Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Reexamination Certificate
2000-06-19
2002-04-23
Shaver, Paul F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C514S063000
Reexamination Certificate
active
06376696
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to formulations comprising quaternary ammonium compounds substituted by a trialkoxysilane group, hereinafter called siloxane quats for short, and special solvents and also to the preparation and use of these siloxane quat formulations.
There is extensive patent literature relating to the preparation of quaternary ammonium compounds having a trialkoxysilane substituent and one or two fatty alkyl radicals and to the use of these compounds as biocides. The trialkoxysilane substituent augments the tendency of quaternary ammonium compounds to form permanent finishes on surfaces of various kinds, for example textiles composed of polyamide, cotton or polyester, wood, paper, glass, plastics or metals. The surfaces finished with these compounds acquire durable water-resistant antimicrobial protection as a result. For instance, a solution of 3-(trimethoxysilyl)propyloctadecyl-dimethylammonium chloride in methanol is commercially available for the antimicrobial finishing of various surfaces.
EP-A-0 108 853 describes the preparation of 3-(trimethoxysilyl)propyl-didecylmethylammonium chloride from 3-chloropropyltrimethoxysilane and didecylmethylamine without solvent or in a solvent such as methanol. Without further details being provided, solvents useful for bactericidal or fungicidal applications are said to be water, water-miscible solvents such as alcohols, for example methanol, ethanol and butanol, methylcellosolve, ethylcellosolve and ketones such as methyl ethyl ketone. For textile treatment, solvents such as hydrocarbons, chlorinated hydrocarbons, ethers and benzene are said to be alternatively useful.
WO-87/06587 discloses preparing compounds of the type
by reacting tertiary amines with 3-chloropropyltrialkoxysilanes under alkali metal iodide catalysis. The solvent for this catalytic reaction is selected from certain glycol ethers.
Further quaternary ammonium compounds, including some substituted by trialkoxysilane radicals, are recited in U.S. Pat. No. 4,883,917. They are prepared at 50-100° C. either without solvent or in the solvents used in many examples, ethyl acetate, methyl ethyl ketone and para-dioxane. Further possible solvents for quaternization reactions are said to be tetrahydrofuran, dimethoxyethane and diglyme.
EP-A-0 415 540 describes using quaternary ammonium compounds substituted by trialkoxysilane radicals for the antibacterial and fungicidal finishing of textile fabrics to eliminate odor. The preferred compound is 3-(trimethoxysilyl) propyloctadecyl-dimethylammonium chloride. A method for preparing these compounds is not disclosed, although there is a reference to the prior art.
K. J. Hüttinger, Chemiker-Zeitung, 111 (1987) pages 213-220 describes the use of quaternary trialkoxysilane for preparing carrier-bound agents for disinfecting water. With this technique, unlike chlorination or ozonization, say, no active compound passes into the water. The quaternary trialkoxysilanes are synthesized in methanol or ethylene glycol monomethyl ether at 110° C. in an autoclave.
The solvents which in the above-described prior art are used during the reaction of haloalkyltrialkoxysilanes with tertiary amines or are mixed in after the reaction have the drawback—which weighs heavily in the textile industry in particular—of having low flash points and being highly flammable. Many of the solvents hitherto used, for example methanol, have a boiling point below the reaction temperatures, so that their use requires that the reaction be carried out under elevated pressure, and this naturally requires increased expenditure on apparatus and safety. Quaternary ammonium compounds having trialkoxysilane substituents are usually solids, depending on the alkyl chain length. Since solids are more costly to handle and meter than liquids, most users prefer liquid formulations.
SUMMARY OF THE INVENTION
It is an object of the present invention to develop liquid siloxane quat formulations that do not have the disadvantage of having a low flash point and being highly flammable. The solvents used shall be compatible with the siloxane quats, shall augment the end use and shall have favorable ecotoxicological properties. It is desirable, but not absolutely necessary, for them also to be useful as solvents during the reaction of haloalkyltrialkoxysilanes with tertiary amines. It is a further object to develop a siloxane quat formulation which, even at low concentration, is superior to the prior art with regard to activity against microorganisms such as bacteria and fungi on textile surfaces in particular.
These objects are achieved by the process of the invention for preparing the siloxane quat formulations of the invention using specific glycol ethers or specific dialkylglycols as solvents.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention accordingly provides a process for preparing an antimicrobial formulation by reacting a compound of the formula 1
(R
1
O)
3
Si—(CH
2
)
3
—X (1)
with a compound of the formula 2
(H
3
C)NR
2
R
3
(2)
where
R
1
is C
1
-C
4
-alkyl
R
2
is C
8
-C
20
-alkyl
R
3
is methyl or C
8
-C
20
-alkyl
X is Cl or Br,
excluding iodides, in a molar ratio of (1):(2)=1:0.9 to 1:1.4,
which comprises conducting said reaction in a solvent conforming to the formula 3
where
R
4
is C
1
-C
4
-alkyl
R
5
is H or methyl
R
6
is H or methyl
m is 2, 3, 4 or 5,
subject to the proviso that when m is 2 R
4
and R
6
are not both methyl, and not removing this solvent after said reaction, or adding this solvent after said reaction.
The invention further provides an antimicrobial formulation obtainable by the process described above.
In a preferred embodiment of the invention, R
1
is methyl. X is preferably chlorine.
In a further preferred embodiment, R
2
is C
10
-C
18
-alkyl, especially C
12
-C
16
-alkyl, specifically a mixture of C
12
-, C
14
- and C
16
-alkyl radicals.
In a further preferred embodiment, R
3
is C
8
-C
16
-alkyl or methyl. R
3
is particularly preferably methyl when R
2
is C
12
-C
18
-alkyl, especially when R
2
is C
14
-alkyl.
In a further preferred embodiment, R
4
is methyl. R
5
is preferably hydrogen. R
6
is preferably hydrogen. m is preferably 3 or 4.
The process of the invention is preferably carried out at temperatures of 100 to 140° C. Temperatures of 110 to 130° C. are particularly preferred.
The process is preferably carried out under a dry protective gas in the absence of water. The water content of the solvents should preferably be below 0.1%. Highly suitable solvents are dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dimethyltetraglycol, dimethylpolyglycbl having an average molar mass of about 200-350 g/mol. Particularly highly suitable are butyldiglycol, methylpolyglycol having an average molar mass of about 200-350 g/mol, and especially methyltriglycol and/or methyltetraglycol. These solvents are compatible with siloxane quats, augment the end use as antimicrobial formulations, possess favorable ecotoxicological properties and do not have the disadvantage of low flash point and high flammability. The reaction of haloalkyltrialkoxysilane with tertiary amine can be carried out in the presence of the abovementioned solvents, but it is preferable to conduct the reaction in the absence of these solvents and to add them only after the reaction has taken place, at a temperature at which the products of the reaction are still liquid. When siloxane quat formulations are prepared in the presence of solvents, small amounts of alcohol may be eliminated from the alkoxy group of the haloalkyltrialkoxysilane. These small amounts of alcohol can, if desired, be removed, for example by distillation or stripping under reduced pressure.
A particularly preferred siloxane quat formulation is prepared by reacting 3-chloropropyltrimethoxysilane and tetradecyldimethylamine in a molar ratio of 1:1 to 1:1.1 at 120° C. (±10° C.) without solvent and adding methyltriglycol after the reaction has taken place.
The formulation of the invention includes at least one sil
Bender Walter
Raab Klaus
Clariant GmbH
Silverman Richard P.
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