"Modified polymeric pro-fragrance"

The present invention relates to pro-fragrance compounds obtainable by the reaction of an amino- functional polymer comprising at least one primary amine group and at least one secondary amine group with a modifier compound and subsequently an amine-reactive fragrance molecule comprising at least one ketone and/or aldehyde functionality, the production and use thereof, as well as cleaning, fabric treatment and cosmetic compositions comprising said pro-fragrance compounds.

To most consumers the smell of a cleaning, fabric treatment, cosmetic or related product as well as the smell of a substrate treated with such product is an important product feature. For instance, they often assess the performance of a laundry detergent composition not only by the visual appearance of the laundered fabric but also by the smell of the laundered fabric. Thus, a laundry detergent composition, in addition to cleaning fabric, must also provide a pleasing fragrance that is delivered to the laundered fabric during the laundering process. The same is true with regard to other cleaning, fabric treatment or cosmetic products. Hence, usually fragrance molecules or perfumes are added to such products. However, most fragrance molecules are highly volatile, which means the products and especially the substrates treated with such products loose their pleasing smell rather quickly.

To overcome this problem, it has been suggested to use so-called pro-fragrances. Pro-fragrances are compounds comprising a fragrance molecule covalently linked to a carrier which releases the fragrance molecule under defined conditions. Such pro-fragrances may be formulated by the reaction of a fragrance molecule and a compound comprising reactive groups like primary hydroxyl groups, primary amine groups and/or secondary amine groups. However, many of the known pro- fragrances are compounds of comparatively low molecular weight and hence comparatively high vapor pressure. To maintain a pleasing fragrance over a prolonged period of time it is necessary to provide pro-fragrances with reduced volatility.

US 6,790,815 B1 discloses pro-fragrances which are products of reaction between a polyamine compound, e.g. polyethyleneimines, and a fragrance molecule. In EP 1 314 777 A1 pro-perfume compositions are described which comprise the reaction product of a primary and/or secondary amine compound with certain unsaturated perfume compounds. The amine compound may be polymeric, e.g. a polyethyleneimine. Although these polymeric pro-fragrances prolong the fragrance release, e.g. from laundered fabric, they do not necessarily provide a highly noticeable fragrance immediately after the application of a product comprising such pro-fragrances to a

substrate. Thus, these perfume systems do not provide an initial good perfume performance immediately after application.

To provide an initial good perfume performance immediately after application, e.g. after the washing stage of a laundering process, and a good perfume release from the treated substrate, e.g. a dry fabric over a prolonged period of time, EP 1 451 286 B1 suggests solid particulate fabric- treatment compositions comprising two different perfume components. The first perfume component comprises a pro-perfume compound as described inter alia in US 6,790,815 B1. The second perfume component comprises a mixture of certain volatile perfume molecules and certain non-volatile molecules. Such systems are rather complex. Moreover, the solubility of the disclosed pro-perfume compounds in water is poor which makes it difficult to include them in aqueous systems.

Therefore, there remains a need to provide pro-fragrances which provide an initial good perfume performance immediately after application as well as a good perfume release from the treated substrate over a prolonged period of time, and furthermore can be easily dissolved in aqueous systems.

Surprisingly, it has been found that the above problems are overcome by pro-fragrances based on amino-functional polymers comprising both primary and secondary amine groups which are modified in a first step with a modifier, preferably a modifier providing enhanced hydrophilicity, and thereafter are reacted with an amine-reactive fragrance molecule.

Hence, a first object of the invention is a pro-fragrance compound obtainable by the reaction of

a. an amino-functional polymer comprising at least one primary amine group and at least one secondary amine group with a modifier compound comprising at least one functionality which is able to react with primary amine groups, and b. subsequent reaction of the resulting modified amino-functional polymer with an amine- reactive fragrance molecule comprising at least one ketone and/or aldehyde functionality,

wherein the modifier compound used in step a is not an amine-reactive fragrance molecule comprising at least one ketone and/or aldehyde functionality.

Due to their polymeric nature the pro-fragrance compounds of the invention have no or almost no vapor pressure which prevents their evaporation from products comprising them and from substrates treated with such pro-fragrance compounds. Moreover, the adhesion to certain substrates like textile fibers is good. This results in a good fragrance release from the treated

substrate over a prolonged period of time. Due to the modification it is possible to remarkably increase the solubility in aqueous systems and to improve the initial perfume performance immediately after application of the pro-fragrance to a substrate. Pro-fragrance compounds of the invention can be obtained very easily by simply mixing the reactants at room temperature under ambient pressure without the need of any catalyst.

Pro-fragrance compounds according to the invention are based on amino-functional polymers comprising at least one primary amine group and at least one secondary amine group.

The term amino-functional polymer as used herein shall mean compounds comprising at least one primary amine group and at least one secondary amine group which contain at least 5, preferably at least 10 repeating units. The amine groups may be part of the backbone, may be an end-group or be located on a side-chain.

Preferably, the amino-functional polymer is selected from the group consisting of polyvinylamines, alkylene polyamines and polyaminoacids, particularly preferred from alkylene polyamines.

Preferred alkylene polyamines comprise at least one primary amine group of formula (I)

-(CR ¹ R ² ) _X NH ₂ (I),

wherein x is an integer from 1 to 10, preferably from 1 to 5, particularly preferred from 2 to 3, and R ¹ and R ² , independently of each other, are H or C-|-C ₁₀ -alkyl, preferably H,

and at least one secondary amine group of formula (II)

-[(CR ³ R ⁴ ) _y NH]- (II),

wherein y is an integer from 1 to 10, preferably from 1 to 5, particularly preferred from 2 to 3, and R ³ and R ⁴ , independently of each other, are H or Ci-C,o-alkyl, preferably H.

Particularly preferred alkylene polyamines are polyethyleneimines which may be linear or branched. Preferred are branched polyethyleneimines which comprise at least one tertiary amine group in addition to at least one primary amine group and at least one secondary amine group. Particularly preferred are branched polyethyleneimines, wherein the molar ratio of primary to

secondary to tertiary amine groups is from 1 : 0.7 : 0.2 to 1 : 1.5 : 0.9, preferably from 1 : 0.85 : 0.5 to 1 : 1.1 : 0.75.

Preferably the weight average molecular weight of the polyethyleneimine is from 500 to 10000, particularly preferred from 500 to 2000.

Some useful polyethyleneimines are commercially available under the trademark Lupasol like Lupasol FG (MW 800), G20wfr (MW 1300), PR8515 (MW 2000), WF (MW 25000), FC (MW 800), G20 (MW 1300), G35 (MW 1200), G100 (MW 2000), HF (MW 25000), P (MW 750000), PS (MW 750000), SK (MW 2000000) and SNA (MW 1000000) and under the trademark Epomin like Epomin SP-103, Epomin SP-110, Epomin SP-003, Epomin SP-006, Epomin SP-012, Epomin SP- 018, Epomin SP-200. Of these, the most preferred include Lupasol FG (MW 800), G20wfr (MW 1300), FC (MW 800), G20 (MW 1300), G35 (MW 1200), G100 (MW 2000) and PR 8515 (MW 2000).

To obtain a pro-fragrance compound according to the invention the amino-functional polymer is reacted in a first step with a modifier compound comprising at least one functionality which is able to react with primary amine groups and thereby forming secondary amine groups. Preferably, stable bonds are formed which are not hydrolysable. Of course it is also possible to react the amino-functional polymer with a mixture of two or more different modifier compounds.

The modifier compound is a compound which is able to change the characteristics of the amino- functional polymer upon reaction therewith. Preferably, it is a compound comprising at least one polar and/or ionic group like a hydroxy, ether, ester or ammonium group. Such groups will alter the solubility of the amino-functional polymer, in particular increase the solubility in polar solvents like water.

It is important to point out that the modifier compound is not an amine-reactive fragrance molecule comprising at least one ketone and/or aldehyde functionality.

The modifier's functionality which is able to react with a primary amine group is preferably selected from α,β-unsatu rated carbonyl groups and/or epoxy groups.

Preferred modifier compounds are selected from compounds of formula (III), wherein

n is an integer from 0 to 40, preferably from 1 to 20, particularly preferred from 2 to 10,

R ⁵ is C ₂ -C ₄ -alkylene, preferably ethylene and/or propylene, particularly preferred ethylene, and

R ⁶ is H or Ci-C ₅ -alkyl, preferably methyl,

compounds of formula (IV)

wherein

R ⁷ is C ₂ -C ₄ -alkylene, preferably ethylene and/or propylene, particularly preferred ethylene,

R ⁸ , R ⁹ and R ¹⁰ are, independently of each other, Ci-C ₅ -alkyl, preferably methyl, and

X ^' is a suitable counter-anion like hydroxide, fluoride, chloride, bromide, iodide, methylsulfate, ethylsulfate, hydrogen sulfate, hydrogen sulfite and nitrate, preferably chloride and methylsulfate,

and/or the compound of formula (V)

The reaction can be conducted by simply mixing the amino-functional polymer and the modifier compound and stirring the mixture at room temperature and ambient pressure. In case that at least one of the educts is liquid there is no need to add a solvent. However, addition of solvent is possible, provided that the solvent does not react with any of the reactants.

Preferably, the molar amount of modifier compound used corresponds or slightly exceeds the molar amount of primary amine groups available in the amino-functional polymer. The molar ratio of modifier compound to primary amine groups is preferably from 1 : 0.9 to 1 : 1.5, particularly preferred from 1 : 1 to 1 : 1.2, more particularly preferred from 1 : 1 to 1 : 1.05.

In a second step the modified amino-functional polymer has to be reacted with at least one amine- reactive fragrance molecule comprising at least one ketone and/or aldehyde functionality. Such molecules are also called fragrance aldehydes or fragrance ketones.

All the conventional fragrance aldehydes and fragrance ketones which are typically used to achieve a pleasant fragrance perception may be used. Those skilled in the art are aware of suitable

fragrance aldehydes and fragrance ketones, which are described in US 2003/0158079 A1 paragraphs [0154] and [0155]. Furthermore, reference may also be made to US 6,861 ,402 B1.

Fragrance ketones may include all ketones that can impart a desired fragrance or a fresh perception. Mixtures of different ketones may also be used. For example, the ketone may be selected from the group comprising buccoxime, iso jasmine, methyl-β-naphthyl ketone, musk indanone, tonalide/musk plus, α-damascone, β-damascone, δ-damascone, iso damascone, damascenone, damarose, methyl dihydrojasmonate, menthone, carvone, camphor, fenchone, α- ionone, β-ionone, dihydro-β-ionone, γ-methyl so-called ionone, fleuramone, dihydrojasmone, cis- jasmone, iso-E-super, methyl cedrenyl ketone or methyl cedrylone, acetophenone, methyl acetophenone, paramethoxyacetophenone, methyl-β-naphthyl ketone, benzylacetone, benzophenone, parahydroxy-phenylbutanone, celery ketone or livescone, 6-isopropyl- decahydro-2-naphthone, dimethyloctenone, freskomenthe, 4-(1-ethoxyvinyl)-3,3,5,5-tetramethyl- cyclohexanone, methylheptenone, 2-(2-(4-methyl-3-cyclohexen-1-yl)propyl)-cyclopentanone, 1-(p- menthen-6(2)-yl)-1-propanone, 4-(4-hydroxy-3-methoxyphenyl)-2-butanone, 2-acetyl-3,3dimethyl- norbornane, 6,7-dihydro-1 ,1 ,2,3,3-pentamethyl-4(5H)indanone, 4-damascole, dulcinyl or cassione, gelsone, hexalon, isocyclemon E, methyl cyclocitrone, methyl lavendel ketone, orivon, para-tert- butylcyclohexanone, verdone, delphone, muscone, neobutenone, plicatone, veloutone, 2,4,4, 7-tetramethyloct-6-en-3-one, tetrameran, hedione and mixtures thereof. The ketones may preferably be selected from α-damascone, δ-damascone, isodamascone, carvone, γ-methylionone, iso-E-super, 2,4,4, 7-tetramethyloct-6-en-3-one, benzylacetone, β-damascone, damascenone, methyl dihydrojasmonate, methyl cedrylone, hedione and mixtures thereof.

Suitable fragrance aldehydes may be any aldehydes, which impart a desired fragrance or a fresh perception. These may again be individual aldehydes or aldehyde mixtures. Suitable aldehydes include for example melonal, triplal, ligustral, adoxal, anisaldehyde, cymal, ethyl vanillin, florhydral, helional, heliotropin, hydroxycitronellal, koavone, lauryl aldehyde, lyral, methyl nonylacetaldehyde, p-tert.-bucinal, phenyl acetaldehyde, undecylene aldehyde, vanillin, 2,6,10-trimethyl-9-undecenal, 3-dodecen-l-al, α-n-amylcinnamaldehyde, 4-methoxybenzaldhyde, benzaldehyde, 3-(4-tert-butylphenyl)propanal, 2-methyl-3-(para-methoxyphenylpropanal), 2-methyl-4-(2,6,6-trimethyl-2(1 )-cyclohexen-1-yl)butanal, 3-phenyl-2-propenal, cis-/trans-3,7-dimethyl-2,6-octadien-1-al, 3,7-dimethyl-6- octen-1-al, [(3,7-dimethyl-6-octenyl)oxy]acetaldehyde, 4-isopropylbenzaldehyde, 1 ,2,3,4,5,6,7,8-octahydro-8,8-dimethyl-2-naphthaldehyde, 2,4-dimethyl-3-cyclo- hexen-1-carboxyaldehyde, 2-methyl-3(isopropylphenyl)propanal, decylaldehyde, 2,6-dimethyl-5- heptenal, 4-(tricyclo(5.2.1.0(2,6)]decylidene-8)butanal, octahydro-4,7-methano-1 H- indenecarboxaldehyde, 3-ethoxy-4-hydroxybenzaldehyde, para-ethyl-α,α- dimethylhydrocinnamaldehyde, α-methyl-3,4(methylenedioxy)hydrocinnamaldehyde, 3,4-

methylenedioxybenzaldehyde, α-n-hexylcinnamaldehyde, m-cymene-7-carboxaldehyde, α-methyl- phenylacetaldehyde, 7-hydroxy-3,7-dimethyloctanal, undecenal, 2,4,6-trimethyl-3-cyclohexene-1- carboxaldehyde, 4-(3)(4-methyl-3-pentenyl)-3-cyclohexene carboxaldehyde, 1-dodecanal, 2,4- dimethylcyclohexene-3-carboxaldehyde, 4-(4-hydroxy-4-methylpentyl)-3-cyclohexene-1- carboxaldehyde, 7-methoxy-3,7-dimethyloctan-1-al, 2-methylundecanal, 2-methyldecanal, 1-nonanal, 1-octanal, 2,6,10-trimethyl-5,9-undecadienal, 2-methyl-3-(4-tert-butyl)propanal, dihydrocinnamaldehyde, 1-methyl-4-(4-methyl-3-pentenyl)-3-cyclohexene-1 -carboxaldehyde, 5- or 6- methoxyhexahydro-4,7-methanoindan-1- or 2-carboxyaldehyde; 3,7-dimethyloctan-1-al, 1- undecanal, 10-undecen-1-al, 4-hydroxy-3methoxybenzaldehyde, 1-methyl-3-(4-methylpentyl)-3- cyclohexenecarboxyaldehyde, 7-hydroxy-3,7dimethyloctanal, trans-4-decenal, 2,6-nonadienal, para-tolylacetaldehyde; 4-methylphenylacetaldehyde, 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1- yl)-2-butenal, ortho-methoxycinnamaldehyde, SAθ-trimethyl-S-cyclohexenecarboxaldehyde, 3,7- dimethyl-2-methylene-6-octenal, phenoxyacetaldehyde, 5,9-dimethyl-4,8-decadienal, peony aldehyde (6,10-dimethyl-3-oxa-5,9-undecadien-1-al), hexahydro-4,7-methanoindane-1- carboxaldehyde, 2-methyloctanal, α-methyl-4-(1-methylethyl)benzeneacetaldehyde, 6,6-dimethyl- 2-norpinene-2-propionaldehyde, para-methylphenoxyacetaldehyde, 2-methyl-3-phenyl-2-propen-1 - al, 3,5,5-trimethylhexanal, hexahydro-8,8-dimethyl-2-naphthaldehyde, 3-propylbicyclo[2.2.1]-hept- 5-ene-2-carbaldehyde, 9-decenal, 3-methyl-5-phenyl-1-pentanal, methylnonylacetaldehyde, 1-p- menthene-q-carboxaldehyde, citral, lilial citral, 1 -decanal, florhydral, 2,4-dimethyl-3-cyclohexene-1- carboxaldehyde, and mixtures thereof. Preferred aldehydes may be selected from cis/trans-3,7- dimethyl-2,6octadien-1-al, heliotropin, 2,4,6-trimethyl-3-cyclohexene-1-carboxaldehyde, 2,6- nonadienal, α-n-amylcinnamaldehyde, α-n-hexylcinnamaldehyde, p-tert-bucinal, lyral, cymal, methyl-nonylacetaldehyde, trans-2-nonenal, lilial, trans-2-nonenal and mixtures thereof.

For additional suitable fragrance substances selected from aldehydes and ketones, reference is made to Steffen Arctander, published 1960 and 1969, respectively, reprinted 2000 ISBN: Aroma Chemicals, vol. 1 : 0-931710-37-5, Aroma Chemicals, vol. 2: 0-931710-38-3.

As can be seen from the above examples, the fragrance aldehydes and fragrance ketones may have an aliphatic, cycloaliphatic, aromatic, ethylenically unsaturated structure or a combination of these structures. Furthermore, additional heteroatoms or polycyclic structures may also be present. The structures may have suitable substituents such as hydroxyl groups or amino groups.

Preferably the amine-reactive fragrance molecule comprising at least a ketone and/or an aldehyde functionality is selected from the group consisting of acetophenone, 4-methylacetophenone, A- methoxyacetophenone, 2-pentylcyclopentanone, jasmine, ionone, damascone and damascenone, menthone, carvone, Iso-E-Super, methyl-heptenone, cyclopentadecanone, fixolide, melonal, cymal, ethyl vanillin, helional, hydroxycitronellal, koavone, methyl-nonyl-acetaldehyde,

phenylacetaldehyde, undecylenic aldehyde, 3-dodecen-1-al, alpha-n-amyl cinnamic aldehyde, benzaldehyde, 4-methoxybenzaldehyde, piperonal, 3-(4-tert-butylphenyl)-propanal, 2-(4-tert- butylbenzyl)-propanal, 2-methyl-3-(para-methoxyphenylpropanal), 2-methyl-4-(2,6,6-trimethyl-2(1 )- cyclohexen-1-yl)butanal, cinnamaldehyde, cis-/trans-3,7-dimethyl-2,6-octadien-1-al, 3,7-dimethyl-6- octen-1-al, [(3,7-dimethyl-6-octenyl)oxy]acetaldehyde, 4-isopropylbenzaldehyde, 2,4-dimethyl-3- cyclohexen-1-carboxaldehyde, 2-methyl-3-(isopropylphenyl)propanal, decylaldehyde, 2,6-Dimethyl- 5-heptenal, alpha-n-hexylcinnamic aldehyde, 7-hydroxy-3,7-dimethyl octanal, 2,4,6-trimethyl-3- cyclohexene-1-carboxaldehyde, 1-dodecanal, 2,4-dimethylcyclohexene-3-carboxaldehyde, 4-(4- hydroxy-4-methyl pentyl)-3-cylohexene-1-carboxaldehyde, 2-methyl undecanal, 2-methyl decanal, 1-nonanal, 1-octanal, 1-heptanal, 2,6,10-trimethyl-5,9-undecadienal, 2-methyl-3-(4- tertbutyl)propanal, dihydrocinnamic aldehyde, 3,7-dimethyloctan-1-al, 1-undecanal, 10-undecen-1- al, 4-hydroxy-3-methoxybenzaldehyde, trans-4-decenal, 2,6-nonadienal, para-tolylacetaldehyde, 3,7-dimethyl-2-methylene-6-octenal, 2-methyloctanal, alpha-methyl-4-(1-methylethyl)benzene acetaldehyde, 2-methyl-3-phenyl-2-propen-1-al, 3,5,5-trimethyl hexanal, 3-propyl- bicyclo[2.2.1]hept-5-ene-2-carbaldehyde, 9-decenal, 3-methyl-5-phenyl-1-pentanal, methylnonylacetaldehyde, citral, 1 -decanal, florhydral, heliotropin, 2,4-dimethyl-3-cyclohexen-1- carbaldehyde, and mixtures thereof.

Particularly preferred amine-reactive fragrance molecules comprising at least a ketone and/or an aldehyde functionality are selected from the group consisting of acetophenone, A- methylacetophenone, 4-methoxyacetophenone, 2-pentylcyclopentanone, ionone, damascone, menthone, cyclopentadecanone, fixolide, phenylacetaldehyde, benzaldehyde, A- methoxybenzaldehyde, piperonal, 2-(4-tert-butylbenzyl)-propanal, cinnamaldehyde, 3,7-dimethyl-6- octen-1-al, alpha-n-hexylcinnamic aldehyde, 10-undecen-1-al, 1-octanal, 1-heptanal, 4-hydroxy-3- methoxybenzaldehyde, trans-4-decenal, methylnonylacetaldehyde, citral, 2,4-dimethyl-3- cyclohexen-1-carbaldehyde, and mixtures thereof.

Like in step 1 the reaction of step 2 can be conducted very simple by mixing the reactants and stirring the mixture at room temperature and ambient pressure. Again, if at least one of the educts is liquid there is no need to add a solvent. However, addition of solvent is possible, provided that the solvent does not react with any of the reactants.

Preferably, the molar amount of the amine-reactive fragrance molecule used corresponds or slightly exceeds the molar amount of secondary amine groups available in the amino-functional polymer. The molar ratio of amine-reactive fragrance molecule to secondary amine groups is preferably from 1 : 0.9 to 1 : 1.5, particularly preferred from 1 : 1 to 1 : 1.2, more particularly preferred from 1 : 1 to 1 : 1.05.

A further object of the invention is a process for the production of a pro-fragrance according to the invention, wherein

a. an amino-functional polymer comprising at least a primary amine group and at least a secondary amine group is reacted with a modifier compound comprising at least a functionality which is able to react with primary amine groups, and b. subsequently the resulting modified amino-functional polymer is reacted with an amine- reactive fragrance molecule comprising at least a ketone and/or an aldehyde functionality,

wherein the modifier compound used in step a is not an amine-reactive fragrance molecule comprising at least a ketone and/or an aldehyde functionality.

Preferred reactants and reaction conditions have already been disclosed above.

Pro-fragrance compounds of the invention show excellent characteristics. They provide an initial good perfume performance immediately after application as well as a good perfume release from the treated substrate over a prolonged period of time. Furthermore, they can be easily dissolved in aqueous systems. It is quite surprising that modification with a modifier compound results in a remarkably improved perfume performance immediately after application compared to non- modified pro-fragrances, whereas there is no deteriorating effect with regard to fragrance durability.

Hence, the pro-fragrances are very useful ingredients for any product which is expected to show superior fragrance characteristics.

A further object of the invention is therefore the use of a pro-fragrance compound according to the invention as pro-fragrance in a detergent, cleaning, fabric treatment or cosmetic composition.

Still a further object of the invention is a detergent, cleaning, fabric treatment or cosmetic composition comprising from 0.001 to 50% by weight of at least a pro-fragrance compound according to the invention.

Another object of the invention is a method of treating a substrate to impart thereto surface substantive, slow odor release perfume materials, which method comprises contacting the substrate with a composition comprising from 0.001 to 50% by weight of at least a pro-fragrance compound according to the invention.

The pro-fragrances according to the invention may be used as the single fragrance substance, but it is also possible to use mixtures of fragrance substances, which are comprised only partially of the

pro-fragrances. In particular fragrance substance mixtures containing 1 to 50 wt%, preferably 5 to 40 wt% and in particular max. 30 wt% of pro-fragrances may be used. In other embodiments in which the delayed fragrance effect of the carrier-bound form is of particular importance, advantageously at least 30 wt%, preferably at least 40 wt% and in particular at least 50 wt% of the total perfume contained in an agent is introduced into the agent via pro-fragrances according to the invention, whereas the remaining 70 wt%, preferably 60 wt% and in particular 50 wt% of the total perfume present in the agent is sprayed as usual or is otherwise introduced into the agent.

By the distribution of the total perfume content of an agent, e.g., a detergent or cleaning agent in perfume, which is present in the form of the inventive pro-fragrances and perfume that has been incorporated traditionally, a variety of product characteristics can be implemented which become possible only through the use of pro-fragrances according to the invention. For example, it is possible to divide the total perfume content of an agent into two portions x and y, whereby the portion x comprises inventive pro-fragrances and the portion y comprises traditional perfume oils.

The fragrance substances that may be incorporated into the agents in the traditional way are not subject to any restrictions. Individual perfume substance compounds of natural or synthetic origin, e.g., of the type of esters, ethers, aldehydes, ketones, alcohols and hydrocarbons may thus be used as the perfume oils and/or fragrance substances. Perfume substance compounds of the ester type include, for example, benzyl acetate, phenoxyethyl isobutyrate, p-tert-butylcyclohexyl acetate, linalyl acetate, dimethylbenzylcarbinyl acetate (DMBCA), phenylethyl acetate, benzyl acetate, ethylmethyl phenyl glycinate, allylcyclohexyl propionate, styrallyl propionate, benzyl salicylate, cyclohexylsalicylate, floramat, melusat and jasmacyclate. The ethers include, for example, benzylethyl ether and ambroxan; the aldehydes include, for example, the linear alkanals with 8 to 18 carbon atoms, citral, citronellal, citronellyl oxyacetaldehyde, cyclamenaldehyde, lilial and bourgeonal; the ketones include, for example, the ionones, α-isomethylionone and methyl cedryl ketone; the alcohols include anethole, citronellol, eugenol, geraniol, linalool, phenylethyl alcohol and terpineol; the hydrocarbons include mainly terpenes such as limonene and pinene. However, mixtures of various perfume substances which jointly produce an attractive fragrance note are preferred.

Such perfume oils may also contain mixtures of natural perfume substances such as those accessible from plant sources, e.g., pine oil, citrus oil, jasmine oil, patchouli oil, rose oil or ylang- ylang oil. Also suitable are muscatel sage oil, chamomile oil, clove oil, lemon balm oil, mint oil, cinnamon leaf oil, linden blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil and labdanum oil as well as orange blossom oil, neroli oil, orange peel oil and sandalwood oil.

Other traditional perfume substances that may be used include, for example, the essential oils such as angelica root oil, anise oil, arnica blossom oil, sweet basil oil, bay oil, champaca blossom oil, silver fir oil, fir cone oil, elemi oil, eucalyptus oil, fennel oil, spruce needle oil, galbanum oil, geranium oil, ginger grass oil, guaiac wood oil, gurjun balsam oil, helichrysum oil, ho oil, ginger oil, iris oil, cajeput oil, calamus oil, chamomile oil, camphor oil, canaga oil, cardamon oil, cassia oil, pine needle oil, copaiba balsam oil, coriander oil, spearmint oil, caraway oil, cumin oil, lavender oil, lemon grass oil, lime oil, mandarin oil, lemon balm oil, ambrette seed oil, myrrh oil, clove oil, neroli oil, niaouli oil, olibanum oil, origanum oil, palmarosa oil, patchouli oil, Peru balsam oil, petitgrain oil, pepper oil, peppermint oil, allspice oil, pine oil, rose oil, rosemary oil, sandalwood oil, celery seed oil, spike lavender oil, star anise oil, turpentine oil, thuja oil, thyme oil, verbena oil, vetiver oil, juniper berry oil, vermouth oil, wintergreen oil, ylang-ylang oil, ysop oil, cinnamon oil, cinnamon leaf oil, citronella oil, lemon oil and cypress oil as well as ambrettolide, ambroxan, α-amylcinnamaldehyde, anethole, anise aldehyde, anise alcohol, anisole, anthranilic acid methyl ester, acetophenone, benzylacetone, benzaldehyde, benzoic acid ethyl ester, benzophenone, benzyl alcohol, benzyl acetate, benzyl benzoate, benzyl formate, benzyl valerate, borneol, bornyl acetate, boisambrene forte, α-bromostyrene, n-decylaldehyde, n-dodecylaldehyde, eugenol, eugenol methyl ether, eucalyptol, farnesol, fenchone, fenchyl acetate, geranyl acetate, geranyl formate, heliotropin, heptin carboxylic acid methyl ester, heptaldehyde, hydroquinone dimethyl ester, hydroxycinnamyl aldehyde, hydroxycinnamyl alcohol, indole, iron, isoeugenol, isoeugenol methyl ether, isosafrol, jasmine, camphor, carvacrol, carbon, p-cresol methyl ether, coumarin, p- methoxyacetophenone, methyl-n-amyl ketone, methyl anthranilic acid methyl ester, p- methylacetophenone, methyl chavicol, p-methylquinoline, methyl β-naphthyl ketone, methyl n- nonylaldehyde, nonyl alcohol, n-octylaldehyde, p-oxyacetphenone, pentadecanolide, β-phenylethyl alcohol, phenylacetaldehyde-dimethylacetal, phenylacetic acid, pulegon, safrole, salicylic acid isoamyl ester, salicylic acid methyl ester, salicylic acid hexyl ester, salicylic acid cyclohexyl ester, santalol, sandelice, skatol, terpineol, thyme, thymol, troenan, γ-undelactone, vanillin, veratrum aldehyde, cinnamyl aldehyde, cinnamyl alcohol, cinnamic acid, cinnamic acid ethyl ester, cinnamic acid benzyl ester, diphenyl oxide, limonene, linalool, linayl acetate and linalyl propionate, melusat, menthol, menthone, methyl-n-heptenone, pinene, phenyl acetaldehyde, terpinyl acetate, citral, citronellal and mixtures thereof.

The pro-fragrances are preferably used in detergents and cleaning compositions, fabric treatment compositions like fabric softeners and in cosmetics. These may be solid, gel or liquid formulations, and solid formulations may be in the form of powder, granules, tablets or tabs. Liquid formulations may be solutions, emulsions or dispersions.

Detergents may be used for manual or machine washing of textiles in particular. They may be detergents or cleaning agents for industrial use or for the household area. Cleaning agents may be

used for cleaning hard surfaces, for example. They may be dishwasher detergents, for example, which are used for manual or machine cleaning of dishes. They may also be conventional industrial or household cleaners with which hard surfaces such as furniture surfaces, flagstones, ceramic tiles, wall coverings and floor coverings are cleaned. Fabric softeners include in particular fabric softeners that are used for treating textiles during or after being laundered. The cosmetics may be pastes, ointments, creams, emulsions, lotions and solutions, in particular alcohol-based solutions, which are known from fine perfumery, for example. The individual agents may be applied in any suitable form. For example, these may be agents to be applied by spraying. The inventive pro- fragrances may also be used to cover bad odors, which adhere well to solid surfaces when combined with other absorbents, for example.

Detergents, cleaning, fabric treatment or cosmetic compositions according to the invention comprise a sufficient amount of at least a pro-fragrance compound according to the invention, usually from 0,001 to 50% by weight based on the total amount of the composition.

In most cases an amount of pro-fragrance compounds of clearly below 50% by weight is sufficient. Typically, ready-to-use products comprise less than 5% by weight of at least a pro-fragrance compound, preferably less than 2% by weight, particularly preferred less than 1 % by weight. Typical ranges are from 0.05 to 0.5% by weight, preferably from 0.1 to 0.2% by weight. However, perfumes may comprise a high concentration of the pro-fragrance compound, for example up to 40% by weight.

Detergents, cleaning, fabric treatment or cosmetic compositions according to the invention may contain any further necessary or additional ingredient. Such ingredients are well known to those skilled in the art.

Detergents and cleaning agents and fabric softeners may contain other conventional ingredients of detergents and cleaning compositions and fabric softeners, such as surfactants, builder substances, bleaching agents, other fragrance substances, enzymes and other active ingredients, but also disintegration aids, so-called tablet d is integrants, to facilitate the disintegration of highly compressed tablets and tabs and to shorten the disintegration times.

Surfactants in particular are among the essential ingredients of detergents and cleaning agents and fabric softeners.

The surfactant content will be selected to be higher or lower, depending on the intended use of the inventive agents. The surfactant content of detergents is usually between 10 and 40 wt%, preferably between 12.5 and 30 wt% and in particular between 15 and 25 wt%, whereas cleaning

agents for dishwashing machines contain between 0.1 and 10 wt%, preferably between 0.5 and 7.5 wt% and in particular between 1 and 5 wt% surfactant, for example.

These surfactant substances may be selected from the group of anionic, nonionic, zwitterionic or cationic surfactants, but for economic reasons and because of their performance spectrum, anionic surfactants are definitely preferred in washing and cleaning. With respect to surfactants and emulsifiers which are preferably used according the invention it is referred to the disclosure of WO 2008/107346.

With respect to builder substances which are preferably used according to the invention it is referred to the disclosure of WO 2008/107346.

The compositions contain builders preferably in amounts, based on the composition, of 0 to 20 wt%, preferably 0.01 to 12 wt%, in particular 0.1 to 8 wt%, and most preferred 0.3 to 5 wt%.

In addition to the ingredients already listed, the inventive detergents and cleaning compositions may additionally contain one or more other substances, preferably selected from the group consisitng of bleaching agents, bleach activators, enzymes, pH adjusting agents, fluorescent agents, dyes, foam inhibitors, silicone oils, anti-redeposition agents, optical brighteners, graying inhibitors, dye transfer inhibitors, soil-release compounds, corrosion inhibitors and silver protectants. With respect to bleaching agnets, bleach activators, enzymes, pH adjusting agents, fluorescent agents, dyes, foam inhibitors, silicone oils, anti-redeposition agents, optical brighteners, graying inhibitors, dye transfer inhibitors, disintegration aids, corrosion inhibitors and silver protectants which are most preferably used and with respect to the preferred amounts of those substances it is referred to the disclosure of WO 2008/107346.

This list of ingredients of fabric softeners and detergents and cleaning agents is by no means conclusive but instead merely gives the most essential typical ingredients of such agents. In particular, inasmuch as they are liquid or gel preparations, these agents may also contain organic solvents. These are preferably monovalent or polyvalent alcohols with 1 to 4 carbon atoms. Preferred alcohols in such agents include ethanol, 1 ,2-propanediol, glycerol as well as mixtures of these alcohols. In preferred embodiments, such agents contain 2 to 12 wt% of such alcohols.

Essentially the agents may have different physical states. In another preferred embodiment, the fabric softeners, detergents or cleaning agents are liquid or gel agents, in particular liquid detergents or liquid dishwashing detergents or cleaning gels, and they may in particular also be cleaning agents in the form of gels for cleaning toilets.

These are preferably intrinsically viscous cleaning agents in the form of gels with a viscosity of 30,000-150,000 mPas, containing as the gelatinizing agent a polysaccharide, as the emulsifier and wetting-active component a C _8- io alkyl polyglycoside or Ci _2- i ₄ alkyl polyglycoside (APG) and perfume oil. Fatty alcohol ether sulfates (FAEOS) and fatty alcohol sulfates (FAS) may also be present as additional co-surfactants. The ratio of APG to co-surfactant is then usually greater than 1 , preferably between 50:1 and 1 :1 , especially preferably between 10:1 and 1.5 to 1 and most especially preferably between 5:1 and 1.8:1. In particular these are stable, shear-diluting cleaning agents in the form of a gel containing a polysaccharide, a surfactant system and perfume components, which are characterized by the fact that

• they contain a polysaccharide, preferably a xanthan gum, in amounts between 1 and 5 wt%, preferably 1 to 5 wt%, especially preferably 1.5 to 3.5 wt% and most especially preferably 1.8 to 3 wt%,

• they contain as a component of the surfactant system a C ₈ . ₂₂ alkyl polyglycoside in amounts between 3 and 25 wt%, preferably 4 and 20 wt%, especially preferably 5 and 15 wt% and most especially preferably 5 and 12 wt%, and

• they contain the perfume component(s) up to 15 wt%, preferably 2 to 12 wt%, especially preferably 3 to 8 wt%,

• and they optionally contain other ingredients such as lime-dissolving agents, dyes, microbicidal agents (e.g., isothiazoline mixtures, sodium benzoate or salicylic acid), pearlescent agents, stabilizers, cleaning enhancers and odor absorbers,

• and that the agents have a viscosity of 30,000 to 150,000 mPas, measured with a Brookfield rotary viscometer, model RVT with a Helipath device and TA spindle at 1 rpm and 23°C.

If necessary, water-soluble and water-insoluble builders may also be present in the gels according to the invention. In that case water-soluble builders are preferred because they usually have less tendency to form insoluble residues on hard surfaces. The usual builders which may be present within the scope of the invention include the low-molecular polycarboxylic acids and their salts, the homopolymeric and copolymeric polycarboxylic acids and their salts, citric acid and its salts, carbonates, phosphates and silicates. The water-insoluble builders include the zeolite which may also be used as well as the mixtures of the aforementioned builder substances. The group of citrates is especially preferred.

Other typical cleaning agents which may contain the inventive pro-fragrances include liquid or gel cleaners for hard surfaces, in particular so-called all-purpose cleaners, glass cleaners, floor and bathroom cleaners as well as special embodiments of such cleaners, which include acidic or alkaline forms of all-purpose cleaners as well as glass cleaners with a so-called anti-rain effect. These liquid cleaning agents may also be present in one or more phases. In an especially preferred embodiment, the cleaners have two different phases.

"Cleaner" in the broadest sense is a term for formulations (usually containing a surfactant) with a very wide area of application and a very different composition, depending on the application. The most important market segments are household cleaners, industrial (technical) cleaners and institutional cleaners. Depending on the pH, a distinction is made between alkaline, neutral and acidic cleaners; according to the form in which it is offered, a distinction is made between liquid and solid cleaners (also in tablet form). These so-called cleaners for hard surfaces should yield an optimal profile of use (in contrast with dishwashing agents, which are also classified in the product group of cleaners) both in a concentrated state and in dilute aqueous solution when combined with mechanical energy. Low-temperature cleaners manifest their effect without elevated temperature. Surfactants and/or alkali carriers, alternatively acids, optionally also solvents such as glycol ethers and lower alcohols are crucial for the cleaning effect. In general, the formulations also contain builders and, depending on the type of cleaner, bleaching agents, enzymes, microbicidal or disinfecting additives as well as perfume oils and dyes. Cleaners may also be formulated as microemulsions. The success of cleaning depends to a great extent on the type of dirt - which may also vary greatly geographically - and the properties of the surfaces to be cleaned.

Household cleaners may be formulated as universal cleaners or as special cleaners for ceramics, tiles, windows, plastics, (carpet) floors, cooktops, baking ovens, microwave ovens, plumbing cleaners or bathroom or toilet cleaners. Pipe cleaners are adjusted to be alkaline and consist of, for example, solid sodium hydroxide and aluminum powder which, when dissolved, release hydrogen which ensures a corresponding turbulence in the pipe segments to be cleared. In addition to containing surfactant and builder, sanitary cleaners mainly contain active ingredients to reduce the microbe count, whereby sodium hypochlorite, which was used previously, has been partially replaced by hydrogen peroxide or other peracid compounds. Toilet cleaners are mainly acidic but may sometimes also be adjusted to be alkaline, whereby in the former case, the phosphoric acid originally used and sodium bisulfate are largely replaced by organic acids, mainly citric acid. Special cleaners also include automotive cleaners, automobile windshield cleaners, wheel rim cleaners, engine cleaners and paint application equipment cleaners in the do-it-yourself field.

In addition to the components already mentioned, the compositions according to the invention may also contain other additives and aids, such as those customary in such agents. These include in particular polymers, soil-release active ingredients, solvents (e.g., ethanol, isopropanol, glycol ether), solubilizers, hydrotropes (e.g., cumenesulfonate, octyl sulfate, butyl glucoside, butyl glycol), cleaning enhancers, viscosity regulators (e.g., synthetic polymers, such as polysaccharides, polyacrylates, naturally occurring polymers and their derivatives such as xanthan gum, other polysaccharides and/or gelatins), pH regulators (e.g., citric acid, alkanolamines or NaOH), disinfectants, antistatics, preservatives, bleach systems, enzymes, dyes and opacifiers or skin protectants.

The amount of such additives is usually no more than 12 wt% in the cleaning agent. The lower limit for use depends on the type of additive and may be as low as 0.001 wt% or even less in the case of dyes. The amount of auxiliaries is preferably between 0.01 and 7 wt%, in particular 0.1 and 4 wt%.

The aforementioned compositions may also contain binders, which may be used alone or in mixture with other binders.

Cosmetic compositions according to the invention are preferably compositions for the treatment of hair and skin.

These cosmetic agents preferably contain the pro-fragrances according to the invention in amounts of 0.001 to 10 wt%, preferably from 0.01 to 5 wt%, especially preferably from 0.02 to 3 wt% and in particular in amounts of from 0.05 to 2 wt%, each based on the total cosmetic composition.

The total amount of fragrance substances in the cosmetic agents, including the pro-fragrances, is preferably between 0.01 and 5 wt%, especially preferably between 0.1 and 3 wt% and most especially preferably between 0.5 and 2 wt%, based on the total amount of the agent. Mixtures of various fragrance substances (from the various classes of fragrance substances mentioned above) which jointly produce an appealing fragrance note are preferably used. In this case, the total amount of the at least one fragrance substance is the amount of all fragrance substances in the mixture together, based on the total amount of the agent.

In a preferred embodiment, the cosmetic agents are aqueous, alcoholic or aqueous-alcoholic preparations that contain surfactant active ingredients and are suitable in particular for treatment of keratin fibers, in particular human hair, or for treatment of skin.

Said hair treatment agents include in particular agents for treatment of human head hair. The most conventional agents of this category can be divided into shampoo detergents, hair care agents, hair setting and permanent hair waving agents as well as hair dyes and depilatories. The agents that are preferred according to this invention and contain surfactant active ingredients include in particular shampoos and treatment preparations. Such a hair washing agent or shampoo consists of 10 to 20 recipe ingredients, in individual cases up to 30 recipe ingredients. These preparations are usually in liquid form to pasty form.

Cosmetics (cosmetic agents) according to the invention usually contain other ingredients that are conventional for these agents.

Preferably they contain surfactant active ingredients or detergent-active ingredients as additional ingredients. Fatty alcohol polyglycol ether sulfates (ether sulfates, alkyl ether sulfates) are preferably used here, partially in combination with other surfactants, usually anionics. In addition to the alkyl ether sulfates, preferred agents may additionally contain other surfactants such as alkyl sulfates, alkyl ether carboxylates, preferably with degrees of ethoxylation of 4 to 10, as well as surfactant protein-fatty acid condensates. Protein-abitic acid condensate should be mentioned here in particular. Sulfosuccinic acid esters, amidopropyl-betaines, amphoacetates and amphodiacetates as well as alkyl polyglycosides are surfactants that are preferably used in shampoos.

Another group of ingredients is summarized by the term auxiliary substances and is extremely varied: for example, nonionic surfactant additives such as ethoxylated sorbitan esters or protein hydrolysates increase the compatibility and/or have an irritation-reducing effect, e.g., in baby shampoo; e.g., natural oils or synthetic fatty acid esters serve as moisturizing agents to prevent excessive removal of oil in shampooing; humectants include glycerol, sorbitol, propylene glycol (see propanediols), polyethylene glycols and other polyols. To improve wet combability and to reduce electrostatic charge buildup on the hair after drying, cationic surfactants, e.g., quaternary ammonium compounds may be added to the shampoo. For a brilliant color appearance, dyes and/or pearlescent pigments may be added. To adjust the desired viscosity, thickeners of various substance classes may be used, and pH stability is achieved by buffers based on citrate, lactate or phosphate, for example. To ensure adequate stability and storage life, preservatives such as 4-hydroxybenzoic acid ester are added; oxidation-sensitive ingredients can be protected by adding antioxidants such as ascorbic acid, butylmethoxyphenol or tocopherol.

Another preferred group of ingredients includes special active ingredients for special shampoos, e.g., oils, herbal extracts, proteins, vitamins and lecithins in shampoos for hair that becomes oily rapidly, for especially dry hair, stressed or damaged hair. Active ingredients in shampoos for controlling dandruff usually have a broad growth-inhibiting effect against fungi and bacteria. The fungistatic properties of pyrithione salts in particular, have been shown to be the cause of the good antidandruff effect.

Cosmetic compositions according to the invention may be present in different preparation forms.

The most important are skin creams, skin lotions, skin oils and skin gels. The creams and lotions are based on emulsions in O/W (oil-in-water) form or VWO (water-in-oil) form. The main ingredients of the oil and/or fat or lipid phase include fatty alcohols, fatty acids, fatty acid esters, waxes, petrolatum, paraffins and other fat and oil components mainly of a natural origin. In addition to water, the aqueous phase contains moisture-regulating and moisture-preserving substances as the

main skin care active ingredients plus agents to regulate consistency and/or viscosity. Additional additives such as preservatives, antioxidants, complexing agents, perfume oils, coloring agents as well as special active ingredients are added to one of the aforementioned phases, depending on their solubility and stability properties. The choice of the emulsifier system is essential for the emulsion type and its properties. It can be selected according to the HLB system.

In addition, the skin care agents may contain other special active ingredients, e.g., milk protein products, egg yolk, lecithins, lipoids, phosphatides, cereal seed oils, vitamins, especially vitamin F and biotin, which was previously referred to as the skin vitamin (vitamin H) as well as hormone-free placenta extracts.

The invention is further illustrated by the following examples in which all parts and percentages are by weight, unless otherwise stated. These examples were included for illustrative purposes only and shall not be construed as limiting the scope of the invention.

Examples

1. Synthesis of pro-fragrances

Example 1 : BPEI/PEG/Octanal

1.0 g (0.56 mmol) of a branched polyethyleneimine (BPEI), commercially available from Wako Pure Chemical Industries, Ltd. (weight average molecular weight Mw = 1800; 1.00 gram of BPEI contains 8.6 mmol of primary amine (-NH2) and 8.2 mmol of secondary amine (-NH-)), was reacted with 3.9 g (8.7 mmol) of the poly(ethylene glycol) methyl ether acrylate of formula (Ilia)

at 25°C for 24 h to give 4.9 g of the corresponding modified BPEI having poly(ethylene glycol) segments (BPEI/PEG). The poly(ethylene glycol) methyl ether acrylate, having a number average molecular weight Mn = 454, is commercially available from Aldrich.

In a second step, the modified BPEI (4.9 g) was reacted with 1.09 g (8.4 mmol) octanal at room temperature for 1 h to yield 5.86 g of BPEI/PEG/Octanal, a pro-fragrance according to the invention.

Example 2: BPEI/Gly/Octanal

1.0 g (0.56 mmol) of a branched polyethyleneimine (BPEI), commercially available from Wako Pure Chemical Industries, Ltd. (weight average molecular weight Mw = 1800; 1.00 gram of BPEI contains 8.6 mmol of primary amine (-NH2) and 8.2 mmol of secondary amine (-NH-)), was reacted with 0.64 g (8.6 mmol) glycidol (compound of formula V) at 25°C for 24 h to give 1.64 g of the corresponding modified BPEI having hydroxyl groups (BPEI/Gly).

The modified BPEI (1.64 g) was reacted with 1.09 g (8.4 mmol) octanal at room temperature for 1 h to yield 2.72 g of BPEI/Gly/Octanal, a pro-fragrance according to the invention.

Example 3: BPEI/QA/Octanal

1.0 g (0.56 mmol) of a branched polyethyleneimine (BPEI), commercially available from Wako Pure Chemical Industries, Ltd. (weight average molecular weight Mw = 1800; 1.00 gram of BPEI contains 8.6 mmol of primary amine (-NH2) and 8.2 mmol of secondary amine (-NH-)), was reacted with 1.66 g (8.6 mmol) [2-(Acryloyloxy)ethyl]trimethylammonium chloride (a compound of formula IV wherein R ⁷ is ethylene, R ⁸ , R ⁹ and R ¹⁰ are methyl and X ^" is chloride) at 25°C for 24 h to give 2.66 g of the corresponding modified BPEI having quaternary ammonium moieties (BPEI/QA).

Thereafter, the modified BPEI (2.66 g) was reacted with 1.09 g (8.4 mmol) octanal at room temperature for 1 h to yield 3.6 g of BPEI/QA/Octanal, a pro-fragrance according to the invention.

Comparative Example 1 : BPEI/Octanal

1.0 g (0.56 mmol) of a branched polyethyleneimine (BPEI), commercially available from Wako Pure Chemical Industries, Ltd. (weight average molecular weight Mw = 1800; 1.00 gram of BPEI contains 8.6 mmol of primary amine (-NH2) and 8.2 mmol of secondary amine (-NH-)),was reacted with 1.09 g (8.4 mmol) octanal at 25°C for 1 h to yield 2.09 g of BPEI/Octanal, a pro-fragrance according to the state of the art. 2. Water solubility

The pro-fragrances according to examples 1 to 3 and comparative example 1 were mixed with water at a concentration of 1 g/l and 5 g/l, respectively. The transmittance of the mixture at a wavelength of 500 nm was determined with a UV-vis spectrometer model JASCO V570 at 25 ⁰ C, using a quartz cell of a path-length of 1.0 cm. A high transmittance indicates that the pro-fragrance is solved, whereas a transmittance of less than about 90% means that an emulsion is formed. The results are shown in table 1.

Table 1 :

The results show that the solubility of pro-fragrances according to examples 1 to 3 in water is much higher than the solubility of BPEI/Octanal.

3. Fragrance characteristics:

To evaluate the fragrance characteristics a hydrolysis test as well as a sniff test were performed.

Hydrolysis test:

The pro-fragrances were mixed at room temperature with water to yield a concentration of 5.0 g/l BPEI/PEG/Octanal, 2.0 g/l BPEI/Gly/Octanal, 3.1 g/l BPEI/QA/Octanal, and 1.6 g/l BPEI/Octanal, respectively. These concentrations correspond in each case to a molar concentration of octanal of 6.3 mmol/l. The respective aqueous solutions were overlayered with a hexane solution of dodecane, used as internal standard for quantification of the released octanal by gas chromatography. The amount of hexane solution in each case almost equaled the volume of the aqueous solution. The concentration of dodecane was 3.0 mmol/l. The octanal released due to hydrolysis transferred into the hexane layer. Over time small portions (each time less than 0.1 ml) of the hexane solution were sampled. Each sample was diluted with hexane, and then analyzed by gas chromatography, using a Shimadzu GC-2014 with a J&W Scientific DB-5 capillary column. The injector and the detector were heated at 250 ⁰ C. During the measurement, the column oven was heated from 100 ⁰ C to 22O ⁰ C at a rate of 10°C/min.

Figure 1 shows the amount of released octanal in % by weight, based on the theoretically available amount of octanal in the pro-fragrance, versus the time of hydrolysis in hours.

As can be seen from Figure 1 , the initial release rate of octanal is higher for pro-fragrances according to examples 1 to 3 compared to the state of the art pro-fragrance according to comparative example 1.

In the case of BPEI/QA/Octanal, octanal was quickly released within the first 10 hours and the total amount of octanal released during that period was about 30%. After about 10 hours the release rate decreased. However, hydrolysis went on further releasing a considerable amount of octanal. The total amount of released octanal was 41 % after about 33 hours.

BPEI/PEG/Octanal released octanal at a very high rate within the first 5 hours. The total amount of octanal released during that period was about 15%. After that the release rate decreased. The total amount of released octanal was about 17% after 7.5 hours and 20% after 33 hours, respectively.

In the case of BPEI/Gly/Octanal, the released amount of octanal was about 7% after 7.5 hours and about 18% after 30 h, respectively.

The comparative pro-fragrance BPEI/Octanal released only about 5% octanal within the first 7.5 hours and about 14% within 33 hours. This means, the release rate as well as the amount of released octanal were comparatively low.

The results show that pro-fragrances of the invention show an excellent initial perfume performance.

Sniff test:

Cotton strips were dipped in a solution of the pro-fragrance, dried and presented to an expert for evaluation of the odor grade after 1 , 3, 6, and 8 days, respectively. The odor intensity of the pro- fragrances according to examples 1 to 3 was higher or equal to the odor intensity of BPEI/Octanal indicating good fragrance durability.

This result is very surprising since the high initial hydrolysis rate of the pro-fragrances according to the invention causes a high amount of octanal being released within just one day. Hence, one would assume that this would deteriorate the long-term fragrance characteristics simply because the amount of octanal available decreases faster than in the case of the reference pro-fragrance BPEI/Octanal.