lcation No.
856,834 thnt isopropyl xanthogenate can be oxidised with
sodium hypochlorite in a mixture o~ i~opropanol and water.
Although particularly pure x~nthogen disulphide is said to
be formed, large quantitles o~ water have to be used in
order to di~solve the sodium hypochlorite, 80 that large
quantitie~ Or dilute aqueouR mlneral salt solutions are
formcd.
The process according to the invention a~iord~ the
advantage over this prior art th~t only small quantities oi
water are required. A mixture Or water and aliphatic al~ohol
is u~ed ~or carrying out the proce~s. Monohydric or poly-
hydric aliphatic alcohols with 2 to 6 carbon atoms are
particularly suitable, monohydric alcohol~, especially
propanols and butanols~ bein~ particularly preferred.
.. ~
Particularly suitable radicals R2 in formula (I) are
alkyl radic~ls with 3 to 12 carbon atoms, cycloalkyl radicals
with 5 to 7 carbon atoms and straight-chain, branched-chain
and cycloalkyl ether radicals. Examples are isopropyl, n-butyl,
hexyl, octyl.
Particularly suitable radicals R3 are methyl, ethyl,
i-propyl and n-butyl.
l Cations of monovalent metals are in particular the cat-
- ions of sodium and potassium.
Particularly 3uitable starting materials are dlalkyl
dithiocarbamates having 1 to 4 carbon atom~ in the alkyl group
with sodium as the cation, also aliphatic ~odium xanthog~nates.
Examples o~ suitable starting materials are sodium diethyl
i dithio carbamate, 1,~-dioxa-5-ethyl-5-methylene xanthogenate,
sodium dimethyl dithio carbamate.
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-' ~ ' ~ ~ ' . ' . ' ... '

108~7~0
To carry out the proce~s, the tarting compounds are
dis~olved in water/alcohol mixtures, followed by the intro-
duction into the resulting solution with vigorous stirring Of
halogen or a p~eudohalogen optionally togather with
air. The temperatures applied are generally in the
range from about -20 to +60C and pre~erably in the range
from O to 30C.
The ratio by weight o~ water to alcohol in the mixture
generally amounts to between 5 : 95 and 95 : 5 and preferably
to between 20:80 and 50:50.
; Halogen or pseudohalogen may be used with advantage insubstantially stoichiometric quantities or even in a deficit
or exce~s. It is particularly preferred to use chlorine gus
and cyanogen chloride. Inert gas, for example air or nitrogen,
may be added to the halogen in a ratio by volume of halogen
to inert gas Or I :lOO.
On completion of the reaction (reilected in many cases
in a rall in the pH-value), the reaction mixture may be
heated to temperatur~ of up to 80~C. As a result the
reaction mixture generally separates into two liquid phase~,
which the alcoholic phase contains the organic sulphide
or disulphide iormed and the aqueous phase contains the
mineral salt iormed. The pha~es may readily be separated
one rrOm the other.
The quantity Or water in the reaction mi~ture may be
selected in such a way that all the mineral salt dissolves,
in which ca~e a highly concentrated salt solution~ which
may readily be worked up, is obtained. It is also poesible
to use a ~maller quantity oi water, in which case some oi
the salt is obtained in solid rorm. The alcohol may also
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10~7~)
be used in a quantity sufficient to dissolve the organic
sulphide or d~eulphide, in which case a solution 18 obtained
which may readily be worked up by distillation after the
material has crystallised out. ~lternatively, the alcohol
may bc u~ed in a smaller quantity, in which case a suspension
of the organic sulphide or disulphide in a concentrated
alcoholic solution o~ this substAnce i9 obtained. In all
cases, the reaction mixture can be worked up without
difficulty. Eifluents containing inorganic snlts are
prevented from being formed in large quantities by volume.
.,
,. :
. 1 ' .
,
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: ~,
.
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101~'~73(~
EX~MPLE 1
Production of tetraethyl thiuram disulphide
A suspension Or ~odium diethyl dithiocarba~nte wa~
prepared by kno~nn methods from 275 g o~ water~ 40 g oi
NaOH, 76 g of carbon disulphide and 73 g oi diethylamine.
Following the addition of 308 g of isopropanol, the suspension
chnnges lnto a homogeneou~ solution. A mixture of chlorine
and air in a ratio o~ approximately 1:50 was then introduced
with vigorous stirring at room temperature through a gassing
stirrer or through a gassing pipe~ After a while the reaction
products, sodium cAloride and tetraethyl thluram di3ulphide,
began to precipita~e. A~ter the pII-value oi the reaction
mixture had fallen from its original level o~ approximately
14.0 to approximately pH 7.0, the introduction of chlorine
was stopped and the reaction mixture was heated to
approximately 80C. As a result all the solid reaction
products were dis~olved, followed by phase separation into
an aqueous phase (311.1 g) and an organic phase (458.1 g).
The aqueous phase wa~ concentrated by evaporation in a
rotary evaporator, leaving a solid residue o~ 67.3 g (mostly
NaCl).
The organic phase was cooled to 0C and the tetraethyl
thiuram disulphide precipltated ln the iorm of ilne crystals
wa8 eeparated Ori. Yleld 121.3 g (82~ Or the theoretical
yield)~ mp 71C. The mother llquor was concentrated by
evaporation~ leaving a resldue oi 14.2 g.
EXAMPLE 2
Tetraethyl thiuram disulphide
The procedure was a~ described in E~ample 1, except
that the quantity Or water used was reduced irom 275 g to 215 g
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730
and the quantity Or isopropanol from 308 g to 300 g. The
cffect of thie was that not all the dithiocarbamate was
dissolved at the beginnlng of oxidation. ~owever, this
(loes not have any adverse effect upon the oxidation proce~s.
~queous phase: 252 g, of which 64.9 g are made up by salt-like
residue. Organic phaee: 435.2 g. Yield: 124.4 g (85% of the
theoretical yield), mp 71C. Residue following evaporation of
the mother liquor: 12.5 g.
~XA~IPL~ 3
nis-(1,3-dioxa-5-ethyl-5-hydroxy methyl cyclohexane xanthogen~-
disulphide.
The xanthogenate was produced in known manner from 146 g
of 1,3-dioxa-5-ethyl-5-hydroxymethyl-cyclohexane
~': ~ O--C~I2
H2C~ C--CH2--
O-CH2 C2H5
; 40 g of sodium hydroxide, 76 g of CS2 and 52 g of water.
Isopropanol (425 g) and water (75 g) were then added
to the viscou8 aqueous xanthogenate solution, the mixture
was cooled to approximately 0C and a mixture of chlorine
gas and air in a ratlo Or 1: 50 was introduced with vigorous
- stirring through a gaseing pipe or through a gassing stirrer.
After the chlorine gas/air mixture had been introduced ior
about 4 to 6 hours, the end Or the reaction was rerlected
in a sudden f811 of the p~ to below 7. The react~on mixture
was then heated to 50C, as a result of which all the
xanthogen disulphlde and part of the salt were diesolved.
After the ealt (approximately 35 g) had been filtered Ori~
the aqueou~ phase (74.8 g) was eeparated o~f. The product
was recryetallised from the organic phaee (679.3 g) at 0C.
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108~73(~
,
Yield: 164.7 ~ (75~ of the theoretical yield),
~MPLE 4
Bis-(1,3-~ioxa-5-ethyl-5-hydroxymethyl cyclohexane xanthogen)-
disulphide
The procedure w~s a~ described in Example 3, e~cept that
the xantho~enate solution wa~ diluted with 350 g a~ oppo~ed to
425 g oi isopropanol and with 150 ~ instead of 75 g of water.
Aqueous ~hase: 228.5 g, 57.8 g of salt contained therein.
Or~anic phase: 555.1 g, contained therein: yield 178.7 g
(81% of the theoretical yield).
EXAMPLE 5
Bis-dimethyl thiocarbamoyl sulphide (tetramethyl thiuram
monosulphide)
68 g of cyanogen chloride were added dropwise with
vigorous stirring at 25C to 715 g of aqueous sodium dimethyl
dithiocarbamatc solution (42~) and 250 g of n-butanol. On
`:
completion of the reaction, the pH-value was 8.0 The suspension
formed was then heated to 80C, as a result of which the sulphide
di~solved and phase separation occurred. The aqueous
phase was separated ofi and the product crystallised
out from the organic phase at room temperature. Yield:
207.2 g (95% of the theoretical yield).
EXAMPLE 6
Bis-dimethyl thiocarbamoyl Yulphide (tetramethyl
, .. . .
~- 25 thiuram monosulphide)
300 g oi n-butanol were added to 357 g of an aqueous
sodium dimethyl dithiocarbamate solution (40%). A mlxture
of chlorine and air (1:50) was introduced with vigorous
~, stirring at room temperature through a ga8sing stirrer.
The end of o~idation wa~ reilected in the sudden iall oi
-:~
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.~
, .-.. ..

~08;~7~3()
the pH-value to below 7Ø Following pH ad~ustment to
8.0 with 50% sodium hydroxlde, 24.5 g Or sodium cyanide
were added and the suspension wa~ hea~ed to 80C, resulting
in the formatlon of a homogeneous organlc phase containing
the sulphide, and an aqueous suspension becQuse not all the
salt was di~solved. The organic phase was separated ofr and
the product crystallised out at room temperature. Yield:
81.2 g (78% of the theoretical yield).
'
.
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