Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfur halides
Reexamination Certificate
2000-06-23
2002-08-27
Vollano, Jean F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfur halides
C562S828000
Reexamination Certificate
active
06441229
ABSTRACT:
The present invention relates to a method for preparing alkane sulfonyl halides. More particularly, this invention concerns a method for producing higher-alkane sulfonyl chlorides through the oxidation of alkyl mercaptans or dialkyl disulfides while inhibiting the formation of undesirable byproducts.
BACKGROUND OF THE INVENTION
Alkane sulfonyl halides, particularly alkane sulfonyl chlorides, are know for their utility in imparting functionality into various compounds or as intermediates to modify various compounds, including pharmaceuticals, agriculture chemicals, photographic chemicals and the like, in order to increase their efficacy, to protect sensitive functional groups during certain processing steps, or to improve the recovery and purity during isolation procedures.
A number of prior-art methods are known for preparing alkane sulfonyl halides, particularly methane sulfonyl chloride. A known preparation process for methane sulfonyl chloride involves the reaction of chlorine with methyl mercaptan or dimethyl disulfide in an aqueous solution of hydrogen chloride. The products of such reaction generally include methane sulfonyl chloride, hydrogen chloride, and at least one undesirable byproduct.
When methyl mercaptan or dimethyl disulfide is employed as a reactant to produce a methane sulfonyl halide, the amount of undesirable byproducts is minimal. However, when higher-alkyl mercaptans or higher-alkyl disulfides are employed as reactants to produce higher-alkane sulfonyl halides, the quantity of undesirable byproducts, such as alpha-chlorinated byproducts, is greatly increased. The presence of such undesirable byproducts causes the process to be less efficient and can necessitate the implementation of expensive separation processes and equipment.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a more efficient process for preparing higher-alkane sulfonyl halides.
A further object of the present invention is to provide a process for preparing higher-alkane sulfonyl halides which inhibits the formation of at least one undesirable byproduct.
Other objects and advantages of the present invention will become more apparent as the invention is more fully disclosed hereinbelow.
In accordance with the present invention, there is provided a process for preparing higher-alkane sulfonyl halides comprising contacting a sulfur-containing compound, a halogen-containing compound, and a phase transfer agent within a reaction zone under conditions sufficient to produce a higher-alkane sulfonyl halide.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term “higher-alkane” means an alkane having 2 or more carbon atoms, preferably 2 to 20 carbon atoms.
It has been discovered that, in a process for producing higher-alkane sulfonyl halides by reacting a sulfur-containing compound and a halogen-containing compound, the presence of a phase transfer agent during such reaction inhibits the production of certain undesirable byproducts.
Thus, in accordance with an embodiment of the present invention, a sulfur-containing compound, a halogen-containing compound, and phase transfer agent are contacted within a reaction zone under reaction conditions sufficient to produce a higher-alkane sulfonyl halide.
The sulfur-containing compound employed in the process of the present invention can generally be represented by the formula RSX, wherein X is hydrogen or a radical of the formula SR
1
and where R is an alkyl group having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, and R
1
is an alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. R and R
1
can be the same or different alkyl groups, but are preferably the same. The alkyl groups may be branched or straight-chained and may also be substituted alkyl radicals having such substituent atoms and groups as hydroxyl, chlorine, bromine, fluorine, amine (NH
2
), sulfonic acid (SO
3
H), sulfonyl chloride (SO
2
Cl), and SO
3
R. However, the alkyl groups are preferably not substituted directly with halogens. More preferably, both alkyl groups, R and R′, are unsubstituted.
Preferred sulfur-containing compounds include ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, n-butyl mercaptan, n-hexyl mercaptan, cyclohexyl mercaptan, n-octyl mercaptan, n-nonyl mercaptan, n-decyl mecaptan, n-dodecyl mercaptan, diethyl disulfide, di-n-propyl disulfide, di-iso-propyl disulfide, di-n-butyl disulfide, di-iso-butyl disulfide, di-n-hexyl disulfide, di-iso-hexyl disulfide, di-n-octyl disulfide, di-iso-octyl disulfide, and combinations of any two or more thereof. More preferably, the sulfur-containing compound is n-propyl mercaptan, n-octyl mercaptan, di-n-propyl disulfide, di-n-octyl disulfide or a combination of two or more thereof. Most preferably, the sulfur-containing compound is n-octyl mercaptan.
The halogen-containing compound employed in the process of the present invention can be any halogen-containing compound suitable for reacting with the sulfur-containing compound to produce the desired alkane sulfonyl halide product of this invention. Preferably, the halogen of the halogen-containing compound is chlorine or bromine, but more preferably it is chlorine. Most preferably, the halogen-containing compound is chlorine (Cl
2
).
The amount of halogen-containing compound employed in the process of the present invention can be the stoichiometric amount suitable for reacting with the sulfur-containing compound to yield the desired alkane sulfonyl halide. Generally, the weight ratio of halogen-containing compound to sulfur-containing compound employed in the present inventive process is from about 1:10 to about 100:1, but can be from about 1:2 to about 20:1, or from about 1:1 to about 8:1, or from 2:1 to 4:1.
The sulfur-containing compound and halogen-containing compound are preferably contacted within a reaction zone in the presence of an aqueous hydrogen halide. Preferably, the aqueous hydrogen halide comprises hydrochloric acid, hydrobromic acid, or a mixture thereof. Most preferably, the aqueous hydrogen halide comprises hydrochloric acid. The weight of the hydrogen halide as a percentage of the total weight of the aqueous hydrogen halide is preferably from about 5 weight percent to about 80 percent, more preferably from about 10 to about 50 percent, more preferably from about 20 to about 40 percent, most preferably from 25 to 35 percent.
The amount of aqueous hydrogen halide employed in the process present invention can be any amount which is effective to produce the desired alkane sulfonyl halide product. Preferably, the amount of aqueous hydrogen halide is such that the weight ratio of the hydrogen halide in the aqueous hydrogen halide to the sulfur-containing compound is from about 1:25 to about 50:1, more preferably from about 1:5 to about 10:1, and most preferably from 1:3 to 6:1.
Generally, the phase transfer agent employed in the process of the present invention comprises one or more compounds capable of inhibiting the formation of undesirable byproducts and promoting the yield of desired sulfonyl halide.
A preferred phase transfer agent for use in the reaction system of the instant invention is selected from the group consisting of alkoxylated compounds, quaternary ammonium salts, alkali metal alkyl sulfates, alkali metal salts of alkanoic acids, alkali metal salts of alkaryl sulfonic acids, 1-alkyl pyridinium salts, and combinations of two or more thereof.
The presently preferred phase transfer agent is an alkoxylated compound. Examples of suitable alkoxylated compounds include, but are not limited to, alkoxylated alcohols, alkoxylated mercaptans, sulfates of alkoxylated alcohols, alkoxylated phenols, sulfates of alkoxylated phenols, and combinations of two or more thereof.
An alkoxylated alcohol useful in the present invention has a general formula of R
2
O[CH
2
CH(R
3
)O]
q
H where R
2
is a C
1
-C
20
hydrocarbyl radical selected from the group consisting of alkyl radical, alkylaryl radical, aryl radical, cycloalkyl radical, alkenyl radical, and combinations of two or more the
Phillips Petroleum Company
Stewart Charles W.
Vollano Jean F.
LandOfFree
Process for the preparation of higher-alkane sulfonyl halides does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the preparation of higher-alkane sulfonyl halides, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of higher-alkane sulfonyl halides will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2932253