JPH11116522A - Novel ether compound, foam inhibitor and low foam detergent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel ether compound having sufficient defoaming property and detergency, good alkali resistance and good biodegradability, and a method for producing the same. SOLUTION: The polyoxyalkylene dialkyl ether represented by the general formula (I), a method for producing the same, a foam inhibitor comprising the same, and a low-foaming detergent composition containing the same. R ¹ O- (EO) _x- (PO) _y- (EO) _z -R ² (I) wherein R ¹ and R ² are an alkyl group having 1 to 24 carbon atoms or a cyclo group having 3 to 12 carbon atoms. An alkyl group, EO is an oxyethylene group, PO is an oxypropylene group, x and z are numbers of 1 or more,
y is a number from 1 to 4. Note that (EO) _x , (PO) _y , and (EO) _z are block-connected in this order. ]

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel ether compound, a process for producing the same, a foam inhibitor comprising the same, and a low-foaming detergent composition containing the same. The present invention relates to a novel polyoxyalkylene dialkyl ether useful as a detergent or a foam inhibitor, a method for producing the same, a foam inhibitor comprising the same, and a low-foaming detergent composition containing the same.

[0002]

2. Description of the Related Art Undesirable foaming of household or industrial cleaning agents during washing in automatic dishwashers, cans and bottles, glass washing, etc., occurs. In some cases, low-foaming detergents or foam inhibitors have been added.

[0003] Low-foaming detergents include copolymers of ethylene oxide and propylene oxide or alkylene oxide adducts of aliphatic alcohols (addition of ethylene oxide to aliphatic alcohol followed by propylene oxide or butylene oxide). And the like containing a methyl etherified compound are known.

As a foam inhibitor, an adduct of an aliphatic polyalcohol and propylene oxide (West German Patent No. 128)
No. 0455) is known. However, these compounds are not sufficiently biodegradable to meet current legal regulations, and compounds having a hydroxyl group do not have sufficient stability against alkalis required for general washing and the like.

[0005] Further, West German Patent No. 3,315,951 discloses that polyethylene glycol dialkyl ether has sufficient biodegradability, high stability to alkali, high detergency and low foaming property. However, when the terminal alkyl group or alkenyl group of the polyethylene glycol dialkyl ether has a low carbon number (for example, carbon number 4), it is not sufficiently satisfactory as a low foaming property, and a high carbon number (for example, carbon number 8). Although it has high detergency and low foaming properties, it is manufactured using higher alkyl halides, so it is difficult to produce it economically. I have.

[0006]

Under such circumstances, the present inventors have conducted intensive studies and as a result, have found that they have a sufficient defoaming effect and a cleaning effect, exhibit high stability against alkalis, and have a satisfactory effect. The present inventors have found an inexpensive novel ether compound having excellent biodegradability and a method for producing the same, and have completed the present invention.

That is, the present invention relates to a compound represented by the general formula (I): R ¹ O- (EO) _x- (PO) _y- (EO) _z -R ² (I) wherein R ¹ and R ² are the same or different. Differently, having 1 to 24 carbon atoms
A linear or branched alkyl group of 3 to 12 carbon atoms
EO represents an oxyethylene group, PO
Represents an oxypropylene group. x and z are each 1 or more numbers indicating the average addition mole number of ethylene oxide, and y is a number of 1 to 4 indicating the average addition mole number of propylene oxide. Note that (EO) _x , (PO) _y , and (EO) _z are block-connected in this order. A polyoxyalkylene dialkyl ether represented by the formula (1), a method for producing the same, a foam inhibitor comprising the same, and a low-foaming detergent composition containing the same.

The biodegradability of the ether compound of the present invention is BO
It has a D (biochemical oxygen demand) of 80% or more, and is a good biodegradable compound without any legal regulations. In addition, the production method of the present invention does not have the drawback of producing a large amount of waste, which is essentially involved in the conventional Williamson method, and contaminating the product with a halogen compound. It has the feature that it does not require the use of an ether compound and can be produced at low cost. Further, since the ether compound of the present invention is obtained by a reaction essentially using no halogen compound, the problem of coloring hardly occurs and the stability over time is excellent.

[0009]

Embodiments of the present invention will be described below in detail.

The ether compound of the present invention is represented by the above general formula (I). In the general formula (I), a linear or branched chain having 1 to 24 carbon atoms represented by R ¹ and R ^2. Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, henycosyl , Docosyl, tricosyl, tetracosyl and other linear alkyl groups, isopropyl, isobutyl, ethylhexyl, methylheptyl, ethylheptyl, methylnonyl, methylundecyl, methylheptadecyl, hexyldecyl, octyldecyl, trimethylhexyl and other branched alkyl groups Lifting It is possible, preferably an alkyl group having a linear or branched chain of 4 to 18 carbon atoms. Specific examples of the cycloalkyl group having 3 to 12 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, 4-methylcyclohexyl, and the like, with a cyclohexyl group being preferred.

Among them, R ¹ is preferably a straight-chain or branched-chain alkyl group having 8 to 18 carbon atoms, and R ² is preferably a straight-chain or branched-chain alkyl group having 4 to 12 carbon atoms. Octyl groups are preferred.

In the general formula (I), x and z each represent an average number of moles of ethylene oxide of 1 or more, and the sum of x and z is preferably 5 to 50, more preferably 10 to 20. Are particularly preferred. Y is a number of 1 to 4 indicating the average number of moles of propylene oxide added,
A number of 1-2 is preferred. Further, those in which the sum of x and z is equal to or less than the sum of the carbon numbers of the alkyl groups of R ¹ and R ² are preferable particularly when used as a foam inhibitor.

The polyoxyalkylene dialkyl ether represented by the general formula (I) of the present invention is represented by the general formula (II): R ¹ O- (EO) _x- (PO) _y- (EO) _z -H (II) (Wherein, R ¹ , EO, PO, x, y and z have the above-mentioned meanings) and a polyoxyalkylene monoalkyl ether represented by the general formula (III)

[0014]

Embedded image

(In the formula, R ³ and R ⁴ are the same or different and each represent a hydrogen atom or a linear or branched alkyl group having 1 to 23 carbon atoms, and the total number of carbon atoms of R ³ and R ⁴ is 23 or less. And R ³
And R ⁴ may together form a ring. In the case where the carbonyl compound represented by the formula (1) or the carbonyl compound is an aldehyde compound, it can be produced by reacting the polymer under a hydrogen atmosphere using a catalyst.

The polyoxyalkylene monoalkyl ether represented by the general formula (II) used in the present invention is represented by the general formula (IV) R ¹ -OH (IV) (wherein R ¹ has the same meaning as described above). ), Ethylene oxide, then propylene oxide,
Further, it can be obtained by sequentially adding ethylene oxide in blocks.

Specific examples of the alcohol represented by the general formula (IV) include methyl alcohol, ethyl alcohol, propyl alcohol, n-butyl alcohol, n-pentyl alcohol, n-hexyl alcohol, n-heptyl alcohol and n-heptyl alcohol. Octyl alcohol, n-nonyl alcohol, n-decyl alcohol, n-undecyl alcohol, n-dodecyl alcohol, n-tridecyl alcohol, n-tetradecyl alcohol, n-pentadecyl alcohol, n-hexadecyl alcohol, n- Linear alcohols such as octadecyl alcohol and n-eicosyl alcohol, isopropyl alcohol, isobutyl alcohol, 2-ethylhexyl alcohol, 2-hexyldecyl alcohol, 2-heptylundecyl alcohol, 2-octyldode Alcohol, 2-decyl tetradecyl branched alcohols, such as alcohols, cyclopropanol, cyclobutanol, cyclohexanol, cycloalkanols such as cyclooctanol and the like.

When the carbonyl compound represented by the general formula (III) or the carbonyl compound used in the present invention is an aldehyde compound, its polymer (hereinafter simply referred to as carbonyl compound) includes paraformaldehyde, formaldehyde Acetaldehyde, paraacetaldehyde, propylaldehyde, n-butyraldehyde, isobutyraldehyde, pentylaldehyde, hexylaldehyde, 2-ethylbutyraldehyde, heptylaldehyde, octylaldehyde, 2-ethylhexylaldehyde, nonylaldehyde, isononylaldehyde, decylaldehyde, Aldehydes such as undecylaldehyde, dodecylaldehyde, hexadecylaldehyde, octadecylaldehyde, eicosylaldehyde,
Acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, pinacolone, methyl-n-amyl ketone, methyl-n-hexyl ketone,
Diethyl ketone, ethyl-n-butyl ketone, di-n-
Examples thereof include ketones such as propyl ketone, diisopropyl ketone, diisobutyl ketone, cyclohexanone, 2-methylcyclohexanone, cyclopentanone, and cycloheptanone.

Among these carbonyl compounds, aldehydes are preferable, and aldehydes having 4 to 12 carbon atoms, especially butyl aldehyde, isobutyraldehyde, octyl aldehyde, isononyl aldehyde, and decyl aldehyde are preferable.

In the present invention, the polyoxyalkylene monoalkyl ether represented by the general formula (II) and the general formula (I)
Examples of the catalyst used in the reaction of the carbonyl compound represented by II) include carbon, alumina, silica, a palladium catalyst supported on alumina or silica, palladium hydroxide or palladium oxide, and the like, particularly supported on carbon powder. Palladium catalysts are preferred.

The catalyst is preferably used in an amount of 0.1 to 10% by weight, based on the polyoxyalkylene monoalkyl ether (II) used, as long as the catalyst is supported at 5% by weight based on the carrier. % By weight is more preferred. The catalyst can be used in all pH ranges, but preferably at pH 2
~ 8 catalysts are preferred. Here, the pH of the catalyst refers to the pH of the aqueous solution when 2 g of the catalyst powder is dispersed in 30 g of ion-exchanged water.

In the production method of the present invention, the polyoxyalkylene monoalkyl ether (II) and the carbonyl compound
The reaction molar ratio of (III) can be appropriately set, but is preferably polyoxyalkylene monoalkyl ether (II): carbonyl compound (III) = 1: 1 to 1:50. This reaction is carried out in a hydrogen atmosphere, and the hydrogen pressure is 1 to 25 since an appropriate reaction rate is obtained and the reduction of the carbonyl group is small.
0 kg / cm ² is preferable, and 1 to 150 kg / cm ² is more preferable. Further, the condition may be such that the hydrogen partial pressure is substantially 1 kg / cm ² or less such that hydrogen flows under atmospheric pressure. Reaction temperature is 10 ~
200 ° C is preferred, and 50-190 ° C is more preferred. The reaction time is preferably 3 to 25 hours, more preferably 3 to 15 hours.

In the reaction of the polyoxyalkylene monoalkyl ether represented by the general formula (II) with the carbonyl compound represented by the general formula (III), the desired compound represented by the general formula (I) is used. Equimolar water is produced together with the ether compound, but it is preferable to carry out the reaction while removing this water, since the reaction is accelerated. Specific methods for removing water include a method of removing water by performing a reaction in the presence of a dehydrating agent, a method of removing water while passing a gas such as hydrogen, and a method of removing water by azeotropic dehydration. There is a method such as a method of leaving. Among these methods, a method of removing water while flowing hydrogen is preferable, and a method of removing water by-produced by the reaction out of the system while flowing hydrogen using a reactor equipped with a dehydration tube is particularly preferable. . In the method of removing water while flowing hydrogen outside the system, the flow rate of hydrogen may be appropriately selected according to the scale of the reaction. For example, a flow rate of 1 liter is preferably 0.01 to 30 liter / min. In addition, the flow of hydrogen may be continuous or intermittent during the reaction, but continuous flow is preferable in order for the reaction to proceed smoothly.

In the method of removing water by carrying out the reaction in the presence of a dehydrating agent, specific examples of the dehydrating agent used include anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous calcium sulfate, anhydrous calcium chloride, molecular sieve Among them, anhydrous magnesium sulfate is preferable. The amount of the dehydrating agent varies depending on the type of the dehydrating agent to be used. For example, when anhydrous magnesium sulfate is used, the amount is preferably 0.05 to 2 times mol based on the polyoxyalkylene monoalkyl ether (II).
0.1 to 1 mole is preferable.

In the present invention, when reacting the polyoxyalkylene monoalkyl ether (II) with the carbonyl compound (III), the carbonyl compound (III) may be charged together with the polyoxyalkylene monoalkyl ether (II). The reaction may be carried out while at least a part of the carbonyl compound (III) is dropped into the reaction system. When an aldehyde is used as the carbonyl compound (III), the reaction is preferably performed while at least a part of the aldehyde is dropped into the reaction system. This is because when the aldehydes are charged at once, the selectivity of the aldehydes is not always high, and it may be necessary to remove the aldol condensate.

In the present invention, the dropwise addition of the carbonyl compound to the reaction system refers to not only the case where the carbonyl compound is continuously added to the reaction system at a constant rate little by little but also the case where the carbonyl compound is added intermittently to the reaction system. included.
The method of dropping is not particularly limited, but it is sufficient that the carbonyl compound is added separately in the reaction system, and it is preferable to perform the reaction by controlling the dropping rate of the carbonyl compound with a pump or the like.

In the present invention, when the polyoxyalkylene monoalkyl ether (II) is reacted with the carbonyl compound (III), the reaction can be carried out without using a solvent, but in a form diluted with an appropriate solvent. Can also be used. Examples of such solvents include, for example, n-pentane,
Inert organic solvents such as n-hexane, n-heptane, n-octane, n-decane, hydrocarbon solvents such as petroleum ether, ether solvents such as dibutyl ether and dihexyl ether can be used, It is not necessarily limited to these.

The polyoxyalkylene dialkyl ether represented by the general formula (I) of the present invention obtained by the above-mentioned method has sufficient defoaming properties and detergency, and shows high stability to alkalis. It is very useful as a foam inhibitor and can be preferably used as an active ingredient of a low foam detergent.

The low-foaming detergent composition of the present invention is characterized by containing the polyoxyalkylene dialkyl ether represented by the general formula (I). The content of the polyoxyalkylene dialkyl ether (I) is preferably 0.01 to 50% by weight,
10% by weight is more preferred.

The low-foaming detergent composition of the present invention comprises, in addition to the polyoxyalkylene dialkyl ether (I), components commonly used in detergents, such as wetting agents, builders, complexing agents, alkalis, acids, preservatives, It may contain a microbial agent, an organic solvent and the like.

Examples of the wetting agent contained in the low-foaming detergent composition of the present invention include nonionic surfactants such as aliphatic alcohols, alkylphenols, aliphatic amines and fatty acid amides and ethylene oxide adducts thereof, fatty acids, and the like. Examples of the anionic surfactant include an alkyl metal salt of an acid such as an alkyl sulfate, an alkyl sulfonic acid, and an alkyl benzene sulfonic acid, an amine salt, and an alkylolamine salt.

The builders and complexing agents contained in the low-foaming detergent composition of the present invention include alkali metal orthophosphates, polymer phosphates, silicates, and the like.
Examples include borate, carbonate, polyacrylate, gluconate, citric acid, ethylenediaminetetraacetic acid and the like.

The detergent composition of the present invention has low foaming properties and excellent detergency, and is required to have low foaming properties such as washing with an automatic dishwasher, cans and bottles, and glass. It is particularly useful as

[0034]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples and Examples, but the present invention is not limited to these Examples. The percentages in the examples are on a weight basis unless otherwise specified.

[0035] Production Example 1 Formula (1) Production of polyoxyalkylene dodecyl octyl ether represented by _{CH 3 (CH 2) 11 0-} (EO) 7 - (PO) 1.5 - (EO) 7 - (CH 2) ₇ CH ₃ (1) 5 equipped with a hydrogen gas inlet tube, stirrer,
In a 00 ml reaction vessel, ethylene oxide (average addition mole number: 7 moles), propylene oxide (average addition mole number: 1.5 moles), and ethylene oxide (average addition mole number: 7 moles) were added to n-dodecyl alcohol in this order. 150 g of the obtained polyoxyalkylene monododecyl ether
(0.17 mol), 5% Pd-C as catalyst (pH = 6.6)
6 g, and 28.3 g of octyl aldehyde (0.22 g) were continuously supplied under atmospheric pressure at a flow rate of 0.3 L / min.
Mol) was added dropwise at a rate of 2.8 g / hr, and the mixture was stirred at 150 ° C. for 12 hours.

After completion of the reaction, the catalyst was removed by filtration, excess octylaldehyde was distilled off under reduced pressure, and 160.2 g of the target polyoxyalkylenedodecyloctyl ether (hereinafter abbreviated as ether compound (1)) was obtained in a colorless and transparent state. Obtained as a liquid. The degree of etherification of the polyoxyalkylene monododecyl ether was 99%. FIG. 1 shows the ¹ H-NMR spectrum of the obtained ether compound (1), and FIG. 2 shows the infrared absorption spectrum.

The preparation of polyoxyalkylene dodecyl octyl ether represented in Production Example 2 Formula _{(2) CH 3 (CH 2} ) 11 0- (EO) 2.5 - (PO) 1.5 - (EO) 3 - (CH 2) ₇ CH ₃ (2) Equipped with a hydrogen gas inlet tube, stirrer and dehydration reflux device
In a 00 ml reaction vessel, ethylene oxide (average addition mole number 2.5 moles), propylene oxide (average addition mole number 1.5 moles), and ethylene oxide (average addition mole number 3 moles) were added to n-dodecyl alcohol in this order. The obtained polyoxyalkylene monododecyl ether 150
g (0.29 mol), 5% Pd-C (pH = 6.6
) Charge 6g, and supply hydrogen at 0.3 liter / min under atmospheric pressure
52.0 g of octyl aldehyde while continuously circulating with
(0.41 mol) at a rate of 5.2 g / hr and 150 ℃
For 12 hours.

After completion of the reaction, the catalyst was removed by filtration, excess octylaldehyde was distilled off under reduced pressure, and 175.6 g of the desired polyoxyalkylenedodecyl octyl ether (hereinafter abbreviated as ether compound (2)) was obtained in a colorless and transparent state. Obtained as a liquid. The degree of etherification of the polyoxyalkylene monododecyl ether was 99%.

[0039] Production Example 3 formula (3) represented by polyoxyalkylene dodecyl octyl ether in Production _{CH 3 (CH 2) 11 0-} (EO) 5 - (PO) 4 - (EO) 5 - (CH 2) ₇ CH ₃ (3) Equipped with a hydrogen gas inlet tube, a stirrer, and a dehydration reflux device.
In a 00 ml reaction vessel, n-dodecyl alcohol was added with ethylene oxide (average addition mole number: 5 moles), propylene oxide (average addition mole number: 4 moles), and ethylene oxide (average addition mole number: 5 moles) in this order. 150 g of the obtained polyoxyalkylene monododecyl ether
(0.17 mol), 5% Pd-C as catalyst (pH = 6.6)
6 g, and 30.5 g (0.24 g) of octyl aldehyde was continuously supplied under atmospheric pressure at a flow rate of 0.3 L / min.
Mol) was added dropwise at a rate of 4.5 g / hr, and the mixture was stirred at 170 ° C. for 10 hours.

After completion of the reaction, the catalyst was removed by filtration, excess octylaldehyde was distilled off under reduced pressure, and 160.1 g of the objective polyoxyalkylenedodecyl octyl ether (hereinafter abbreviated as ether compound (3)) was obtained in a colorless and transparent state. Obtained as a liquid. The degree of etherification of the polyoxyalkylene monododecyl ether was 99%.

[0041] Production Example 4 Expression of polyoxyalkylene dodecyl octyl ether represented by (4) Production _{CH 3 (CH 2) 11 0-} (EO) 7 - (PO) 2 - (EO) 6 - (CH 2) ₇ CH ₃ (4) Equipped with a hydrogen gas inlet tube, a stirrer and a dehydration reflux device.
In a 00 ml reaction vessel, ethylene oxide (average addition mole number: 7 moles), propylene oxide (average addition mole number: 2 moles), and ethylene oxide (average addition mole number: 6 moles) were added to n-dodecyl alcohol in this order. 160 g of the obtained polyoxyalkylene monododecyl ether
(0.18 mol), 5% Pd-C (pH = 6.6) as a catalyst
Charge 6.4 g, and supply hydrogen at 0.3 liter / min under atmospheric pressure
32.3 g of octylaldehyde (0.
25 mol) at a rate of 4.5 g / hr and 10
Stirring was performed for hours.

After completion of the reaction, the catalyst was removed by filtration, excess octylaldehyde was distilled off under reduced pressure, and 177.5 g of the objective polyoxyalkylenedodecyl octyl ether (hereinafter abbreviated as ether compound (4)) was obtained in a colorless and transparent state. Obtained as a liquid. The degree of etherification of the polyoxyalkylene monododecyl ether was 99%.

Examples 1 to 4 and Comparative Examples 1 to 3 The ether compounds (1) to (4) obtained in Production Examples 1 to 4 and the comparative ether compounds shown below were used as foam inhibitors and the following components were used. Was mechanically mixed to prepare a storable powdery low-foaming detergent composition for dishwashing.
The detergency, low-foaming property and alkali resistance of the obtained low-foaming detergent composition were evaluated by the following methods. Table 1 shows the results.

[0044] <ether compounds compared> Comparative Product _{1 CH 3 (CH 2) 11} 0- (EO) 20 (CH 2) 2 CH 3 Comparative Product _{2 CH 3 (CH 2) 11} 0- (EO) 5 (CH _{2) 2} CH ₃ Comparative product _{3 H- (PO) 20 - (} EO) 15 - (P
O) _20- H <Composition of low-foaming detergent> Ether compound 2% Sodium hydroxide 40% Sodium tripolyphosphate 20% Sodium sulfate 38% <Evaluation method of detergency and low-foaming property> The detergent composition was placed in a cartridge container for supplying the detergent, and set in an automatic dishwasher DW-230L manufactured by Sanyo Electric Co., Ltd. A cleaning agent was supplied from this supply machine, and a cleaning test was performed under the following conditions, and the detergency and low foaming property were evaluated based on the following criteria.

Test conditions Washing temperature: 60 ± 2 ° C. Washing time: 45 seconds Detergent concentration: 0.15% Rinsing time: 15 seconds Rinse temperature: 80 ± 2 ° C. Washing object: Commercial dish 20 Sheet.

Detergency The detergency was evaluated by visually checking the residual spots of salad oil, and evaluated according to the following criteria. ：: 0 to 5 spots are observed. Δ: 6 to 19 spots were observed. X: 20 or more spots are recognized.

Low Foaming The height of foaming in the automatic dishwasher was measured and evaluated according to the following criteria.

○: Foam amount is small (foaming height is less than 1.5 cm) △: Foam amount is normal (foaming height is 1.5 cm or more and less than 4 cm) ×: Foam amount is large (foaming height is 4 cm) <Evaluation Method for Alkali Resistance> The powdered detergent composition prepared as described above was left at 50 ° C. for one month, and the coloring condition after one month was visually determined, and evaluated according to the following criteria. ○: No coloring ×: Coloring

[0049]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a ¹ H-NMR spectrum of a polyoxyalkylenedodecyl octyl ether obtained in Production Example 1.

FIG. 2 is an infrared absorption spectrum of the polyoxyalkylenedodecyl octyl ether obtained in Production Example 1.

Continued on the front page (72) Inventor Susumu Yamazawa 1334, Minato, Wakayama-shi, Wakayama Pref.

Claims (8)

[Claims] 1. A compound of the general formula (I) R ¹ O- (EO) _x- (PO) _y- (EO) _z -R ² (I) wherein R ¹ and R ² are the same or different Numbers 1-24
A linear or branched alkyl group of 3 to 12 carbon atoms
EO represents an oxyethylene group, PO
Represents an oxypropylene group. x and z are each 1 or more numbers indicating the average addition mole number of ethylene oxide, and y is a number of 1 to 4 indicating the average addition mole number of propylene oxide. Note that (EO) _x , (PO) _y , and (EO) _z are block-connected in this order. A polyoxyalkylene dialkyl ether represented by the formula: 2. In the general formula (I), R ¹ has from 8 to 8 carbon atoms.
18 linear or branched alkyl groups, R ² having 4 to 12 carbon atoms
2. The polyoxyalkylene dialkyl ether according to claim 1, wherein the sum of x and z is 5 to 50, and y is a number of 1 to 2. 3. The polyoxyalkylene dialkyl ether according to claim ¹ , wherein the sum of x and z is equal to or less than the sum of the carbon numbers of the alkyl groups of R ¹ and R ² . 4. The general formula (II) R ¹ O- (EO) _x- (PO) _y- (EO) _z -H (II) (wherein R ¹ , EO, PO, x, y and z are A polyoxyalkylene monoalkyl ether represented by the general formula (III): (Wherein, R ³ and R ⁴ are the same or different and each represents a straight or branched chain alkyl group having a hydrogen atom or a C 1 to 23, R ³
And R ^{4 have} a total carbon number of 23 or less. R ³ and R ⁴ may be combined to form a ring. 4. The method according to claim 1, wherein, when the carbonyl compound represented by the formula (1) is an aldehyde compound, the polymer is reacted under a hydrogen atmosphere using a catalyst. A method for producing a polyoxyalkylene dialkyl ether. 5. A foam inhibitor comprising the polyoxyalkylene dialkyl ether according to claim 1. 6. A polyoxyalkylene dialkyl ether obtained by the method according to claim 4.
A foam inhibitor as described. 7. A low-foaming detergent composition comprising the polyoxyalkylene dialkyl ether according to any one of claims 1 to 3. 8. The low-foaming detergent composition according to claim 7, which comprises the polyoxyalkylene dialkyl ether obtained by the method according to claim 4.