JP2719613B2 - Antibacterial agent - Google Patents

Description

The present invention relates to a silyl group-containing compound, and more particularly to an antibacterial agent comprising a silyl group-containing amphoteric surfactant.

[Technical background]

Generally, amphoteric surfactants have the feature of having a broad antibacterial spectrum, and therefore, amphoteric surfactants
For example, for the disinfection and cleaning of fingers, instruments and hospital rooms in the medical field, for the cleaning and disinfection of equipment, bottles and bats in the food processing and fermentation industry, and for the cleaning and disinfection of instruments and barns in the dairy farm. Widely used.

[Problems to be solved by the invention]

However, conventionally known antibacterial agents comprising an amphoteric surfactant can provide an excellent antibacterial effect during cleaning and disinfecting treatments, but thereafter have a low durability of adhesion to an object, and therefore water and other substances. Repeat to
Alternatively, in the case where the antibacterial agent is continuously contacted, the antibacterial agent has a disadvantage that the antibacterial agent separates from the object and the antibacterial effect is significantly reduced in a short time.

[Object of the invention]

The present invention solves the above-mentioned drawbacks of the conventional antibacterial agent composed of an amphoteric surfactant, has a high durability of adhesion to an object, and is continuously applied to water or the like when repeatedly subjected to washing. It is an object of the present invention to provide an antibacterial agent that maintains an excellent initial antibacterial effect for a long period of time even when it is contacted.

[Configuration of the invention]

The antibacterial agent of the present invention has a general formula R ¹ M ¹ QM ² _n G wherein R ¹ represents a hydrophobic monovalent hydrocarbon group, and Q represents an alkylene group having 1 to 7 carbon atoms or phenylene. M ¹ and M ² are the same or different from each other, ｛R ² is a hydrogen atom or R (R is an alkyl group or a phenyl group having 4 or less carbon atoms); A ¹ is -Z-COOH (Z is an alkylene group or a substituent having an alkyl group, an alkenyl group or an aryl group. substituted alkylene group), a ² is -Z-COO ^-. (Z is as defined above), a ^{3 _{is, -Y-SiR 3 a (OR}} 4) 3-a (Y is the number of carbon atoms is 1 ~
8, a divalent hydrocarbon group (may have a —COO— or —O— group), R ³ represents an alkyl group, R ⁴ represents an alkyl group or an acyl group, and a represents 0, 1 or 2; is there. )
Represents G is a group selected from R ² , A ¹ , A ² and A ³ (R ² , A ¹ , A ² and A ³ are as defined above), n is 1 to 4 Wherein at least one group represented by A ¹ or A ² is present in the molecule, and at least one group represented by A ³ is present. Further, a nitrogen atom present in the molecule may form a salt with hydrogen halide. ] It comprises the silyl group containing compound represented by these.

[Action]

The antibacterial agent of the present invention is basically an amine compound having a carboxyl group and has characteristics as a so-called carboxylic acid-type amphoteric surfactant. Because it is a compound that also contains, by the silyl group, not only physically attached to the substrate to which the application is applied, but also chemically bonded and attached, and due to this excellent adhesion,
Great durability is obtained and the antibacterial effect is maintained for a long time.

 Hereinafter, the present invention will be described specifically.

The antibacterial agent of the present invention can be manufactured as follows. That is, a specific amine compound (1) represented by the following formula (1) is combined with a specific silane compound (2) represented by the formula (2) and a specific carboxylic acid (3) represented by the formula (3). It can be produced by reacting.

Amine compound (1) As the amine compound (1), a compound represented by the formula (1) Is used. Here, R ¹ is a hydrophobic monovalent hydrocarbon group, and examples thereof include an alkyl group having 4 to 20 carbon atoms (for example, a butyl group, an octyl group,
Lauryl group), aryl group, aralkyl group (for example, benzyl group, chlorobenzyl group, phenylbenzyl group,
Examples thereof include a diphenylmethyl group), a polyoxyalkylene group (preferably a polyoxypropylene group is preferred), and a compound represented by the following formula.

(Wherein, R ⁵ and R ⁶ are each a hydrogen atom or a carbon number of 1 to 20)
Represents an alkyl group, an aryl group, an aralkyl group or a polyoxyalkylene group, and R ⁷ represents an alkyl group having 1 to 20 carbon atoms, an aryl group, an aralkyl group or a polyoxyalkylene group. In addition, one of the three R ² in the formula (1) is always a hydrogen atom, and the other two R ² are a hydrogen atom and an alkyl group having 4 or less carbon atoms (eg, a methyl group, an ethyl group, and a propyl group). Etc.) or a phenyl group, which may be the same or different from each other.

Q represents an alkylene group or a phenylene group having 1 to 7 carbon atoms, and n is an integer of 1 to 4.

This amine compound (1) comprises a halide or epoxy compound, acrylate or methacrylate of a corresponding group (R ¹ ), Can be obtained by reaction with the compound represented by Further, alkylamino compounds of various carbon number 8 to 18 or the formula C ₁₈ H ₃₇ NHCH compound represented by ₂ CH ₂ NH ₂ and the like are commercially available.

As the amine compound (1), for example, It is preferable to use a reaction product of a compound represented by the formula (1) with an alkyleneamine such as diethylenetriamine. This reaction is known and can be carried out, for example, by mixing an excess of alkyleneamines and heating to about 180 ° C.

Examples of the amine compound (1) include the following.

In each formula, R represents an alkyl group having 4 or less carbon atoms or a phenyl group; R ¹ and Q are as described above;
-CH ₂ The CH ₂ - or -CH ₂ CH ₂ CH ₂ - is preferred.

Since R ^{1 of} this amine compound (1) is a hydrophobic group, affinity for the surface of bacteria is secured,
The conditions under which an excellent antibacterial effect is exhibited are set.

Silane compound (2) The silane compound (2) is an amine compound (1)
A silane compound having a functional group which reacts with an amino group or an imino group in the above, which is represented by the formula (2): Y ¹ SiR ³ _a (OR ⁴ ) _3-a Here, Y ¹ is an amino group (-N
H ₂ ) or a functional group that reacts with an imino group (NH),
As a specific example, and so on.

R ³ represents an alkyl group having 1 to 4 carbon atoms, R ⁴ represents an alkyl group or an acyl group having 1 to 4 carbon atoms, and a is an integer of 0 to 2. These preferred embodiments, -Si (OCH _{3) 3,} there is _{-SiCH 3 (OCH 3) 2,} -Si (OCH 2 CH 3) 3.

Functional carboxylic acid (3) This functional carboxylic acid (3) is an amine compound (1)
Is a functional carboxylic acid having a functional group that reacts with a primary, secondary, or tertiary nitrogen atom, which is represented by the formula (3) Z ¹ -COOH. Z ¹ represents the above functional group. Specific examples of the carboxylic acid (3), for example, wherein X-R ⁸ -COOH (wherein, X-R ⁸ represents a halogenated alkyl group, halogenated aryl group, halogenated aryl or halogenated aralkyl group And halogens include Cl, Br, etc.), α, β-unsaturated carboxylic acids, epoxy-containing alkyl carboxylic acids, and the like. Specific compounds include ClCH ₂ COOH, ClCH ₂ CH ₂ COOH, CH ₃ CHClCOOH, CH ₃ CH = CHCOO
_{H, CH 3 -CH = CH-} CH = CHCOOH, And the like. The functional carboxylic acid needs to be hydrolyzed and de-esterified by a known method after the reaction, but its alkyl ester can also be used.

After reacting the amine compound (1) with one of the silane compound (2) and the functional carboxylic acid (3), the nitrogen atom of the reaction product is reacted with the silane compound (2) and the functional carboxylic acid (3). May be reacted with the other. However, usually, it is first reacted with the silane compound (2),
It is preferable to react the reaction product with the functional carboxylic acid (3) to obtain the desired product.

Although the ratio of the amine compound (1), the silane compound (2) and the functional carboxylic acid (3) varies depending on the target compound, the molar ratio of the silane compound (2) is slightly less than 1: 1: 1. It is preferable to use an excess ratio, for example, a ratio up to about 1.5 times.

As described above, the silyl group-containing antibacterial agent according to the present invention represented by the above general formula can be obtained. Other methods, for example, the literature “New surfactant” (Hiroku Horiguchi, Sankyo Publishing Co., Ltd.,
It can also be produced using the method described on pages 575-586 of JUNE 1981.

Specific examples of preferred antibacterial agents of the present invention include: It is.

In the above, Y ² represents a reactive residue between Y ¹ and an amino group or imino group in the silane compound (2), and Z ² represents a reaction between Z ¹ and an amino group or imino group in the functional carboxylic acid (3). Indicates the residue.

Preferred Q in each formula, -CH ₂ CH ₂ - or -CH ₂ C
H ₂ CH ₂ −, It is.

The antibacterial agent of the present invention can be applied by treating the surface of the target solid or by mixing it. In actual application, the antibacterial agent can be mixed as an active ingredient with other bases, diluents, viscosity modifiers, and other components.

For example, the antimicrobial agent can be dissolved or dispersed in water, alcohol, or another hydrophilic or hydrophobic organic solvent to prepare a treatment liquid or a coating liquid. Further, for the purpose of promoting chemical attachment by silyl groups, alkali metal hydroxides, various amine compounds, γ-aminopropylsilane compounds such as N- (2-aminoethyl) -3-aminopropylsilane, fatty acid metal salts An alkali metal acetate, metal acetonate, an alkyl titanate compound or a polymer thereof, an alkyl silicate compound such as sodium silicate or a polymer thereof can be added,
Further, various mineral acids and organic acids can be used.

The antibacterial agent of the present invention can also be applied by dispersing it in a paint base composed of a synthetic resin or an emulsion thereof, and applying this to a solid surface.

〔effect〕

The antibacterial agent of the present invention is a silyl group-containing compound having characteristics as a carboxylic acid type amphoteric surfactant represented by the above general formula, so that an excellent antibacterial effect is exhibited, for example, Gram-positive bacteria, Gram-negative bacteria, Excellent antibacterial effect against molds, algae, yeast, etc., that is, antibacterial effect against bacteria, fungicidal effect, anti-algal effect, and due to silyl group, it is chemically superior to solids to which it is applied. Adhesiveness is obtained, as a result, a large durability is obtained, the antibacterial effect is maintained for a long time, for example, as understood from the description of Examples below, when applied to textiles, Excellent washing resistance is obtained.

The antibacterial agent of the present invention exerts an antibacterial effect only when the group -COOH or -COOH.HCl by the functional carboxylic acid (3) in the molecule is dissociated to -COO ^- or -COO.
H.Cl ^- is generated, and the nitrogen atom of the amino group or imino group by the amine compound (1) becomes N ⁺ to form a quaternary ammonium salt. The quaternary ammonium salt contributes to abnormal metabolism of the microorganism. It is thought to kill microorganisms.

〔Example〕

Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto.

The specifications of the high performance liquid chromatography used in the following examples are as follows.

Column: “Shim-pack PREP-ODS” (2 × 25 cm) Solvent: methanol Example 1 Synthesis of amine compound 4 mol of diethylenetriamine was placed in a four-necked flask, and heated to 180 ° C. while stirring in a nitrogen stream. Then, 1 mol of n-octyl chloride was added dropwise over 3.5 hours. The diethylenetriamine hydrochloride generated after cooling was filtered off, and the pale yellow transparent liquid was heated under a reduced pressure of 1.5 mmHg at a temperature of 123 mm.
Vacuum distillation was performed at -135 ° C to obtain 200 g (93% yield) of a colorless and transparent fraction (1).

This fraction (1) was an amine compound having the following chemical structure.

Production of CH ₃ CH _{2 7} NHCH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ Antibacterial Agent 1 5.4 g of the fraction (1) obtained as described above and its concentration
A 5.4 g methanol solution containing 40% crotonic acid was sealed in a glass ampoule and heated at 90 ° C. for 1 hour to obtain a yellow transparent liquid.

5.5 g of γ-chloropropyltrimethoxysilane
And heated at 120 ° C. for 8 hours to obtain a brown transparent viscous liquid. This solution was subjected to high performance liquid chromatography to collect a peak having a retention time of 19.11 minutes, thereby obtaining Antibacterial Agent 1 of the present invention having the following chemical structure.

Example 2 Production of Antibacterial Agent 2 5.0 g of the fraction (1), 5.1 g of γ-chloropropyltrimethoxysilane, and 4.3 g of methanol were sealed in a glass ampoule and heated at a temperature of 120 ° C. for 12 hours. A clear yellow solution was obtained. After cooling, 9.3 g of a 10% methanol solution of sodium hydroxide and 14 g of Molecular Sieves 3A (manufactured by Union Showa) were added, and the mixture was stirred for 4 hours. Molecular sieves 3A and the generated salt were separated by filtration, and the non-volatile content of the filtrate was reduced to 90%.
%, And the precipitated solid was further filtered off.

The filtrate was diluted with methanol to a nonvolatile content of 45%, and 4.7 g of the filtrate and 2.4 g of a methanol solution containing 50% monochloroacetic acid were again sealed in a glass ampoule, and the temperature was 90 ° C.
For 30 minutes to give a clear yellow solution. This solution was subjected to high performance liquid chromatography, and the retention time was 17.5.
The antimicrobial agent 2 of the present invention having the following chemical structure was obtained by collecting the peak of the present invention.

Example 3 Synthesis of amine compound Under the same molar ratio and reaction conditions as in Example 1, triethylenetetramine was reacted with n-octyl chloride, and a solid was filtered off. Vacuum distillation was performed at a temperature of 169 to 171 ° C. to obtain a colorless and transparent fraction (2).

The fraction (2) obtained here was an amine compound having the following chemical structure.

Preparation of CH ₃ CH _{2 7} NHCH ₂ CH ₂ NHCH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ Antibacterial Agent 3 4.0 g of the fraction (2) obtained as above and γ-
4.2 g of Methacryloxypropyltrimethoxysilane and 1.7 g of methanol are sealed in a glass ampoule,
Heating at 12 ° C. for 12 hours gave a clear brown solution.

A methanol solution containing 50% monochloroacetic acid
2.9 g was added, and the tube was sealed again and heated at a temperature of 90 ° C. for 10 minutes to obtain a brown transparent viscous liquid. This solution was subjected to high performance liquid chromatography, and a peak having a retention time of 21.5 minutes was collected to obtain an antibacterial agent 3 of the present invention having the following chemical structure.

Example 4 Production of Antibacterial Agent 4 5.0 g of the fraction (2), 4.2 g of γ-chloropropyltrimethoxysilane, and 4.0 g of methanol were sealed in a glass ampoule and heated at a temperature of 120 ° C. for 12 hours. A clear yellow solution was obtained.

To this solution, 7.8 g of a 10% methanol solution of sodium hydroxide and 11.6 g of molecular sieves 3A were added, and the mixture was stirred for 4 hours. Molecular sieves 3A and the generated salt were separated by filtration, the nonvolatile content of the filtrate was concentrated to a concentration of 90%, and the precipitated solid was further filtered.

The filtrate was diluted with methanol to a non-volatile concentration of 32.5%. 12.0 g of the filtrate and 1.75 g of a methanol solution containing 50% monochloroacetic acid were sealed again in a glass ampoule and heated at a temperature of 90 ° C. for 30 minutes to turn yellow. A clear solution was obtained. This solution was subjected to high performance liquid chromatography, and a peak having a retention time of 19.15 minutes was collected to obtain Antibacterial Agent 4 of the present invention having the following chemical structure.

Example 5 Synthesis of amine compound Diethylenetriamine was reacted with n-lauryl chloride under the same molar ratio and reaction conditions as in Example 1,
After the solid was filtered off, the filtrate was vacuum distilled under a reduced pressure of 2.0 mmHg at a temperature of 168 to 169 ° C. to obtain a colorless and transparent fraction (3).

The fraction (3) obtained here was an amine compound having the following chemical structure.

Preparation of CH ₃ CH _{2 11} NHCH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ Antibacterial Agent 5 5.0 g of the fraction (3) obtained as described above and γ-
4.0 g of chloropropyltrimethoxysilane and methanol
4.0 g was sealed in a glass ampule and heated at a temperature of 120 ° C. for 12 hours to obtain a yellow transparent solution.

After cooling, 7.4 g of a 10% methanol solution of sodium hydroxide and 11.1 g of molecular sieves 3A were added to the solution, and the mixture was stirred for 4 hours. Molecular sieves 3A and the generated salt were separated by filtration, the nonvolatile content of the filtrate was concentrated to a concentration of 90%, and the precipitated solid was further filtered.

The obtained filtrate was diluted with methanol to a non-volatile content of 32.7%, and 12 g of the filtrate and 1.7 g of a methanol solution containing 50% monochloroacetic acid were again sealed in a glass ampoule and heated at 90 ° C. for 30 minutes. This gave a clear yellow solution.
This solution was subjected to high performance liquid chromatography, and a peak having a retention time of 19.32 minutes was collected to obtain Antibacterial Agent 5 of the present invention having the following chemical structure.

Example 6 Synthesis of Amine Compound Iminobispropylamine and n-octyl chloride were reacted at the same molar ratio and under the same reaction conditions as in Example 1, and solids were separated by filtration. The filtrate was subjected to a reduced pressure of 1.5 mmHg. Vacuum distillation was carried out at a temperature of 135 to 137 ° C. to obtain a colorless and transparent fraction (4).

The fraction (4) obtained here was an amine compound having the following chemical structure.

Preparation of CH ₃ CH _{2 7} NHCH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ NH ₂ Antibacterial Agent 6 5.0 g of the fraction (4) obtained as described above and γ-
4.5 g of chloropropyltrimethoxysilane and methanol
4.0 g was sealed in a glass ampule and heated at a temperature of 120 ° C. for 12 hours to obtain a yellow transparent solution.

To this solution, 8.2 g of a 10% methanol solution of sodium hydroxide and 12.4 g of molecular sieves 3A were added and stirred for 4 hours. Molecular sieves 3A and the generated salt were separated by filtration, the nonvolatile content of the filtrate was concentrated to a concentration of 90%, and the precipitated solid was further filtered.

The obtained filtrate was diluted with methanol to a non-volatile content of 35.2%, and 11 g of the filtrate and 1.8 g of a methanol solution containing 50% monochloroacetic acid were again sealed in a glass ampoule and heated at a temperature of 90 ° C. for 30 minutes. This gave a brown clear solution.
This solution was subjected to high performance liquid chromatography, and a peak having a retention time of 21.32 minutes was collected to obtain an antibacterial agent 6 of the present invention having the following chemical structure.

[Experimental Examples] In the following experiments, all the treatment amounts represent the amount of the active ingredient, and all the drying was performed at 70 ° C. for 30 minutes.

Experimental Example 1 An antibacterial agent aqueous solution having a concentration of 1.0 owf% (“owf%” is a percentage by weight of the antibacterial agent with respect to the unit weight of the test cloth) using each of the above antibacterial agents 1, 4 and 6 was prepared. Preparation was performed to obtain treatment liquids, and with each of the treatment liquids, a cloth for dyeing test consisting of a cotton jersey was treated using a padding dyeing machine.

Experimental Example 2 Using each of the above antibacterial agent 2 and antibacterial agent 5, experimental example 1
In the same manner as described above, an antibacterial agent solution having a concentration of 1.0 owf% was prepared from a mixed solution in which the ratio of water and ethanol was 2: 8 to obtain a treatment solution, and a dyeing test comprising a cotton jersey was performed using each treatment solution. The raw fabric was treated in the same manner as in Experimental Example 1.

Comparative Experimental Example 1 In place of the antibacterial agent of the present invention, except that lauryl di (aminoethyl) glycine “Anon LG” (manufactured by NOF Corporation), which is a carboxylic acid-type amphoteric surfactant containing no alkoxysilyl group, was used. In the same manner as in Experimental Example 1, a cloth for dyeing test consisting of a cotton jersey was treated.

Experimental Example 3 Using the above antibacterial agent 3, a concentration of 1.0o was obtained in the same manner as in Experimental Example 1.
Prepare an antibacterial agent aqueous solution of wf%, pH7, and add
A 0% aqueous solution of sodium hydroxide was added to adjust the pH to 8, thereby obtaining a treatment liquid. In the same manner as in Experimental Example 1, a cloth for dyeing test consisting of a cotton jersey was treated in the same manner as in Experimental Example 1. .

Experimental Example 4 Using the above antibacterial agent 3, a concentration of 1.0o was obtained in the same manner as in Experimental Example 1.
A wf% aqueous solution of an antibacterial agent was prepared, and N- (2-
(Aminoethyl) -3-aminopropylsilane was added to a concentration of 0.44 owf% to obtain a treatment solution, and dyed with a cotton jersey in the same manner as in Experimental Example 1 except that this treatment solution was used. The test cloth was treated.

Experimental Example 5 Experimental Example 1 was performed using each of the above antibacterial agents 3 and 4.
A treatment solution was prepared by preparing an aqueous solution of antibacterial agent having a concentration of 1.0 owf% in the same manner as described above, and a fabric for dyeing test consisting of a polyester jersey was treated in the same manner as in Experimental Example 1 except that this treatment solution was used. did.

Comparative Experimental Example 2 In the same manner as in Experimental Example 1, except that lauryl di (aminoethyl) glycine “Anon LG”, which is a carboxylic acid type amphoteric surfactant containing no alkoxysilyl group, was used instead of the antibacterial agent of the present invention. Then, a cloth for dyeing test consisting of a polyester jersey was treated.

For each of the test cloths treated in the above experimental examples and comparative experimental examples, the sterilization rate was calculated by the shake flask method without performing the washing treatment or performing the washing treatment a predetermined number of times.

The washing process uses 0.5 g of Nissan Nonion NS-210 (manufactured by Nippon Oil & Fats Co., Ltd.) as a detergent at a ratio of 1 to water at a water temperature of 40 ° C. and a bath ratio of 1:30. Washing was carried out for 5 minutes by an electric washing machine, and thereafter, water was washed for 5 minutes while overflowing water.

The shake flask method is based on the US AATCC Test Method
100 improved methods, forcing the test cloth and bacteria into contact, creating a state similar to the state of the actual skin and bacteria,
This is a method for quantitatively measuring the antibacterial effect. In particular,
The following operations (1) to (6) are performed.

(1) 0.75 of test sample (fiber or raw cloth treated with antibacterial treatment)
Make a strip of g and use it as a test piece.

(2) A sterile phosphate buffer (70 ml) was placed in a 200 ml Erlenmeyer flask, and the bacteria Klebsiella pneumoniae ATCC4352 was added to 1.5 × 10 ^{5 to} 3 × 1.
0 Inoculate 5 ml of bacterial solution containing ⁵ cells / ml.

(3) 1 ml of the bacterial solution is collected from the Erlenmeyer flask, transferred to a test tube containing 9 ml of a sterile phosphate buffer, and uniformly mixed. 1 ml of this mixture is further mixed and diluted with 9 ml of sterile phosphate buffer. Take 1 ml of the re-diluted bacterial solution, place in a sterilized petri dish, and add 16-20 ml of tryptone glucose extract agar medium to solidify. This is cultured at a temperature of 37 ° C. for 18 to 24 hours.

(4) Put the test piece of the operation (1) into the Erlenmeyer flask in the operation (2), and insert it into the wrist action shaker
Shake for 1 hour with ist Action Shaker. Then, in the same manner as in the operation (3), the bacterial solution from the Erlenmeyer flask is directly or once or twice mixed and diluted with a sterilized phosphate buffer, transferred to a petri dish, and cultured by adding the medium.

(5) Count the number of bacteria after culturing obtained in operation (3) and operation (4), respectively, and calculate the sterilization rate according to the following equation.

(6) The same operation is performed on the same fiber or raw cloth except that the antibacterial treatment is not performed.

Table 1 shows the above results.

From the results in Table 1, it is clear that the antibacterial agent of the present invention has an excellent antibacterial effect and is excellent in washing resistance.

Claims (1)

(57) [Claims] 1. A compound of the general formula R ¹ M ¹ QM ² _n G wherein R ¹ represents a hydrophobic monovalent hydrocarbon group, and Q represents an alkylene group having 1 to 7 carbon atoms or a phenylene group. M ¹ and M ² are the same or different from each other, ｛R ² is a hydrogen atom or R (R is an alkyl group or a phenyl group having 4 or less carbon atoms); A ¹ is -Z-COOH (Z is an alkylene group or a substituent having an alkyl group, an alkenyl group or an aryl group. substituted alkylene group), a ² is -Z-COO ^-. is (Z is as defined above), a ³ is _{^{-Y-SiR 3 a (OR 4}} ) 3-a (Y is 1 to carbon atoms 8, a divalent hydrocarbon group (may have a —COO— or —O— group), R ³ represents an alkyl group, R ⁴ represents an alkyl group or an acyl group, and a represents 0, 1 or 2; ). G is a group selected from R ² , A ¹ , A ² and A ³ (R ² , A ¹ , A ² and A ³ are as defined above), n is 1 to 4 Wherein at least one group represented by A ¹ or A ² is present in the molecule, and at least one group represented by A ³ is present. Further, a nitrogen atom present in the molecule may form a salt with hydrogen halide. ] An antibacterial agent comprising a silyl group-containing compound represented by the formula: