CA2011316A1

CA2011316A1 - Prevailingly liquid detergent and/or bleaching compositions containing low molecular weight tertiary amines in the form of n-oxide

Info

Publication number: CA2011316A1
Application number: CA002011316A
Authority: CA
Inventors: Agostino Fantoni; Fulvio Burzio
Original assignee: Ausimont SpA
Current assignee: Solvay Specialty Polymers Italy SpA
Priority date: 1989-03-09
Filing date: 1990-03-07
Publication date: 1990-09-09
Also published as: IT8919708A0; EP0387049A3; EP0387049A2; JPH02272099A; IT1229564B

Abstract

ABSTRACT OF THE DISCLOSURE
Prevailingly liquid detergent and/or bleaching compositions, containing low molecular weight tertiary amines in the form of N-oxide.

Description

~ 3 The invent1on relates to prevail~ngly liquid detergent and~or bleaching compos~tions, containing low molecular weight ter~iary amines, for example triethanol-amine; the invention relates in particular to water-based liquid detergent compositions usually utilized for autom atic washing machines, as are ~escribed for example in British patent No 7 2,197,340.
The water-based 1iquid detergents for washing machines at present in commerce have compositions, ~hich can be substantially divided into two classes :

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. -- 2 (a) clear compositions, consisting of highly concentrated solutions of surface-active matters, which do not con-tain water softeners wherefore they are defined as "non-built" compositions; these compositions exhibit a rather low viscosity (below 500 mPa.s at room tem-perature)and usually contain triethanolamine (TEA), generally as aneutralizer of the acid components and/or as a solubilizer of the surface-active compoundsj (b~ milky compositions, which contain low csncentrations of surface-active components and considerable amounts of water softeners (for example zeolites 4A, generally present in the form of suspensions) and which are therefore defined as "built" compositionsi such compositions exhibit relatively high viscosities (high-er than 1,000 mPa.s at room temperature).
Both the "built" products and the "non-built"
products do not contain any stain-removing (bleaching) com-ponent and, contrary to what happens with the detergents for washing machines (in powder), they do no~ exhibit any satisfactory activity inthe stain removal (chemical bleach-ing~ and therefore provide lower performanees.
~ t is generally assumed that this not negligible inferiority of the liquid detergents as compared with the corresponding products in powder can be overcome merely by 3~ f5 adding to the liquid, as washing besins, the usual bleaching additives based, for example, on perborate, percarbonate, hypochlorite and the like, either activated or non activat-ed.
It is an object of the present invention to provide novel liquid detergent and/or bleaching compositions.

Accordingly, Ln its broadest aspect, the invention rel-ates to prevailingly liquid detergent and/or bleaching com-positions containing at least a low molecular weight tertiaryamine in the form of N-oxide,.selected ~rom the group consisting of:
a) trialkanolamines, in the form of N-oxide, having formula :
/ ROH
O=N / ROH (I) \ ROH
where groups R, same or different from .eachother.,are straight or branched alkylene groups having from 1 to 4 C
atoms;
b) trialkylamines, in the form of N-oxide, having formula :
/ R' O=N - R' (II) \ R' where groups R', like or different from one another,are straight or branched alkyl groups having 1 to 4 C
atoms;
c) a heterocyclic compound selected from : tri-3~L~

ethylenediamine N-oxide, triethylenediamine N,N'-dioxide, N-methyl-~orpholine N-oxide, N-methyl-piperidine N-oxide.
For example, if the commonly used triethanolamine (TEA) is replaced in the liquid ~non-built~ detergents, by the respective ,~-oxide ~TEAO) of formula (III):
(HO-CH2-CH2-)3-N=O (III) the obtained bleaching levels are comparable, the conditions being equal, with what is obtained with the liquid "built"
detergents and with the powder detergents; the use of said N-oxide ~III) does not involve particular technological pro-blems and it can be proportioned in the same manner as tri-ethanolamine. As TEAO does not possess the alkalinity of TEA, the neutralization of the acid components of the liquid de-tergent(fatty acids, alkylbenzenesulphonic acid etc.), which is usually carried out with TEA, can be completed, in the presence of TEAO, with NaOH or, even better, with KOH, with-ut jeopardizing the solution homogeneity; the use of potashcaustic instead of~soda permits to obtain a higher stability of the liquid detergent compositions at lower temperatures. If amine is not fully replaced . by N-oxide, the alkali amount can be advantageously reduced.
T h e Applicant has surprisingly observ-ed that the same bleaching results, at the doses suggest-ed for the bleaching agents, are obtained only with the li-- 5 ~ 3.~

quid detergents of the "bui1t" type, while with the non-built" products the stain-removal action of the additive, for example perborate, is negligigle, so that in practice the addition of same is nearly useless. If one considers that the use of liquid detergents for washing machines has great possibilities of development and that the detergent compositions of the "non-built" type are the most widely utilized, the inefficiency of the latter of exerting ableach-ing action (not even with the addition of bleaching agents which have proved to be highly effective on otheroccasions) represents a serious problem.
Thus, an aspect of the present invention permi~ the bleaching agents to exert their stain -removing ac-tion also in the presence of liquid detergents of the non-~built type and, by consequence, to permit that also with such detergents bleaching effects may be obtained when the conventional bleaching additives are added at the suggested doses. The Applicant has now succeeded in properly modifying the compositlon of the ~lnon-builtl' liquid detergents, by el-iminating the inhibiting action exerted by the latter on the bleaching agents.

According to the known technique, N-oxides are ob-tainable for example by oxidation of the corresponding tertia-ry amines with hydrogen peroxide. Said oxidation may occur 2~ ~3~i with H202 either in defect or in excess. The synthesis of N-oxides with an excess of hydrogen peroxide results, on con-clusion of the reaction, in the presence of residual traces of H202, the amount thereof being dependent on the utilized excess; for example, if the H202 excess amounts to 10%, the residue obtained amounts from 0.5 to 1% by weight referred to the reaction rnixture. Failing suitable modifications, this type of synthesis prevents therefore an immediate evapor ation of the solvent, due to the inherent explosion risk, and/or a direct -utilization of the reaction mixture in the preparation of the liquid detergents, with serious technolo-gical complications in both cases.
Somebody has suggested to eliminate the residual H202 by MnO2, which is considered an excellent agent ~or H202 decomposition without N-OXIDE damage.-----------------------However, the use of MnO2 is not possible in practice; in fact~

________________________- even after a careful filtration, -thatiS already a complex operation in itself, small -traces of MnO2 remain in the N-OXIDE and by consequence also ih the detergents containinX it; so these residues can exert their decomposition effect --------- ----_________________________ --------------- also on the bleach-ing peroxides which are added to the liquid detergents during the washing cycle thereby drastically reducing the perform-ances thereof.

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Other techniques, such as e.g. heating, are not ad-visable because the N-oxides, in general, decompose at temper-atures higher than 60C; also metals (for example Fe or Cu),which are known for their degradation action on H202, are not utilizable, because they are also efficacious in causing the degradation of N-oxides and, in many aspects, are undes-irable during the detergents utilization step.
The Applicant has noted that if the hydrogen per-oxide amount is maintained below the stoichiometric values, it is possible to obtain a practically H202-free product, im~
mediately ready for use in the detergents formulations (and for water evaporation, if a concentrated N-oxide is desired);
the thus obtained product contains little amounts of tertiary amine not convertedd intoN-oxide, which do not impair at all the bleaching power and, on the contrary, make the detergent formulability easier. Generally, a H202amount ranging from 70% to 99~ of the stoichiometric value is recommended.
The presence of unconverted amine is furthermore balancing the lower alkalinity of the corresponding N-oxide, therefore the lesser neutralizing power, with respect to the fatty acids, Dromotes thedetergent homogeneity and reduces the al-kali amount,necessary to brins the formulate to a prefixedpH value.
The present description~ examples included, refers 3~`~
in detail to the use of triethanolamine (TEA), either free or salified (for example with fatty acids or alkylbenzene sulphonic acids), at least partially converted lo the cor-responding N-oxide (TEAQ); the scope of the invention, how-ever, includes other types of low molecular weight tertiary amines and in particular triethylamine, triethylenediamine (PABCO), N-methylmorpholine, N-methylpiperidine etc. The repl~cements of the amines by the corresponding N-oxides does not adversely affect the storage stability of the de-tergent even at low temperatures, at high humidity values and during long stretches of time.
Oxidation of tertiary amines with hydrogen per-oxide can be conducted on the amines as such, on the salts thereof with fatty acids (TEA soaps) or with other acid compounds, or also on a liquid detergent w~ich contains the amine, by adding H202 to said detergent.
The follo~ing examples are given for a merely il-lustrative purposes, without limiting in any way the scope of the invention.
Example 1 (test with H202 in excess) N-oxide of triethanolamine (TEAO) was synthesised by reaction between triethanolamine and hydrogen peroxide, according to the scheme :
(HO-CH2-CH2)3 N + H2 2 (HO-CH2-CH2)3-N + 2 2~3~;
g Into a 2-neck, 1,000 cm flask, equipped with a bulb cooler, 150 9 o~ triethanolamine (TEA), 300 9 of water and 150 mg of EDTA (sodium ethylenediaminetetraacetate)were poured; the mixture was heated at 55~C by means of an outer water bath, whereafter 111 9 of H202 a~ 33.8% by weight, cor-responding to about 10% of H202 in excess, with respect to the stoichiometric value, were gradually introduced (by us-ing a dropping funnel). The addition rate was such as to maintain the temperature below 60C; on conclusion of the addition, temperature was maintained at 55C for 90 minutes.
Residual H202 was allowed to spontaneously decompose in the course of a few days, and subsequently the product was dried by evaporation of water (in a rotary evaporator under vacuum) at a temperature not exceeding 40C. A dry residue of about 165 g, corresponding to a practically quantitative yield, was obtained.
Example 2 (test with H202 in defect) Example 1 was repeated reducing the amount of hy-drogen peroxide (at 33.8%) to 103 9, an amount equivalent to about 98% of the stoichiometric value; the final product was analyzed,as to H202, by means of the paper method (PEROXID-TEST; MERKOQUANT 1011) and the analysis result was negative. No appreciable traces of residual H20? were found. I

Example 3 (concentrated N-oxide) In order to obtain amoreconcentrated TEA0, without resorting to one or more water evaporation steps, ex-ample 1 was repeated, eliminating the 300 9 of water (added in example 1 as a reaction solvent) and directly re-acting TEA with H202. In particular: 111 g of H202 at 33.~%
by weight were added at 55C to 150 9 of TEA, whereafter the temperature ~Jas maintained at 55C for 2 hours. An aque-ous solution at about 67% by weight of TEA0 wasthus obtained, this value being much higher than the N-oxide concentration obtained in example 1 (29%).
Example 4 In order t.o check theinfluence of theinvention on the bleach dng power of the liquid "non-built" detergents, when a bleach-ing agent is added to the latter, bleaching tests in a com-mercial-type washing machine REX (mod. RF 224X) were conduct-ed under the following conditions :
washing water: tap water at 16F hardness;
at 60C (maximum suggested temperature for liquid detergents);
laundry load: 3 kg (for each washing) of white and clean cot-ton cloth + two lOxlO cm cotton test pieces EMPA 114 supplied by EMPA Institute, standard stained Wi th red wine;

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detersive dose: 180 9 for each washing (average dose recom-mended by the manufacturers);
bleaching agent dose: ~0 9 -for each washing (average dose recommended by the manufac-turers).
As a bleaching agent a commercial product (product I) based on sodium monohydrate perborate (PBS-l) and on activator (TAED = tetraacetyl ethylenediamine)was used-The composi-tion of the bleacher was -the following:
PBS-l = 47%; TAEb = 13%;
fillers and minor components = the balance to 100%.
As liquid detergents, a "built" type com-mercial product tproduct II), a non-built type commercial product (product III), a laboratory-reproduced formulate hav-ing a composition similar to said product III (as to the most importantcomponents,TEA included) and an analogous formul-ate, also reproduced in laboratory, in which TEA had been were compared replaced by N-oxide (TEA0~ e last two formulates are indicated in Table 1 as III/TEA and III/TEAO, respectively.

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T A B L E

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Components PROD.CT ~ PROD.CT III/TEA III/TEAO

______________ I -t A nionic ll surfactants I7.5% 1 13.7% ,14.0%ll 14.0%
Non-ionic ¦ ~ i surfactants ¦2.8% ~ 10.7% 11.0%11.0%
Coconut fatty acids 13.3% 13.0%13.0%
Zeolite 4A 25.1% _ _ Ethyl alcohol 8.0% lO.OX10.0%
Glycerine 7.5% _ TEA 10.0% 10.0%10.0%
TEAO 10.0%
Water and minor additives (*) bal.to 100 bal.to 100 bal.to 100 bal.to 100 (*) bal = balance Formulates III and III/TEA exhibited a pM value ranging from 8 to 8.5, while .formulate II had a pH value equal to about 10; formulate III/TEAO had a pH value equal to 6.8, due to the lower alkalinity of TEAO in comparison with TEA. For the purposes of the invention, the pH of formulate III/TEAO was brought to a value of 8-8.5 (namely to the value of the "non-- 13 ~ 3~
-built" detergents) by addition of NaOH. The addition of NaOH,in order to adjust the pH value,is a usual step in the formulation of the liquid detergents, also in the absence of TEAO, and therefore it does not affect the validi~y of the invention. In the washing machine tests, the following comb-inations (delergent ~ b1eaching agents) were used :
A PRODUCT II alone B PRODUCT II + bleaching additive C PRODUCT III alone D PRODUCT III + bleaching additive E III/TEA + bleaching additive F III/TEAO + bleaching additive.
The obtained bleaching results are reported hereinafter and express the per cent removal (D) of bleachable dirtiness (red wine), calculated as follows :
D = c b x 100, where :
a = whiteness of the test-piece washed during the test;
b = whiteness of the test-piece prior to washing;
c = whiteness of the not stained test-piece.
Whiteness was measured by means of reflectometer Elrepho-Zeiss, in comparison with MgO, assumed as a blank (whiteness = 100), using filter No. 6. The results are recorded on Table 2.

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._ Formulate Removal of bleachable stains (%) .. _ _ .
A 2 9 . 1 B 7 2 . O
C 48.7 D 5 0 . 6 E 4 ~ . 2 F 7 8 . 1 ~ -These data prove that the addition of bleaching agents to liquid detergents leads to the expected bleaching effect only in the case of "built"detergents (see cases A and B) which do not contain TEA, while it does not lead to ap-preciable effects when the liquid detergent is of the~hon-built"type (see cases C and D). Furthermore, these data prove that the substitution of TEA by TEAO, in the'hon-built"detergents, results in a marked improvement of white-ness (see cases E and F), bringing it again to the values obtainable with the built formulates.
Example 5 . _ Further bleaching tests were carried out by adding to a non-built liquid detergent a bleaching mixture consist-ing of sodium perborate monohydrate (PBS-l) and of TAED

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in a practically stoichiome-tric ratio ~about 48% of PBS-l and about 52% of TAED). The tests were conducted in a 500 cm3 f1ask, adding to 250 cm3 of deionized water, brought to 60C, 7 9 of liquid detergent and 0.7 9 of the bleaching mixture; finally, two 5x5 cm test-pieces of cotton EMPA
stained 114--~r-~ with red wine (as in ex-4) wel8 ~ U$dter 1 hour, during ~Ihich time the test-pieces were kept at a constant temperature of 60C and under stirring, the test-pieces were rinsed in running water, dried, ironed and subject-ed to whiteness determination as described in example 4.
As detergents, another commercial li-quid product (PRODUCT IY), a laboratory reproduced formulate having acompOSition similar to PRODUCT IY in the essential com-(product IV/TEA)ponents, TEA included ~ and a formulate like the pre-eding one, where TEA had been replaced by TEAO (form-were compared ulate IY/TE ~ ; the weight percentages of the components re indicated in Table 3.

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Components PRODUCT IV IV/TEA
Linear sodium alkyl-benzenesulphonate (LAS) 11.3% 11.3%~11.3%
Sodium lauryl sulphate 3.2% 3.2% 3.2%
Alcohol ~C12-C13), etho- I
xylated with 7 n;oles of EO ~ 13.7% 13.7% 13.7%
Cocunut fatty acids 7.0% 7.0% 7.0%
Ethyl alcohol 9.0% 10.0% 10.0%
TEA 5.0% 5.0%
TEAO 5.0~
Water and minor additives ba-i.to 100% bal.to 100~ bal.tr lOOX

The bleaching tests were carried out using the following combinations :
A PRODUCT IV alone B PRODUCT IV + bleaching additive C IV/TEA + bleaching additive D IV/TEAO + bleaching additive The bleaching results are shown in Table 4.

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~ 17 -r Formula-te Dirtiness removal (%) A 51 . 2 B 5 2 . 9 C 49.5 D 80.6 ...._ These tests prove that also for a different~non-built'form-ulate (PRODUCT IY), the action of the bleaching agent is negligible if TEA is present in the detergent, while it is fully exerted when the corresponding N-oxide is present.
Exarnple 6 Example 4 was repeated with liquid~hon-built"form-ulations, additioned, at the moment of washing, with a com-mercial bleaching product (PRODUCT I) (and having a basic com-position like composition III/TEA of example 4) and with other formulations in which TEA had partially bæn repla ced by TEAO, maintaining the sum TEA+TEAO constant, acoord-ing to the scheme of Table 5.

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-Formul ate Wei ght rati o ( TEA : TEAO ) A 1 : O

C 7 : 3 D 5 : 5 E 3 : 7 F 1 : 9 Where necessary, the pH of the formulates was brought to 8-8.5 with NaOH; the bleachin~ results, evaluated and expressed as in example 4, are indicated in Table 6.

Formulate stain removal (%) A + PRODUCT I 34.1 B + ~ 35.6 C + ~ 36.4 D + ~ 46.7 E ~ " 69.9 F ~ " 76.3 :
. G + ~ 78 1 _ , 9 ~ 3~;
.
These tests show that good bleaching performances are ob-tainable even if TEA is partially replaced by TEAO; al-ready with TEAO amounts corresponding to mixture TEA/TEAO
in a 30:70 ratio, the results obtained are decidedly su-perior than theones found with TEA alone.
Example 7 Formulates A-G of example 6 were subjected to a low temperature stability test,in order to ascertain pos-sible precipitations or demixing as the inner temperature of the detergent.decreases. In particular, the formulates were gradually cooled by immersin9 them into an ice bath, till reaching an inner temperature of +3 C, then they were maintained at such temperature for 30 minutes. The results of the visual observations are reported on Table 7.

Formulate Appearance A Limpid,homogeneous B ll ll C ll ll D

E

F

G

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This proves that the use of TEAO instead of TEA does not adversely affect the storage stability of the formulates at low temperatures.
Example 8 A series of formulates containing mixtures of TEA ----- and TEAO was prepared on the basis of the IV/TEA
described in examp1e 5, bringing all the formulates to a pH value of 8-8.5 with NaOH (where necessary) and ~aintain-ing the sum TEA ~ TEAO constant as in example 7. The deter-gents were then subjected to a low-temperature storage test, as is described in example 7, maintaining the products at ~2C for 30 minutes. The results are reported on Table 8.

Formulate TEA/TEAO ratio Formulate appearance A 1 : O limpid and homogeneous B 8 2 ;; ;; ';

E 2 : 8 F O : 1 Example 9 In the preparation of the liquid~non-built"formul ates it may be sometimes preferable to utilize, as a start-3~;21 -ing material, the TEA salt of the coconut fatty acids (TEA
soap) instead of the fatty acids and TEA separately, as usually occurs. This does not represent, in itself, a hin-drance to the replacement of TEA by TEA0; in fact, the test described hereinafter proves that also the TEA soap reacts with H202 to p~ovide TEA0.
Description of the test:
Into a two-neck flask having a 1,000 cm3 volume, equipped with a bulb cooler, there were charged 180 9 of TEA soap (from coconut fatty acids), 500 9 of H20 and 100 mg of EDTA;
the mass was brought to 55C and 55 9 of H202 at 33.8% by weight were gradually added without exceeding 60C; the temperature was then maintained at 55C for about 90 minutes. The oc-curred conversion of TEA to TEA0 was evidenced by the fact that the solution passed from the limpid state (before re-action) to a cloudy and gelatinous state. That was due to the reduced alkalinity of TEA0 in comparison with TEA and to the consequent 1 o w e r neutralizing activity ex-erted on the fatty acid, which at the en~ of the re-action was therefore (partially) present in the water-ins-oluble free acid form.
Example 10 -The conversion of TEA to TEA0 can be carried out also using a liquid (TEA-containing) detergent, by adding to said detergent a suitable ~22 amount. To 100 9 of li-quid detergent IiI/TEA, described in example 4, brought to 55C in a two-neck, 250 cm flask, equipped with a bulb cooler, 6.~ cm3 of H202 at 33.8~o by weight were gradually added (without exceeding 60C)i after the ad-dition, the temperature was maintained at 55C for 150 minutes, whereafter the pH of the detergent was brought to a value of 8-8.5 by means of NaOH. To ascertain that the reaction had really occurred, the detergent so treated (freed from the residual H202 traces) was utili~ed to car-ry out a bleaching test according to the modalities des-cribed in example 5, using as a blank a commercial deter-gent (PRODUCT III ) . In particular, 5.3 9 of detergent~dis-solved in 250 cm3 of distilled water (at 60C)J were additione under stirring, with 0.7 9 of a bleaching mixture, describ-ed in example 5, consisting of PBS-l (48%) and TEAO (52%) and furthermore, immediately after, with two 5x5 cm test--pieces of cotton EMPA 114, stainedwith red wine. After 60 minutes the two test-pieces were rinsed in running water, air-dried, ironed, and subjected to whiteness determination, as described in example 4; the bleaching values were as follows :
Formulate Removed stain .
PRODUCT III 57.5 III/TEA + H202 80.9 - - 23 - ~ 3~
., These tests prove the occurred replacement of TEA by TEAO
in the III/TEA detergent treated with H202.
Example 11 The liquid non-built detergents containing TEAO
instead of TEA can be brought to the pre-established pH
value, usually 8-8.5, either with NaOH or with KOH. However, when KOH is used, the formulate acquires an even higher sta-bility at low temperatures. The following test is a proof thereof: the III/TEA composition of example 4 was brought to a pH = 8.2 with KOH and was subjected to the stability test at low temperatures described in example 8; said composition remained limpid and homogeneous up to a temperature of -1C.

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Claims

1. Prevailingly liquid detergent and/or bleaching com-positions containing low molecular weight tertiary amines in the form of N-oxide, selected from the group comprising :
a) trialkanolamines, in the form of N-oxide, having formula (I) :

(I) where groups R, same or different from eachother, are straight or branched alkylene groups having 1 to 4 carbon atoms;
b) trialkylamines, in the form of N-oxide, having formula (II) :

(II) where groups R', same or different from eachother are straight or branched alkyl groups having 1 to 4 carbon atoms;
c) a heterocyclic compound selected from :
triethylenediamine N-oxide, triethylenediamine N,N'-dioxide,N-methyl-morpholine N-oxide, N-methyl-piper-idine N-oxide.

2. The compositions according to claim 1, in which the tertiary amine, in the form of N-oxide, is triethanol-amine N-oxide of formula :

3. The compositions according to claim 1, in which the tertiary amine, in the form of N-oxide, is selected from : triethylenediamine N-oxide, triethylenediamine N,N'-dioxide, N-methyl-morpholine N-oxide, N-methyl--piperidine N-oxide, triethylamine N-oxide.

4. The compositions according to anyone of the preceding claims, containing also NaOH. or KOH, as a pH regulator.

5. The compositions accordingto anyone of the preceding claims, containing, besides the tertiary amine in the form of N-oxide, also the tertiary amine in a free (non-oxidized) form, the ratio :

ranging preferably from 70:30 to 99:1 by weight.

6. Use of low molecular weight tertiary amines, and in particular of the amines specified at points a), b), c) of claim 1, in their N-oxide form, optionally in admixture with the corresponding tertiary amines in the free form, for obtaining water-based liquid detergent compositions of the "non-built"type, to be used in wash-ings in automatic washing machines.

7. A process of preparing a composition according to anyone of claims 1 to 5, characterized in that the selected tertiary amine is converted into the corresponding N-oxide, by reaction with hydrogen peroxide, and that the result-ing N-oxide is added to the other components of the com-position.

8. A process of preparing a composition according toanyone of claims 1 to 5, characterized in that the selected tertiary amine is added in the free form to the other components of the composition and it is then converted "in situ" into the corresponding N-oxide by reaction with hydrogen peroxide.

9. The process according to claim 7 or 8, in which the H2O2 amount is in defect with respect to the stoichiometric amount.

10. The process accordingtoanyone claims 7 to 9, charact-erized in that oxidation to N-oxide is carried out on the corresponding tertiary amine in the salified form (with acid components, such as e.g. fatty acids or al-kylbenzene-sulphonic acids).
Novara, Cio.lf