Sulfoxide (R2SO) is any of various organic sulfur compounds having the group -SO
(sulfinyl group) whereas sulfone (RSOOR) with the group -SO2 (sulfonyl group).
They are derived from oxidation of sulfides ((R-S-R). Thioethers (organic sulfides) can be oxidized either to oxidation state -1
disulfides (R-S-S-R) or to oxidation state 0 sulfoxides (R-S(=O)-R)
which can be
further oxidized to the corresponding oxidation state +2 sulfones (R-S(=O)2-R)
depending on the structure of the thioether. They are widely used as solvent of
both extraction and reaction as well as intermediates for the synthesis of
textile chemicals and pharmaceuticals and agrochemicals.
Thioether is the sulfur analog of the
ether (R-O-R), which sulfur atom replaces the oxygen.
Sulfur and oxygen belong to the same group in the periodic table
share similar chemical properties. The functional groups
of sulfur and oxygen share similar chemical bonds
and properties. Ethers can only be oxidized to peroxides (R-O-O-R).
But thioethers (R-S-R) can be oxidized either to disulfides (R-S-S-R) or to sulfoxides (R-S(=O)-R)
which can be
further oxidized to the corresponding sulfones (R-S(=O)2-R)
depending on the structure of the thioether.
Dimethyl
Sulfide is the simplest thioether.
The compound is a clear,
flammable liquid; insoluble in water;
boiling point 37C; with a distinctive garlic-like odor. It is used as a flavor component
to
enhance corn-related flavors. It
is used
as a presulfiding agent in the refinery and petrochemical
production.
The catalysts in hydrocracking, hydrodenitrification, hydrodesulfurization
and reforming processes are used in oxide forms, which
must be converted to the active sulfide form during
the start-up to prevent the reduction of the catalysts
to their base material by heat. The sulfur sources include
alkyl mercaptans (methyl mercaptan, ethyl mercaptan,
butyl mercaptan), dimethyl sulfide, dimethyl sulfoxide,
dimethyl disulfide, and tert-nolyl polysulfide. They
are used to modify the reactivity of catalysts to use
in high temperature process furnaces. Dimethyl Sulfide is used to prevent the
coke deposits which acts as a thermal insulator in the tube as it accumulates
in pyrolysis furnaces. It is also used in steel mill furnaces to
control dusting. Dimethyl Sulfide is included as a component of dangerous gases to detect
the leaks by smell.
Thioethers have
applications in organic synthesis as
solvents as well as reagents. Acyclic thioethers with oxidized branches
such as alcohol, aldehyde, ester, acid, beta-ketone, phenol
demonstrate centres of greater polarity and additional functional
sites for the
additional uses. Cyclic sulfides containing oxidized carbon
atoms would
involve extensive S-oxidation.
Thioethers are
involved in versatile
in the synthesis of
specific compound classes include agricultural chemical, property-enhancing additives,
pharmacological drugs, chemical resistant polymers,
detergents, and rubber antioxidants. Some examples of aliphatic and aromatic thioethers found
in flavouring agents include:
Thioethers
|
CAS
RN
|
Methyl sulfide |
75-18-3 |
Methyl phenyl sulfide
|
100-68-5
|
Diethyl sulfide
|
352-93-2
|
Butyl sulfide
|
544-40-1
|
Allyl sulfide
|
592-88-1
|
Methyl ethyl sulfide
|
624-89-5
|
Benzyl methyl sulfide
|
766-92-7
|
Bis(methylthio)methane
|
1618-26-4
|
(1-Butenyl-1) methyl sulfide
|
32951-19-2
|
Thioethers
with oxidized branches |
CAS
RN
|
o-(Methylthio)phenol
|
1073-29-
|
Ethyl 3-methylthiopropionate
|
133327-56-5
|
Methyl 3-methylthiopropionate
|
13532-18-8
|
1-(Methylthio)-2-butanone
|
13678-58-5
|
1-Methylthio-2-propanone
|
14109-72-9
|
3-(Methylthio)butanal
|
16630-52-7
|
3-(Methylthio)propyl acetate
|
16630-55-0
|
4-(Methylthio)butanol
|
20582-85-8
|
Ethyl 4-(methylthio)butyrate
|
22014-48-8
|
2-Methylthioacetaldehyde
|
23328-62-3
|
4-(Methylthio)-4-methyl-2-pentanone
|
23550-40-5
|
3-(Methylthio)
|
3268-49-3
|
4-(Methylthio)-2-butanone
|
34047-39-7
|
3-Methylthiohexanal
|
38433-74-8
|
Di(butan-3-one-1-yl) sulfide
|
40790-04-3
|
2-(Methylthio)
|
40878-72-6
|
4-(Methylthio)butanal
|
42919-64-2
|
Ethyl 2-(methylthio)acetate
|
4455-13-4
|
3-(Methylthio)propanol
|
505-10-2
|
3-(Methylthio)-1-hexanol
|
51755-66-9
|
3-(Methylthio)hexyl acetate
|
51755-85-2
|
4-(Methylthio)-2-oxobutanoic acid sodium salt
|
51828-97-8
|
Methyl 4-(methylthio)butyrate
|
53053-51-3
|
2,8-Dithianon-4-ene-4-carboxaldehyde
|
59902-01-1
|
2-(Methylthiomethyl)-3-phenyl-propenal
|
65887-08-3
|
Methylthiomethyl hexanoate
|
74758-91-1
|
Methylthiomethyl butyrate
|
74758-93-3
|
Cyclic Thioethers
|
CAS
RN
|
1,4-Dithiane
|
505-29-3
|
Trithioacetone
|
828-26-2
|
4,5-Dihydro-3-(2H)-thiophenone
|
1003-04-9
|
2-Methyl-1,3-dithiolane
|
5616-51-3
|
2-Methyltetrahydrothiophen-3-one
|
13679-85-1
|
2,5-Dihydroxy-1,4-dithiane
|
40018-26-6
|
2,5-Dimethyl-2,5-dihydroxy-1,4-dithiane
|
55704-78-4
|
2-Methyl-4-propyl-1,3-oxathiane
|
67715-80-4
|
|