CA2249588A1 - Detergent compositions containing fragrance precursors and the fragrance precursors themselves - Google Patents

Abstract

Detergent compositions containing certain acetals or ketals which hydrolyze upon exposure of surfaces washed in solution of said compositions to a reduction in pH, thereby releasing a fragrance which is characteristic of one or more of the hydrolysis products . The acetals and ketals themselves also form part of the invention; they have a molecular weight of at least about 350; a ClogP of about 4, and a half-life of less than 60 minutes when measured at pH = 0 by the pro-fragrant hydrolysis test.

Description

WO 97/34986 PCT~US96/04060 L~ r~ COMI~ IIS CONTWNING FRAGR~NCE PRECURSORS AND l~E FRA-GR~NCE PRECURSORS TH~MSaVE~S

S

FIELD OF THE INVENTION
The present i :c relates to dch.~etl~l or ketal pro-f _nd methods for ~ ~! e the telivery of sueb orlpnie to te~tile tticles nd other surfaccs w sbed with ~it - - and in eert~
ef~- -<1 p u ~ v ~ ~ . J which are believet to be novel More I 1 ~ ly the rel_tes to l_undry d~ h ~ cc - - in which there is a delYyed reles e of 15 _ ~~ from surf~ces wsched in sn ~queous b~th in the presenee of ~ dCh.l, -inC The t~is released in L _ -- ~ form when the surfaee is in eontact with a lower pH c.. ~ such as eont et with w ter e rbon dio~ide gas bumid air or the like Bl'C~5ROUND OF THE INVENTION
Most chve eome ~o e%peet seented l-undry products and to e~pect tbat fabrics wbieh h_ve been I ~ d to ~lso bave a pleasing f~ ~ It is also desired by c ~ for d f~ries to ms nt_in tbe plessing f~ over time Perfume 9 ~_ mal~e laundry - t; ~re = ~; ly ple_sing to tbe and in some e scs the perfume imparts aple~nt i g ~ to fabrics tre ted i .i~itl Il~ _~ r the mount of perfume earry-over from n ~ueous huntry bsth onto fabrics is often marginal a~d does not last long on the fabric ID
25 - some perfume delivery systems an not stable under alk_line - sueh as in tdq det4.~ - eoml - e; - } - - are often very eostly nd their use in ~ nd i........... ~tf ~ delivery to fabrics from det~ g~ltS rcsults in a very high cost to both r ~ nd d~Industry i Cfu G to seelc with urgency for more efficient nd effective ~ ~ e e delivery in laundry products especially for in the ~G.U.i ' of ~ e fragrance to tho I Gd fabrics Acet ls and Icetals have long been Itnown in ~ ~ See Steffen Arctantct ~Perfume - nd Pl-vor t~ c Amtander N J 1969 The majority of these are methyl and ethyl types nd -le weights may range widely See for r~ ", Arctander abstr ct numbers 6 11 210 651 689 1697 1702 2480 2478 For 2478 which is ~L y ~r ~ ~de J, l " ellyl acetal e - weight 414 7 A~tander reports ~ and it is not Gaag6 - ~ to say that this ~cetal is p~ ic~ly ~ - and obsolete in today s ~ y~ For 2480 which is p~ ~ ld~l~yde digeranyl acetal Arctander reports ~ the title material does not offer W O 97/34986 PCTAU~5r'01~G0 suh~ -1 advantages or unique odor type and it may be cu..~i-le.ud of little more than ac- ' -interest today~. This latter material was still co..ll.~.c.ally available in 1992 as ROSETAL A
(Catalogue, IFF). The present i~ tOl7, have found indeed that the acetals of aldehydes which have low ~ q- weight and contain a C6Hs moiety, such as bPn~ ebyde and pL~,..yl-~e~ Phyde, do not have very desirable odor character for use in a pro-rr..~
detergent mode. Yet another group of cu~ ;al acetals sold for iucor~tlon in ~.LI..~,s are those of undecylenic aldehyde, such as the digeranyl or dicitronellyl acetals. The present h~
have fûund that these materials too are not very desirable for use in pror...~ g detergent ca ~ ~ ; 1 jnnc Carrier ",.~-t~ for perfume delivery, such as by Pnrars~lqtiQn, have been taught in the prior art. See for e~ample, U.S. 5,188,753.
Early efforts to delay release of pc.rulues in d~telg~..ts include the use of certain O~L ~ C comr: ';, such as titanate or ~ ~r~-~ esters. See U.S. Patent 3,849,326, Jaggers et al, issued Nov. 19, 1974 and U.S. Patent 3,923,700, Jaggers et al, issued Dec. 2,1975.
15 Limited amounts of titanium or Lhcu~iu u can be useful as catalysts for syr~th~-ci7ing pro-fragrant ~ lC herein, and may be present in minor amounts in co~l~,alir,on to the present i~ tiO.,;
however, ~ c titanium or ~h~ - CQ ~I~u~ . Ot the metals per se, are not essential ~nl, ' of the pro-fragrant - ;als herein.
U.S. Patent S,378,468, Suffis et al, issued lan. 3, 1995 ~u;clibes specific types of personal care c .~ ~ s, such as de~c sticks, Co~ J.i7"l.g assertedly "body-activated"
fi g -- - The term -3Pr~ - Iy refers to the previously known tendency of ~ jrlc such as acetals derived from f. " -- alcohols to hydroly_e under acidic pH cn l;~ thereby releasing r.~ -e See, for e~ample, U.S. 3,932,520, Hoffman, issued January 13,1976.
Factors affecting 5~ of rl ~ --e lc on fabrics are d;~ d in Estcher et al. JAOCS 71p.31~(1994).
The selected potential r...g. - materials described by Suffis et al include pr licular acetals and ~etals, P~ p'ifiP~ by pl.,pyl(, _ gtycol vanillin acetal. The j, ~~ e~Pn~rlifiPd Iy are rather hydrophilic short chain alcohol or diol derivatives of fi..~ e aldehydes and upon hy: ol~;.is, deliver one mole of the aldehyde per mole of the potential fi..~.~cc material.
30 The present ilJ'.. believe that hydrophilic acetal or ketal ~te.;als, i.e., those having a CLogP
value (described ~ ~rt~,.) of less than 4 have at best limited usefulness in laundry d~,t~.,~,. -c~ po7;tin~ The Suffis et ~I d~ r is designed to be inco~yol~t~d with a personal care product vehicle, resulting in clear dr~ol~-~ sticks and the like.
For d~,tu~_nt use, it is i~lL..~t that rather hydm~hcb;c pro-fragrant co-~ Ic be used 35 in order to enhance ~4pQ~ r onto surfaces in the wash solution and retention on the washed surface during rinsing. In Suffis et al, the CO~UI~.;r;nnc cont~ininp the potential fi..~j.~ce ~ 1 are applied directly to the substrate (i.e. skin); therefore, the dPpQ~itinn p..b~ -resulting from dilution, rinsing, etc. are not at issue.
More q~ifi~ally, in contrast to deodorant sticks and the like, laundry det~ ..t~ are used in dilute aqueous form and contain uu.uc.ous detergent adjuncts such as synthetic d~t~ b~
S builders, enzymes and the like which are capable of - ~1i7ing, or solubiliing the pro-fia~.~ce.
Further, in order to remove detergent adjuncts and the soils displaced by detergent adjuncts from the fabrics, the latter are rinsed after washing. The rinsing tends to remove ~h. useful pro-fl"~ c material (lepnc~ d Thus both the det~.~eut adjuncts and the essential steps of the wash process itself all work against the effective delivery of pro-f~ - to the fabrics bein~ washed.
10 Moreover, high-efficiency pro-fragrant systems are desired for laundry purposes. In many laundry ~ppli~_l jn~c, the use of heated tumble-drying ~ rli -'S further e~aceil the problem of delivering adequate residual f...~ ce to te~tile fabric surfaces. Suffis et al are silent on both the nature of these severe technical problems and ~ho.lco. ;~g.- as well ac methods and specific pro-f,a~ ~ to overcome them.
It has now .. ~"i .m~l~ been discovered that these p,ohl- can , . ~ Iy be overcome by the selection of specific organic pro-fragrance types. Moreover, when these pro-f~ .~c~ types are selected, a simple but effective method is ~- ccf--r. lly provided for their effective delivery. Acco~dmgly, objects of the present invention include the p,u.;~;on of such pro-fm& -~ types and the C~~ r ~'- " ,, d~,t~,.B t CQ~ ti-~nc and methods. While the present 20 invention is primarily directed to the laundering of fabrics, the co~ ionC of the present invention are also useful in the washing of other surfaces (e.g. hard surfaces such as floors, walls, and dishes) when it is desired to impart residual f,~.g - - to the washed surface.
By the term ~pro-f. ~ " herein, it is meant a .-, ~ which may or may not be odor.f~.uus in itself but which, upon hydrolysis, produces a desirable odor which is cha.~t~ lic 25 of ODO or more of its h~d.ol~;.is products. Of course, mi~tures of pro-f~ e c- ~ ' can abo be J ~,dapro-f~
SUMMARY OF THE INVENTION
The present invention relates to a detergent cnmrcitinn for iu-~ lif~g residual fragrance to surfaces washed with aqueous solutions of said d~te.~ t, said det.,.geJt co- ~ g.
(a) a pro-fragrant cn ~ d selected from the group ~ - g of acetals, ketals, and mi~tures thereof, wherein at least one of the parent aldehydes, ketones, or alcohols of said pro-fragrant acetal or ketal is a fi..~ nce co..~ . said pro-fragrant , c ~ having;
(i) a '- 1~ weight of at least about 35û, (ii) a CLogP of at least about 4, preferably about 6 or higher, more preferably about 10 or higher, wherein CLogP is the logarithm to base 10 CA 02249588 l998-09-2l W O 97/34986 PCT~US9~10G0 of the octanol/water partition coefficient of said pro-fragrant c~-r-and (iii) a half-life of less than 60 minutes, when measured at pH 0 by the Pro-Fragrant Hydrolysis Test; and (b) adetersive surf h wherein said det.,rO_~t co ~ has a pH of at least 7.1, generally in the range 7.1 to 13, more typically in the range from about 7.5 to about 12, as inAic ~ ~ in detail h~ h.after.
The present invention also relates to a method of delivering residual f...O.~ces to a washed surface.
All pe. ~ ge5, ratios, and proportions herein are on a weight basis unless otherwise All doc~ cited are hereby .ncc,.~ .t~,d by ~er~.~"c;.
DETAILED DESCRIPTION OF THE INVENTION
Pro-r~
The pro-f..~O. ~ ~ ~ of this i.,.rention are acetals, ketals, or mi~tures thereof, provided that 15 _ , ' from which they are formed cou-~,.ise at least one f...O . e .,- . _ ~ Acetals and ketals may in general be considered as derivable from aldehydes or ketones in c~ with alcohols. These aldehydes, ketones and alcohols are herein termed "parents~ or ~parent comr '-~ of the acetal or ketal. At least one parent of any of the instant acetals or ketals is a r O -~e , ~ AAAirjo--~ any pro-f..~ f c~ c A of the ..,~re,.ti~e -mr-- ~i - has 20 the following p.u?e.~
(i) I - le 1~ weight of at least about 350, (ii) CLogP of at least about 4, (preferably at least 6, more ~ ,f~,.~ly at least 10) wherein CLogP is the logarithm to base 10 of the octanol/water partition cc.~rfi~ of said pro-fragrant ~ 1 and (iii) a half-life of less than 60 minutes, when - ~d at pH 0 by the Pro-Fragrant Hydrolysis Test.
These pro-f.~, c , ' are stable under pH crnAiti~ - e -: ~,d in the f~ ' ~ and storage of det.,.~,_nt products which have a pH of from about 7.1 to 13, and during ' t use of such products. Due to their high -lo _' weight and h~J~I r~ ' ' Y~
30 these pro-r...O ~ give .~s -bly good deFo~i~inn from a laundering solution onto fabrics. Because the pro-fragrant comr ' are subject to hydrolysis when the pH is reduced, they hydrolyze to release their cr ~ J~ f.~O. ~e co..~l~u ~c when the fabrics upon which they have been d~ '~ are e~posed even to reduced pH such as present in rinse water, air and humidity. The reduction in pH should be at least 0.1, preferably at least about 0.5 units.
P~ef.,,al,~ the pH is reduced by at least 0.5 units to a pH of 7.5 or less, more preferably 6.9 or less. Plcf~ ~Iy, the solution in which the fabric (or other surface) is washed is aLkaline.

CA 02249588 l998-09-2l W O 97/34986 PCT~US9~'n10G0 An ilU~JO.~dut class of preferred acetals herein are those derived from parent aldehydes other than those which possess both of the following characteristics: (a) low rnole ' weight and (b) contain a C6Hs moiety which has no suhs~ih~Pnt groups other than the aldehyde itself. Such relatively ~nd ~ acetals for the present purposes are those derived from bPn7q~dPhyde and S p~ yl~ P~yde. More preferably, acetals herein, when they comprise an aromatic moiety, will be derived from a parent aldehyde having ~r~e tq~ weight above about 125, more preferably above about 140.
Another i upo,~t class of p.e~ ,d acetals herein are are those derived from a fragrant Cg- or higher ~ _t _ a~ ~ aldehyde and a fragrant or non-fragrant alcohol particularly the C6-C20 10 (preferably Cll-C20, more preferably C14-CIg) s hurated or u.~lul.~ted, linear or branched aliphatic alcohols, c- ~ 'y referred to as deh~g-nt alcohols. Optionally said alcohols can be alkoAylated with I to 30 moles of ethylene oAide propylene oxide or miAhures thereof. Preferred alcohols in the above group are illustrated by OXO alcohols and Guerbet alcohols. Aromatic or aliphatic alcohols can be used.
Alternately, though less desirably, other hyd,u~lhob.c non-fragrant alcohols may be C~hcfi~t~d for the above-i~ fiPA alcohols while ~--.D;n;ng within the spirit and scope of the .
More generally, a wide range of acetals and ketals are included within the invention. As noted above, the acetals and ketals are derived from an aldehyde or ketone and an alcohol, at least 20 one of which is a f,..6, e cs lF ~ Many fragrant aldehydes, ketones, and alcohols which are suitable parent c~ for the present acetals and ketals are known to the art. See, for eAarnple, Arctander's c- ~ f~ uced hc.Gmdbu~e for fragrant parent . ' Specific fragrant parent ~ 1 h~des include but are not limited by the following byJ,~t,upaldehyde, p-t-bucinal, FloralozoneT~, cyclarnal, triplal, helional, I;_A,~
25 aldehyde, vanillin, citral, c.l.l -llal, d~de: -1, decanal, bydro~ycitronellal, and octanal.
, the sldehyde can be non-fragrant. Nonf,~ aldehydes include 1,4 te.c~Jk~halyl d;c~l~ IPhyde or other aldehydes having low volatility by virtue of ~olre of bulky polar ti~-Specific parent alcohols of fragrant types suitable herein are likewise given in Arctander30 and include but are not limited by phenylethyl alcohol, geraniol, nerol, citron ellol, linalool, tetrahydrolinal~l, diby~Luu~y~nol, dimethylcarbitol, 9~ecen-1-ol, phenylpropyl alcohol, - phc.~ylh_Aylalcohol (~hPn~ cl or 3-methyl-5-phenyl pentanol), c- nl, pa'chonç. and 2-(5,6,6-t"h.~,tllyl-2-norbornyl) cy~ 1 Other parent alcohols which can be used include ethanol, p.~ r -I butanol, lauryl alcohol, myristyl alcohol, and 2-ethylheAanol; parent alcohols 35 having very low odor or alcohols which are PccPn-ially non-fragrant, include stearyl and behenyl alcohols. As noted supra, a preferred group of alcohols includes the d~t~ , alcohols and their alkoAylate!s.

CA 02249588 l998-09-2l W O 97/34986 PCTAUS9~10G0 Ketones herein may likewise vary in wide ranges. Suitable fragrant ketone parent' for the instant acetals and ketals include benzylacetone, methyl dihyd,u;
methyl amyl ketone, methyl nonyl ketone, carvone, geranylacetone, alpha-ionone, beta-ionone, ga ~ yl ionone, Ag~ ,cisjr ~ ~~ methyl-beta n~utllyl ketone. Other suitable 5 ketonesinclude rliL-~ s, e.g. 2,4-p~t ~lin....
Many other suitable parent alrQhnli, aldehydes and ketones are o~ COu~ ,.uially from perfume houses such as IFF, Firmenich, Takasago, H&R, Givaudan-Roure, Dragoco, Aldrich, Quest, and others.
Acetals suitable in the present invention have the following S~ UIG.

R1~:-X

Such acetals can be used to deliver r.. ~.~ce aldehydes, f.~ alcohols, or both. Rl and the H are derived from a starting aldehyde. The parent aldehyde is a fragrant aldehyde when 15 no alcohol parent is fragrant, or can be a fragrant or non-fragrant aldehyde when a fragrant alcohol has 'oeen ~~ into the acetal structure. Preferred acetals include those in which R1 ~ ;~s a C8 or larger aUcyl or alkenyl moiety. In addition, the non-fragrant aldehyde can contain one or rnore aldehyde fu_ li- ~I groups for de.i~ n, in which case the acetal can be either - ;c or polymeric. Although polymeric ~ln~ 5 are operable, p. fe.le~d acetals 20 herein are mono-acetals and di ~ '~ most preferably ~-c ~ '- The present ~
can optionally include .~r -- - ' but .' _- ~ Ic are by ~4~F- not acetals herein and can not ue used as the essential pro-fragrant ~
In general, both fragrant and non-fragrant aldehydes iU~Ol~ into the instant acetals clm be rlipr' ~, allylic or benzylic. The aldehydes can be saturated, ~ d. Iinear, 25 ~ d, or cyclic. Tbe st~lululGi. can include alkyl, alkenyl, or aryl - 1-, as well as r~lditj~ -' fu~ ti~n l groups such as ~ nholc, amines, arnides, esters, or ethers.
X and Y in the above general structure re~,.~..t ~d "~ ' n~ly variable alko~y moieties derived from alcohols that can be either fragrant alcohols or non-fragrant alcohols, provided that when no fragrant aldehyde is incm~a~ ~ ~ into the acetal, at least one fragrant alcohol is 30 i"~o,~ ~ d X and Y can be the same or different allowing the delivery of more than one type of fragrant alcohol. When the alcohols are non-fragrant alcohols, it is plef_.lud tbat they are C6-C20 hnlc, especially &tty ~ ' which may optionally be modified by etho~ylation, plU~JA,yla.tiUn or ~ ~'- X and Y can ue simple alcohols c~ p a single OH group, or can be polyols ~ g 2 or more OH groups, more preferably, diols. Preferred polyols useful 35 as parent alcohols for making acetals or ketals herein which are especially useful in heavy-duty W O 97/34986 PCT~US96/04060 laundry granules include those which are not able to form S or 6 ~ I,_r~,d cyclic acetals or ketals, such as 1,4-dimethylolcyclnhP~r ~ or I,12-dihydroxyAode The acetals herein, when formed using polyols, can he cyclic or acyclic acetals d~ g one or more aldehydes. ln general, alcohols can be saturated, I ' d, linear or S br-s-~hfA alkyl, alkenyl, alkylaryl, alkylalko~ylate derivatives with one or more alcohol groups.
The alcohols may contain s ~Aiticmsl fi~nctinn~lity such as a nines, amides, ethers, or esters as a part of their structure.
In ~re detail, the acetals herein derived from polyols can be cyclic or acyclic, . nd may contain one or more acetal groups through derivatizing one or more aldehydes. The terms cyclic 10 . nd acyclic in this conte~t refer to the presence or absence of a covalent bond ~ -: g moieties X and Y of the acetal. In cyclic acetals, X and Y as shown in general structure (I) below are typically c~ t d to form a ring co~",.~...g 2 or more carbons (n > 2). Certain cyclic acetals can be c~ f~t~ by two carbons to form a five me~t~.~,d Aio~0l9~9 ring, as shown in (II), or three carbons can be CO f~t~Ji, to form a si~ d dio~ane ring, as shown in (III); larger cyclic acetals are also known.

H
R Y R~O R O ,~

j"- ~I;
m The laundry ~ - of the present invention ~n-~ . many acetals termed ~acyclic~ because moieties X and Y are not covalently bonded to form an acetal of ring-type. Such 20 acyclic acetals may in general ~ t.f l~ contain one or more cyclic moieties in any of R, X and Y. Many pro-fragrant acetals especially preferred for liquid detergent cc ~pQ~;Iion~ herein are acyclic. For heavy duty liquid laundry (HDL) d~,te.~,_nt co ~ itio ~, a p,ef~ ,d class of pro-fragrant acetals are the acyclic dialkyl acetals derived from fragrant aldehydes that are aliphatic in structure. These acetals e~ibit i~.~ d stability in conventional HDL fo. I
For heavy-duty granular dete.~ t (HDG) cs_r-- t; s, a p.~f~,.. ~l class of acetals is the acyclic dialkyl acetals derived from r...g. -~ aldehydes. Such acetals that are allylic or benzylic in structure are more p.ef.,..~,d. Tbese materials more readily hydrolyze delivering bigger odor benefits at lower levels.
Specific p~efe~;d pro-fragrant acetal co ~ Ac are nnnlimi~irlgly illustrated by the 30 following: digeranyl citral acetal; di(dodecyl) citral acetal; digeranyl vanillin acetal; didecyl he~yl ~- - ~'d~hyde acetal; didecyl ethyl citral acetal; di(dodecyl) ethyl citral; didecyl P ~i~ol~ebyde acetal; di(phenylethyl) etbyl vanillin acetal; digeranyl p-t-bucinal acetal; didecyl triplal acetal;
di(dodecyl) triplal acetal; digeranyl decanal acetal; di(dodecyl) decanal acetal; di~ ,ncllyl laural W O 97/34986 PCT~US96.'~1060 acetal; di(tetradecyl) laural acetal; di(octadecyl) helional acetal; di(phenylethyl) . ~ el?DI acetal;
di(3-methyl-5-phenyl pentanol) citronellal acetal; di(pheny?hexyl) isocitral acehl; di(phenylethyl) floralozone acetal; di(2-ethylhe~yl) octanal acetal; di (9-decenyl)p-t-bucinal acetal; di(cis-3-he~enyl) methyl nonyl q" e~DlrlPhyde acetal and di(phenylethyl) p-t bucinal acetal.
Other pro-fragrant acetals included in preferred embodiments of the present invention are:

o,(CH2)11 CH3 ~--0--(CH2)1 1CH3 y~ ~~

~~~ ~~~t~u CH2CH3 (cH2)3cH3 The above pro-fragrant acetals illustrate ~co~yo~tion of structural features such as sio" of fatty (i.e., d~h~ ') alcohols and fatty alcohol etho~ylates into the pro-fragrant 15 acetal; ~s well as the fu~ -- of pro-fragrant mi~ed aceta?,s.
Moreover other desirable acetals herein include: acetal of p-t-bucinal and ISOFOL or other b ' ~ d d~,t-,.g~ l alcohols (Condea); acetal of triplal and two moles of CH3(CH2)110C(O)CH20H; acetal of floral~ n~ and two moles of Neodol 1-3 d~t~ alcohol ~D'L' ' ~ from Shell; diacetal of ethylvanillin and } ~ ~lL~Iul; acetal of lauryl aldehyde and 20 two moles of 2-ethyl'r - h ~ IAi~ic.nqlly, suitable acetals herein are cyclic acetals derived from the reaction of fi~.~ -- aldehydes with poylhydro~ h-co~ ne the pol~ .i.o.~ ~a~ Typical ~ .1 of suitable pol~L~dlu~ amides include the C12-Clg N-methylg' ' ~ See WO
9,2û6,154. Other sugar-derived acetal or ketal parent cc,u.~,ul-lds herein include the N-a~ko~ly 25 pol~rL~d-o~ fatty acid amides, such as Clo-C18 N-(3-metho~ypropyl) r.l More generally, suitable ketals herein can be cousl-ucled using structural prmc.~ F.
analogo~ls to those used in diC~ eCing acetals suDra. More particularly, suitable ketals have the following ~ e;

R2~!:--X
Y
Ketals can be used to deliver fragrance ketones, fragrance alcohols, or both. R2 and R3 are derived from the parent ketone, and can be the same or different, and X and Y are derived from alcohols. Provided that at least one fragrant ketone is mco.l,o. I' ~ into the ketal, the alcohols S m~ci-yor ' need not be fragrant; ~iy~lly~ when at least one fragrant alcohol is inco~. d, the ketones may be non-fragrant. In the case of inco.yGl t;-: of non-fragrant ketone, it is ylef~lod that in sum, R2 + R3 contain eight or more carbons. In addition, the non-fragrant ketone can contain one or more ketone fi~nrtinnql groups and such groups can be further derivatized so that the ketal is polymeric. While polyketals are included herein, they are less 10 p.~ife,,d than mono- and di-ketals. Monol~P~qlc are most preferred.
F-Pmplq~y diketals are shown below:

R'O~O<OR R~RoR

where R'O is derived from a perfume alcohol In general, both fragrant and non-fragrant ketones can be ~liph ~ir, allylic or benzylic.
The ketones can be sdtu. ~- ~ , ated, linear, branched, or cyclic. R2 and R3 can include alkyl, alkenyl, or aryl moieties as well as other î -~ l groups inrh~rling amides, amines, ethers, or esters.
As noted in def~ning the acetals supra, X and Y for ketals are alko~y groups derived from alcohols that can be either fragrant alcohols or non-fragrant alcohols. X and Y can be the same or different, allowing the delivery of rnore than one type of fragrant alcohol. As in the case of acetals defined supra, suitable parent alcohols for ketals include C6-C20 (preferably Cll-C20~ alcohols such as fatty alcohols and their etho~ylated, propo~ylated and buto~ylateld derivatives. It is y.-f .~d in the present ketals to u~cGlyv~dte alcohols that are fatty alcohols. Suitable ketals derived from polyols can be cyclic or acylic ketals, derivatizing one or more ketones. In general, alcohols can be ~ d, linear or branched, alkyl, alkenyl, alkylaryl, alkylako~ylate derivatives with one or more alcohol groups. The alcohols may contain ~ tic!n~l fimrtic ~ y such as amines, amides, ethers, or esters as a part of their structure. X and Y can be simple alcohols ~ - g a single OH group or polyols cnn~ining 2 or more OH groups.
Specific y~,f~l~ pro-fragrant ketal c ~ lc are rnnlimitingly illustrated by the following: di(phenyl ethyl) alpha ionone ketal; di(dodecyl) alpha ionone ketal; di (phenyl he~yl) beta ionone ketal; di (citronellyl) gamma methyl ionone ketal; di(tetradecyl) gamma methyl ionone ketal; didecyl methyl betu naphthyl ketal; .li~ cyl cis jasmone ketal; digeranyl ~

ketal; di(cis-3-he%enyl) methyl dihyd.oj~ te ketal; di(dodecyl) methyl dihyd.uJY_~ -ketal; didecyl benzyl acetone ketal; di(2-ethylhexyl) methyl amyl ketal; di(dodecyloxyethyl) methyl amyl ketal; di~octadecyl) carvone ketal; and digeranyl geranyl acetone ketal.
For heavy duty granular dete.~,_..l co,~,l,osilions or heavy duty liquid dcterb_nt~, the S l,,~fe,-.d ketals include cyclic and acyclic aliphatic ketals. More preferred are acyclic aliphatic ketals.
Other specific ketals useful herein include:

~N,(c1~2)5c~b ~~~ (CH2)5CH3 is derived from methyl dihyd.~ and a dialkylamino,.. ,.r --' -1 of the ' ~' chain-length.

~0 (cH2)1ocrl3 ~>~~

is a ketal of beta-ionone and a glyceryl fatty "~n~,st~ ~ having the " Je ~ cl~sinl~ngth.
Variations ûf the present invention include laundry deterg~ which hlcol~l acetals or lcetals wherein the parent alcohol is a polymer such as polyvinyl alcohol, starch or synthetic c~ c<;~ ath~g tri or polyhydric alcohols as - ~.
The essential pro-f~a~5,~ce; co- .po~ herein can be used at widely ranging levels. Tbus, a pro-fragrent acetal, Icetal or miAture thereof is formulated in the present det.,.gent . u~
at levels in tbe general range about 0.0001% to about 10%, more preferably from about 0.001% to S %, ~re p..;f~ ''y still, from about 0.01% to about 1%.
A pro-fi..~; ~e can be used as the sole fragrance co ~I,on~ of the present d_t~ ul 25 ~ nc, or in cc 1.~ - with other pro-fi..~,~ces and/or in co~ n with other fi~ r~ ~ ~ eA~ùde~ fiAatives, diluents and the like. For eAample, i~._o~ ali{~n of the pro-fragrant material into a wa~y ~ e such as a fatty triglyceride may further improve storage stability of the present pro-fragrant co---l~ c in granular laundry d~ t~ ..t~, especially those e-, ;~.ag bleach. In liquid or gel forms of detergent co,llpositions, hyd,ù~Jh"b:e liquid 30 e;,.t~,ud~, diluents or fi~atives can be used to forrn an em~ n wherein the pro-frsgrant ~ ~ , ' is further L li7P~ by ~ g it from the aqueous phase. Nonli~;ting P~- ' of such ~ li g rnaterials include dipropylene glycol, diethyl p' ' ' ~t and acetyl triethyl citrate.
Just as there e~cist hyd,.r'.-b;~ po.ru~.y ingfed.~ ts which can be used to stabili_e the pro-fragrant material, there also e~cist dete.ge.lcy ~..g.~die.lb which also have a perfume stabilizing effect and can be formulated with the pro-fragrant material. Such ingredients include fatty acid amines, low foaming wa~y Donionic materials ~c - 'y used in ~l~to - d;DL~aDLillgdct.,.~ b, and the lilce. In general where pro-fi,.~,~ces are used along with other fl~E
~ l in d~t~ ~ cc y~c;~ nc herein it is p~f~ cd that the pro-fragrance be added from the other r. " - e ~ ~'~
Synthesis of Pro-rl~
Acetals and ketals can be prepared by the acid catalyzed reaction of an aldehyde or ketone with an alcohol (or diol), using conventional acid catalysis such as HCI or p tQl ~r ~ acid, or Du~rt~l sulfonic acid catalysts e.g., AMBERLYST 15 . See l~le~l~Pn~, F., Synthesis, (7) 501 (1981) and Ml' s, F., Jannsen Chim Acta (1) 10 (1983). Many aldehyde, ketone and alcohols useful in the synthesis of acetal and ketal pro-fiaE.~ces of the present iu~ iOI are sensitive to strong acid c--' - ~ and can undergo L ' ' ' I'' side reactions. See Bunton, C.A.
et al, J. Org. Chem. (44), 3238, (1978), and Cort, O., et al, J. Org. Chem. (51), 1310 (1986). It is also known that acetals of alpha, be a I ~ _~ i aldehydes can undergo ~, t; - of the double bond under the ~p~ up. sel~tir of the acid catalyst. See Me' PnS~ F., Synthesis, (7), 501, (1981) and Lu, T.-J, et al. J. Org. Chem. (60), 2931, (1995). For acid sensitive rn~ ~Prials, acid catalysts with pKa's between 3 and 4 are the most desirable to ~i~P double bond _ ~ ~I while ~ the reactivity necessary to produce the acetal (or ketal). For e~ample, in the s.~ ' - of d ~ yl decanal, p-tnl - lf - acid (pKa = 1) causes ~ ud~i. ' '~
side reactions with geramol. Citric acid (pKal =3.1, pKa2 =4.8, pKa3 =6.4) can be used to form 25 the acetal without side . ~ ~ ti Another l~ ' , ~ of avoiding side reactions in pl~Jaling acetals and ketals of acid sensitive ~ l;, such as geraniol, is by t. ~ l ~ of a dimethyl acetal or ketal with a higher -le ' weight alcohol, using a mild Lewis acid such as titanium isol)f~po~flde or boron trifluoride etherate as the c. talyst.
30 Novel Pro-f(a-. -e C~L _ ' The present i ._..tiou also includes novel pro-flag~ -E C~ '--l' These can be broadly d~ribed as being selected from the group cnnCicrine of pro-fragrant acetals, and ketals wherein at least one of the parent aldehydes, ketones, or alcohols of said pro-fragrant acetal or ketal is a r.~ -e ~- . 1, said pro-fragrant ~- . 1 having:
(i) a ~ ul- - weight of at least about 350, W O 97/34986 PCT~US96/OlOGO

(ii) a CLogP of at least about 4 (preferably at least about 6, most preferably at least about 10), wherein CLogP is tbe logaritkm to base 10 of the Octanol/Water Partition Coefficient of said pro-fragrant con.l.ou.ld, and (iii) a half-life of less than 60 minutes, when measured at pH 0 by the Pro-Fragrant Hydrolysis Test;
provided that said parent aldehyde, ketone or alcohol of said acetal or ketal COIIIIJIiS~ at least one co y~- -A selected from the group cnncicting of a) aldehydes, ketones and alcohols c~ ; .;n~ at least one aromatic moiety selected from the group cc-~ c~ g of C6H4 and C6H3 and wherein said parent aldehyde or ketone has a mo'e _'9~ weight of at least 125, preferably at least 140;
b) r~nnnsl~nholc selected from Cl l-C20 ~t~ ~ ', u ~lh.~ted, aromatic or _J . I ., linear and branch chain alcohols and aLko.~ ' of said alcohols c ~ 1~ from I to about 30 alkoxy groups wherein the alko~y groups are selected from etho~y, propoxy butoxy and mi~tures thereof;
c) pol~rL~hu~ alcohols, and d) mi~tures thereof.

F- .'- of parent aldehydes for these novel co ~l~ . l- are:
He~yl rinnsmsltlPhyde~ p t L 1, F-loralozone, cymal, pk_..yll,~ F ~1, sni~qlA~yde, vanillin, ethyl vanillin, citral, ethyl citral, citronellal, hydro~ycitronellal, methyl octyl a~e- '~P~yde, methyl nonyl sJr~'sld~hyde, octanal, decanal, lauric aldehyde, ck. ~ ' ~1, Triplal, helional, ocil.,l melonal, trwu-4-decenal, ado~al, i.so-he~enyl cyclohe~enyl carbosr'~ I ~de.
F-~ n, ' of parent ketones for these novel ---r- ~''~ are:
benzyl acetone, alpha-ionone, beta-ionone, g n ~thyl ionone, irone alpha, methyldih~dro; ~ ~, cis, e, methyl amyl ketone, methyl heptyl ketone, methyl he~yl ketone, methyl nonyl ketone, carvone, ~'- ~ ~ -, alpha~- ~ ~ e ~ ~, methyl beta , ' ~I ketone, e, ~ e F . '-- of monohydric alcohols for these novel CG ~pU~I rl5 are:
He~anol, 2-ethyl he~anol, octanol, decanol, doder -~ol, oc~ '~ ~1, phenyl ethanol, phenyl he~anol, 9-decenol, isolauryl alcohol, oleyl alcohol, 2-methyl 1 ~e ~1, decanol with 3 moles p.o~,~' - o~cide and 3 moles ethylene o~ide, dod~~.nl with 4 moles butylene o~ide and 5 moles ethylene o~ide, _ ' -I with 2 moles of p..Jpyl~ne o~ide, N,N-dihe~yl ~ r-~ 1, N,N-A~ nnql ~- , le~ include the use of monohydric alcohols such as those e~emrlifi~od by 35 Cellosolve(TM) Carbito(TM), Propasol(TU) (Union Carbide), and Neodol(TM) linear allcyl alko1~ylates (Shell), Tergitol TMN(TM) and 15-S(tM) branched alkyl etho~ylates (Union Carbide), and Plurafac( tM) modified alkyl etho~ylates (BASF).

PCTtUS96/04060 W 0 97/349~6 F - . l of polyhydric alcohols are glycerol, mannitol, sorbitol and glucose, as well as s ~h~ d polybydric alcohols such as glycerol laurate, glycerol mrnnol~ ~e~ sorbitan laurate, sorbitan oleate" sucrose dioleate, N~dodecyl ~ o~ -...;nP and dodecyl glucose. Additional l, ' include Clo-C18 N-alkyl polybydroAy fatty acid amides. See WO 9,206,154.

Test Methods C'~lrl~l on of CLo~P
The pro-f a~ ~c of the invention are cl~a,aete~izcd by their octanol/water partition coeffiri~n~ P. The octanol/water partition co~ffiriPn~ of a pro-r~ .ce is the ratio between its 10 equilibrium .cnc ~ ~tion in octanol and in water. Since the partition co~rr~c;~.lt~ of the pro-f~ nre CC,~ o .. ~c are large, they are more cooveniently given in the form of their IGO ill~ to the base 10, logP.
The logP of many ~~~-r ~ have been reported; for eAample, the Pl 72 ~
available from Daylight ~ Inru-~tion Systems, Inc. (Daylight CIS), contains many, along IS with citations to the original literature.
However, the logP values are most conveniently c~lrul- 3d by the ~CLOGP~ program, also available from Daylight CIS. This program also lists CA~ ~ I logP values when they are available in the Pomona92 database. The ~c~lrlll-t~d logP~ (CLogP) is ~ by the fragment ~ . pe~ ~ICI of Hansch and Leo (cf., A. Leo, in Coln~,. h- ve Medicinal l~k- y, Vol.
4, C. Hansch, P.G. $- s, J.B. Taylor and C.A. Ramsden, Eds., p. 295, Pe.l ~ Press, 1990). The fragme~t approach is based on tbe chemical structure of a COI~ L~U~ ~I and takes into account the numbers and type of atoms, the atom connectivity, and chemical bonding. The CLogP
values, which are the most reliable and widely used ~ ~:5 for this pL~-:co~ ' property, can be used instead of the CA~e~F ~ I logP values in the selection of pro-fra_ - Determination of Hydrolysis Half-life (t-1/2) Hydrolysis half-life is the ~ t used to det~ int the ease with which the pro-li V -e ~ . ~ u ~~ ~s acid hydrolysis and thereby releases its f O c-, ~l..,...--l(s) UpOD eAposure to acid con~ ne The pro-fragrant cc , _ ~e of the iL~V~,..tio~ have a half-life of less than 60 minutes, under the described hydrolysis conAi~iol~c at pH 0. Preferably, pro-30 r.~O - of the i.lv.,.llion have a half-life at pH 2 of less than 60 minutes. For granular d~te.O ~ the more reactive pro-f,..gl~c~c, that is, those with half-life at pH 2 of less than one minute, are most suitable, although those having a half-life of less than 60 minutes at pH 0 are also useful. For liquid d~,t~.o- a~ ~l ~ c~ pro-f ..O. -~f having a half-life of less than 60 minutes at pH 0, and half-life greater than one minute at pH 2 should preferably be used.
Hydrolysis half-life is det~.~un~ by UVtVis ~ ,u~Opy in a 90tlO dioAane/water system at 30~C by following the ~r of the carbonyl ~' ' -e Because of the hydl~p'-~: ity of the pro-f~aOI~ce co ~ i.A~; of the invention, a high dioAane/water ratio is W O 97/34986 PCT~US9~ 60 needed to ensure solubility of the pro-r~ u~c. The pH of the water used is achieved by using aqueous HCI. The cnn~ ti on of the pro-f.~l. u~~ in the dioxane/water system can be adjusted toachievee ~_.I.ent~lll~ul ~'-ahso,; --echanges.
All ue~...~ are carried out using a Hewlett Packard 8452 A Diode Array S Spe~trol '- ntometer ucing quartz l cm path length cuvette cells. Materials used include 1 ,4-dio~ane HPLC Grade 99.9% (Sigma-Aldrich), lN HCl volumetric solution (J.T. Baker), deioni~d water filtered with MilliQPlus (Millipore) at resistivity of 18.2 M Ohm cm. The pH's are ~un,d using an Orion 230 A -'--' .I;z.,d with pH 4 and pH 7 buffers. The lN HCI standard is used directly for pH 0 cQn~l;ti~nC For pH 2 cnn~ onc lN HCI is diluted with ~lej~mi7Ad water.
Pro-fi.. ~l -e is weighed out in a 10.00 ml volumetric flask using an analytical balance (Mettler AE 200) Precision is lll0 mg. The weighed material is dissolved in about 8 ml dio~ane Both the dio~ane solution of pro-fragrance and aqueous acid solution prepared as de~r.l~d supra are pre-heated in their separate c~.c~ to a t,~ ~p. .,~ - c of 30 + 0.25 ~C by means of a water-bath. 1.000 ml of aqueous acid solution is added to the pro-r~e.~ e solution by means of an 15 Fpprn~orf pipetter. This is followed by diluting to the 10.00 ml mark with dio~ane. Hydrolysis time is measured, starting upon addition of the acid. The pro-rR,, -e solution is mi~ed for 30 seconds by shaking, and the solution is l~-~.afc.~ed to a quartz cuvette. The a' , l ~e of the pro-f --6-- ~e solution (At) is followed at a regular series of time I' ~r ', and the cuvette is kept in the water-bath at the, ~ ~e ' - ~ -t~..~atule between . ~ Initial ~s~tl -e (Ao) 20 -- c ~ are carried out using an equal conce..tla~ion of pro-fragrance in a 90/10 v/v dio~ane deinni7Pd water solution, and final al ~ - e (Af) ~ re..l~.,t~ are taken using the hydrolyzed pro-f. ~ -e solution after the hydrolysis is .- , ' I The w~clength at which the hydrolysis is followed is chosen at the wavelength of the al,~l; -- m-'~in"~lt of the parent aldehyde or ketone Reaction half-lifes are d- -~ using conventional pr~c~lu.~s. The observed first-order rate constant (kobS) is d.,te.. ned by slope of the line provided by plotting the following function vs time (min):
Ln l(Ao - Af)l (At - Af)~
wherein said function is the oatuRal log of the ratio between the abso.; difference at initial time (Ao) and final time (Af) over the ~ -e d;rr~,.cnce at time t (At) and final time (Af)-Half-life as defined herein is the time required for half of the pro-fi~l~.~e to be hydrolyzed, and is d~,te. - - ~ from the observed rate constant (kob5) by the following function:
Ln (1/2) = -kobs t 1/2 Conventional Deter~ent ICL~ tS
In addition to the pro-fragrance e- , 1~s), the co~ ionc herein include a detersive ~u-ra~:t~t and optionally, one or more P~ itifn~ detergent ingredients, in~h-~ g materials for assisting or . ' g cleaning pe.ro. - e, t~tl~ t of the substrate to be cleaned, or to modify W O 97/34986 PCT~US96/04060 _15_ the ~~ ' cs of the deterge.,t comrocition (e.g., p_.~u,..es, colorants, dyes, etc.). The following are illustrative e~f .19s of detersive surfactants and other dete~g_l-t ingredients.
Detersive Surfactants Noo-limiting e~r ,13~ of synthetic detersive DUlL~r: useful herein typically at levels from about 0.5% to about 90%, by weight, include the ccs ~_ut.onal Cll-S C1g alkyl benzene 5~1ff- - ("LAS~) and primary, ts. ~ ' chain and random Clo-C20 alkyl sulfates (~AS~), the Clo-CIg ~ (2,3) alkyl sulfates of the formula CH3(CH2),~(CH(CH3)0S03 M ) and CH3 (CH2)y(CH(CH2CH3)0S03 M+) wherein ~ and y are integers and wherein each of ~ and (y + 1) is least about 7, preferably at least about 9, and M
is a water-s~h~bili7irlg cation, especially sodium, u ' ' sulfates such as oleyl sulfate, the 10 C10-Clg alkyl alko~y sulfates (~AEXS~; especially EO 1-7 etho~y sulfates), Clo-Clg alkyl alko~y carbo~ylates (especially the EO 1-5 etho~y~.~..yl, ), the Cl0-Clg glycerol ethers, the C10-C1g alkyl poly~ coD;d~s and their ccs..e.l~..d; ~g sulfated polyglycosides, and C12-CIg alpha-sulfonated fatty acid esters. If desired, the conventional nonionic and ~ ;c D.~ t such as the C12-Clg allcyl etho~ylates (~AE~); ~l .li,~g the so-called narrow peaked alkyl etho~ylates 15 and C6-C12 aL~yl phenol alkua~lat~ (especially etho~ylates and mi%ed etbo~y/p.o~,o~
C12-Clg betaines and r lru~ c (~sultaines~), Clo-Clg amine o~ides, and the like, can also be included in the overall ~o ~ t;c~ The Clo-Clg N-alkyl polyhydro~y fatty acid amides can also be used. Typical ~ . ' include the C12-Clg N u..,tl-yl~l c- - :d~c See WO 9,206,154.
Other sugar-derived Dulr~l~ltD include the N-alko1~y polyhydro~y fatty acid amides, such as Clo-C18 N-(3-metho~ypropyl) g' ~P The N-propyl through N-he~yl C12-C18 g' - ' can beused for low sudsing. Clo-C20 conventional soaps may also be used, however synthetic d,t~,r~tD are ~s.ef,.-cd. If high sudsing is desired, the l;- h-~ chain C10-C16 soaps may be used. Mi~tures of anionic and nonionic sulr~l~tD are especially useful. Other conventional useful s~-~r~,t~ub are listed in standard te~tts. See also U.S. Patent 3,664,961, Norris, issued May 23, 1972.
P~ef~ d cc~ c .ûccs.~~ only synthetic det~,.g. have a d_te;g level of from ahout 0.5% to 50%. Con~Q~ l; soap preferably co."p.;De from about 10% to about 90% soap.
Although the d~.t.,.~ herein can consist of only detersive s.. r.. ,~ul and 30 pro-f~ the said co~ iQnc preferably contain other mg.~l._.,t~ c~ 'y used in d~t.,.~ t products.
Builders - Detergent builders can optionally be included in the co--~ro~ nc herein to assist in controlling mineral hardness. Inorganic as well as organic builders can be used. Builders are typically used in fabric L~llùde.in~ :- . l - to assist in the removal of particulate soils.
The level of builder can vary widely d~.p~ ng upon the end use of the ccsu.~xs~ilion and its desired physical form. When present, the cc ~pO~i~jQnc will typically ccs.~.l"ise at least about 1 % builder. Liquid for n~ nc typically comprise from about 5 96 to about 50 %, more typically about 5% to about 30%, by weight, of detergent builder. Granular ~, l nnc typically comprise from about 10% to about 80%, more typically from about 15% to about 50% by weight, of the d~,te.~ t builder. Lower or higher levels of builder, however, are not meant to be p~ rlP~
Inorganic or dete(~_nt builders include, but are not limited to F'~ builders such as, the alkali metal, _ - and l' l- salts of polyl.ho~l,h~ (e~PmrlifiPA by the tripol~r"!~~.' ~, p~ h-.L ~ and glassy polymeric meh-phnspb~-tPs), l.hf,~l,h.'~ ., and phytic acid, and noa pho~horous builders such as silicates, ca.l,o..at~. (in~ ing ~: l~nat~s and se~ houatc~s)~ t~ 5~ and ~ minocilicA~pc Non-pllo~l.h~e builders are required in some 10 locales.
Organic builders suihble for use herein include polycarho%ylate builders such as Aic~Aln~d in U.S. Patent 3,308,067, Diehl issued March 7, 1967; 4,144,226, Crutchfield issued March 13, 1979 and 4,246,495, Cru'~hfiPl~l. issued March 27, 1979.
Soil Release A~ents Soil Release agents are desirably used in laundry d~,te~en6 of the inshnt i~ .Jtioll.
Suitable soil release agents mclude those of U.S. 4,968,451, November 6, 1990 to J.l. Scheibel and E.P. Gn~CplinL such ester oligomers can be prepared by (a) etho~cylating allyl alcohol, (b) reacting the product of (a) with dimethyl t~ l9~ DMT") and 1,2 ~..o~,~h,ne glycol (~PG~) in a two-stage Ir ~ ~~ f- /olig~ t; a plocedu.G and (c) reacting the product of (b) with 20 sodium _ tab; 'fitç in water; the nonionic end-capped 1,2-propylene/polyo~_lL.~lene t~ r~ pol~_.t~..D of U.S. 4,711,730, December 8, 1987 to Go ~~' '~ et al, for e%ample those l,.u.lu~ by l ~ ;fication/olig~ i~lion of poly(ethyl~ lycol) methyl ether, DMT, PG and poly(eth.~l negl~col) (~PEG"); the partly- and fully- anionic-end-capped oligc ic esters of U.S. 4,721,580, lanuary 26, 1988 to Gosselink, such as oligomers from ethylene glycol 25 (~EG~), PG, DMT and Na-3,6-dio%a-8-hydro%~ - Ifonate; the nonionic-capped block pol~ oligompric c~ s of U.S. 4,702,857, October 27, 1987 to Gosselink, for e%ample ~,.. ' ,d from DMT, Me-capped PEG and EG andlor PG, or a, ' ~ of DMT, EG and/or PG, Me-capped PEG 9nd Na-dimethyl-5-sulfsJ;~ph~ ; and the anioaic, especially sulfoaroyl, e ~ r ~d t~ sls~P esters of U.S. 4,877,896, October 31, 1989 to M-'-lnn~lo, Gnc.cPlin~- et 30 al, the latter being typical of SRA's useful in both laundry and fabric cf~ndi~inning products, an e%ample being an ester c~ ;tjn~l made from m-sulf.t~nzoic acid ...nnnC.~ salt, PG and DMT optionally but preferably further co."p.-Dmg added PEG, e.g., PEG 3400. Another preferred soil release agent is a 5l~1f~- d end-capped type described in US 5,415,807.

35 Other Ol~tional I..~ .~dic.~tD

W O 97/34986 PCT~US~6,'~0G0 The c~ herein can contain other ingredients such as enzymes, bl-- ' 5, fabric softening agents, dye transfer inhibitors, suds ~u~ os~ls, and chelating agents, all well known within the art.
For purposes of defining dete.~,out cc ~ one of the present invention, the pH of the S d_tel~c.,t cc~rc- is that which is ~- ~d at 1% collcenl~lion of the dete,~e.~t C(J...~
in distilled-water at 20~C. The d~_ter~eAt co- .ln,~;lions herein have a pH of from about 7.1 to about 13, more typically from about 7.5 to about 9.5 for liquid detc~ b and from about 8 to about 12 for granular d~,t~ ;ent~.
Formulation with Detc. 2.~.1t~ With or Without Convention~l Pc. rl"~,c. Y Materials While the pro-fragrances of the present invention can be used alone and simply mi~ed with essential detergent ingredient, most notably ~Jlr~l~t, they can also be d~;~bly c~
into llu~ pall ful ' tinn~ which combine (a) a non-fragranced dete,g_ base c< u.".i~h~g one or more synthetic dete~ (b) one or more pro-fragrant acetals or ketals in acco.d ~ with the hu~ ;nn and (c) a fully-fiu. ' ~ ~ d fragrance. The latter provides desirable in-package and in-use 15 (wash-time) f~_g. -~, while the pro-r. g ~e provides a lon& tC.I~. fragrance to the I '- ~d te~tile fabrics.
In rul '- ~g the present d.,t."~,. the fully-formulated rl..~j -e can be prepared using - oùs known odorant ~hg~lic.~b of natural or synthetic origin. The range of the natural raw ~ A can embrace not only readily-volatile, but also mod~ -volatile and 20 slightly-volatile cc.~ n~ and that of the s~ulh~tics can include ~ res from p.. :t - 11y all classes of fragrant ' - , as will be evident from the following illustrative ~ ~ . l ,1 -natural pr~ h . such as tree moss absolute, basil oil, citrus fruit oils (such as ~.~, t oil, ' in oil, etc.), masti~ absolute, myrtle oil, palmarosa oil, F ' ' Lli oil, pe~itgra;n oil P~". ~y, wu~ ..Jod oil, alcohols, such as farnesol, geraniol, linalool, nerol, phenylethyl 25 alcohol, rhY~ nl, cinnamic alcohol, aldehydes, such as citral, HelionalTJ, ~'p~- ' yl-c ldPhyde~ hydro~ycitronellal, LilialTU (p-tert.butyl-alpha -methyldihydl. ld~hyde), r.~t~ hyde~ ketones, such as allylionone, alpha-ionone, beta -ionone, isoraldein(i~uu_lh~l- alpha -ionone), ' ylionono, esters, such as allyl Fh ~ q ~, benzyl salicylate, cu~~ l pl~. , citronellyl acetate, citronellyl o~hn~c', decyl acetate, 30 dimethylbenzylc~ l acetate, di~.._Ll~llJ_~lcarbinyl butyrate, ethyl ~ ~ , ethyl ac~l~la: he~enyl isob~ , linalyl acetate, methyl dihy.ln>j i ~, styrallyl acetate, vetiveryl acetate, etc., lactones, such as L -~n~Al~~tone, various c~ n~n~ often used in p~.- ruu,_. ~, such as musk ketone, indole, p - 8 thiol-3-one, and methyl-eugenol.
Likewise, any conventional fragrant acetal or ketal known in the art can be added to the present 35 co ~ n as an optional co..~ t of the conventionally formulated perfume (c). Such co~ tiondl fragrant acetals and ketals include the well-known methyl and ethyl acetals and ketals, as well as acetals or ketals based on b~n~ Phyde, those Co~ .g phenylethyl moieties, W O 97/34986 PCT~US96/04060 or more recently d~,velo~d cpe~isl~ies such as those described in a United States Patent entitled ~Acetals and Ketals of Oxo-Tetralins and Oxo-lndanes, see U.S. Pat. No. 5 ,084,440, issued January 28, 1992, assigned to Givaudan Corp. Of course, other recent synthetic cperiqlti~C can be included in the perfume co..~ iti~.nc for fully-ro. ' ~ ~ dcte(g_..h. These include the enol S ethers of alkyl ~b~ o~o t~,t. ': ~ and oxo-indanes s described in U.S. Pat. 5,332,725, July 26,1994, assigned to Givaudan; or Scbiff Bases as described in U.S. Pat. 5,264,615, December 9, 1991, assigned to Givaudan. It is p.ef~ d that tbe pro-fragrant material be added separately from the conventional f~ .~ces to the dete.~e.-t con~citi~nC of the invention.
Formulation with other SPecial-Purpose T~ . Deliverin~ Compounds Detergents in acco.J u~ce with the present invention may further, optionally, if desired, contain otber known cc~ baving the capability to enhance s-' vily of a r,~. Je Such c.~ include, but are not limited to, the Pl qll~o~ c such as isobutylsl dife. y' ~ as diselosed in U.S. Pat. 4,055,634, iswed October 25, 1977 and assigned to Hoffrnan-La Roch; or the known titanate and ~.-. ~ ~ esters or oligoesters of fragrant ~ ials such as those diC~loc-~d in U.S. Pat. 3,947,574, Jaggers et al, issued March 30, 1976 and U.S. 3,779,932, Jaggers, issued De ' r 18, 1973. When using such organoah ~
o,~, t;~ or GIL ~ - derivatives, they may be inco.~,~,.atcd into the pre~nt ro,,....l ~ nc at their art-known levels.
Methods of Use In its method aspect, the present invention can be described as:
A method of delivering residual fi..~;. ~ ~e to a washed surface which co..~ c the steps of (a) washing said wrface in an aqueous solution of a d~ te.~,_"t Co~ ioD
~~ . 3 (i) apro-fragrant ~ f ~ selected fromthegroup c~ e of acetals, ketals, and mi~tures thereof, said pro-fragrant c~ having;
(1) a r ' ' ~ weight of at least about 350, (2) a CLogP of at least about 4, wherein CLogP is the IG~.al" tO
base 10 of the octanol/water partition co. frn ;~.. Jt of said pro-fragrant ~ . 1, and (3) a half-life of less than 60 minutes, when ~~ ~ at pH 0 by the Pro-Fragrant Hydrolysis Test; and (ii) a detersive ~u,r ', wherein said d~tel~nt co~.l.o~;lion has a pH of at least 7. I when measured as a1 % solution in distilled-water at 20 C;
b~ l.y e~cposing said wrface to a ..i~U ic in pH.

W O 97/34986 PCT~US9~J~10C0 EXAMPLES
EXAMPLE l Prep~~r~iorl of Didecyl Anisaldehyde Acetal by Acid Catalysis In a 500 ml single necked round bottom flask ~Cs~ml~l~ with a Dean-Stark trap and S C~ . A~ ~ under a nitrogen ~ p~ c, ' ~ ohyde(21.3g, 0.156 mol), decanol (98.8 g, 0.627 mol, 4 eq.), andpara toluene sulfonic acid (0.30 g, l mol%) are dissolved in 150 ml toluene and brought to reflu~ until starting aldehyde is cc . ' I 'y CO~ f~ Upon cooling, the reaction mi~ture is washed three times with saturated sodium c~ followed by drying with ~hylluu~
g sulfate. The solvenl is removed under reduced pressure, and u".~,t~,d parent co.. l~u ~lc are removed under bulb-to-bulb dis~ i( n at 60-80~C, 0.4 mrn Hg, yielding 48.1 g of a brown oil (71%). The acetal is then further purified by column ~ L~ - ~6.,.~Jhy on 230-400 mesh 60 A silics gel eluting with 4% ethyl acetate/ 1% triethylamine/ petroleum ether yielding a yellow oil (43.2 g, 64% yield). t 1/2 at pH 0 is less than 1 minute. CLogP is 11.09.

P.~, t; of Digeranyl Citral Acetal Using T ~ q~ n In a 500 rnl single necked round bottom flask --- ' le1 with a short path ~lic~ n ~PI~ h ~ under a nitrogen - ,~r' c, citral dimethyl acetal (41.0 g, 0.21 mol), geraniol (100 g, 0.65 mol,3.2 eq.) and titanium isopr~po~fide (3.0 g, 5 mol %) are dissolved in 200 ml of toluene and brought to reflw~. Toluene is distilled off as a means to a~t.op;~ lly remove . ,lh ol from the reactiûn rni~ture. Si~ 150 ml portions of toluene are added to the reaction mi~ture and distilled ûff over the course ûf 10 hours until TLC shows the reaction is c. 1,1 I The re~ n; ,g toluene is removed under reduced pressure, and u~ea't~ parent c~ po~ are removed by bulb-to-bulb diC~ at 65-85 ~C, 0.4 rnm Hg, yielding a yellow-brown oil. The product is then further purified by column ~ .hy on 230-400 mesh 60 A silica gel eluting with 2% ethyl acetate/ 19~ tr;_L~ ' ~tl~ l ether yielding a yellow oil (59 g, 67% yield). t 1/2 at 0 pH
is less than one rninute. CLogP is 9.75.

P.c. ~ n of the Didecyl Ben_yl Acetone Ketal by Acid Catalysis In a 500 ml single necked round bottom fla k ~ -'le~ with a Dean-Stark trap and c- ' r under a nitrogen o~ ph~.c, benzyl acetone (13. lg, 0.088 mol), decanol (51.7g, 0.33 mol), and para-toluene sulfonic acid are dissolved in 100 ml toluene and brought to reflw~. After 24 hours, the water is removed from the Dean-Stark trap, and the trap is filled with 3 A activated Ic a! sieves (J.T. Baker). The reaction mixture is refluxed for an P~ itionql 24 hours. After cooling, the reaction mixture is washed three times with saturated sodium c~,l,onatc and dried over ar~yl.u~ ~,_ sulfate. The toluene is removed under reduced pressure followed by W O 97134986 PCT~US96/04060 removal of u.. ea~t~d parent co ~l o~ k by bulb-to-bulb diCti1l tion at 65-85 ~C, 0.4 mm Hg yieldiog a yellow oil (15.8g, 38% yield). t 1/2 at 0 pH is less than one minute. CLogP is 11.65.

Preparation of the Digeranyl Decanal Acetal By Acid Catalysis 5 In a 1 L single necked round bottom flask r~ 'le~? with a Dean-Stark trap and con~lRnC~r under a oitrogen ~ h .e, decanal (50 g. 32 mol.), geraniol (197.4 g, 1.28 mol, 4 e~.) .) and anhydrous citric acid (6.14g, 0.032 mol) are dissolved in 320 ml toluene and refluAed for 24 hours. Upoo cooling, the reaction mixture is washed three times with saturated sodium c~
followed by dryiog over - sulfate. The solvent is removed under reduced pressure, and 10 eAcess geraniol is removed under bulb-bulb diC~ on at 60-80~ C, O.lmm Hg, giviog a clear yellow oil (132.1g, 92% yield). t 1/2 at 0 pH is 44 ~ ' ~. CLogP is 11.66.

Granular Laundry Comr~;~ion delivering Geraniol from Digeranyl Citral Acetal Pro-f _ e of EAample2 1.0%
Cll-C13 Dodocyl Benzene S~lf- 21.0%
C12-C13 AL~eyl F-' y' ~ EO 1-8 1.2%
Sodium Tripol~ "h-, '~ 35.0 %
Zeolite Na 4A 14.0%
Sodium Silicate 2.0 ratio 2.0%
Sodium Carbonate 23.4%
Enzyme (Sa~ /orLipolascT" 1 4%
from Novo) r I VA~ tlJyl C~~ Se 0.3 %
Anionic Soil Release Agent * 0.3 %
Brightener 0.2%
Silicone Suds S.. ~",.~or ~ 0.2%
Perfume ~ 0.3%
Sodium Sulfate 0.5 %
Moisture balance * Soo U.S. 4,968,451 ** CGIII...C~jal material available from Dow Corming Corp.
~Pe.r~ .eC~ on of the following formula:

W O 97/34986 PCTAJS~010C0 Benzyl salicylate 20%
EthyJene b.~.~ i 20~o Gqls~ le (50% soln. in benzyl benzoate~ 20%
S He~yl cirmamic aldehyde 20%
Telrahydro li~alool 20%
100%

10 Granular Laundry Detergent Delivering Anisaldehyde from Didecyl Anisaldehyde Acetal Pro-f,~. : of E~ample 1 1.0%
Linear Dodecyl Benzene S~lf~- ~ 21.0%
Neodol 23-6.5 - Nonionic Su.r~ck~t 1.2%
Sodium Tripol~ 35.09~
20 Zeolite 4A 14.0%
Sodium Silicate 2.0 ratio 2.0%
Sodium Carbonate 23.4%
Enzyme (SavinaseT~ and/or Lipolase~ 1.5 %
from Novo) Ca.l,v~ l CP~ s, 0.3%
Anionic Soil Release Agent~ 0.3%
~n~'' 0.2%
35 Silicone Suds Su~ 0.2%
(See footnote in E~. 5) r~.ru~ 0.3%
(See footnote in E~ample 5) Sodium Sulfate 0.5 %
Moisture balance 45 ~ See U.S. 4,968,451 W O 97/34986 PCTAUS961~'~C~0 Laundry Detergent Cû~pr;s~g Pro-Fragrance and Fully-Formulated Perfume Comrscition having a Conventional Ketal f.ag.~ce C'o~ l~,rf t A laundry d~,t~.g~ '9n j5 prepared by weighing 98 grarns of laundry dete.~ .t according to E~ample 6 with the PTrerti~n that perfume and pro-fr..gr~tce are not inrul~hd;
5 :~1mi~ing to said co...l.n~;l;nn2 grams of a perfitme of flowery-woody type made up of a mhcture of a first premi~ and a conventional ketal (not in accor~nce with essential pro-fragrance as defined herein) as follows:
First Premi~:
Oil of ~al~Ot 7.5 Linalool 4 0 Phenyl ethyl alcohol 4.0 Benzyl acetate 2.0 Citronellol 0.5 Hedione~ (a) 10.0 LyralT~ (b) 4.0 Hydroa~c;ttuuellal 2.5 Rose o~ide 1 (c) 10% in DPG 2.5 He~yl ~ ~- - aldehyde, alpha 7.5 y Oil 1.-~ 4.0 Iso-ET~ (b) 2.0 Vetiveryl acetate 2.0 Bl ' -ITM F (c) 2.0 Benzyl Salicylate 2.0 cis-3-He~enyl Salicylate 1.0 C~ ~ (b) 1.0 Musl~ Xylene 1.0 Indole 10% in DPG 0.5 E~tract of Opoponas 0.5 E~tract of Oakrnoss 50% in DPG 5.0 (a) Firmenich (b) IFF
(c) DRAGOCO
Total Parts by weight of First Premi~: 68.0 The first perfnme premi~ is modified by adding to it 32 parts by weight of Sal5b (80:20) wherein 5a is 5-ethylenedio~y-3.beta.-H-isolongifolane and 5b is 5-ethylenedio~y-3.alpha.-H-isolongifolane; these two . . '~ being conventional perfurne ketals not in acco.d~ce with the present invention, and their synthesis is described in ~CYCLIC ISOLONGIFOLANONE-KETALS

W O 97t34986 PCT~US96/04060 - THEIR MANUFACTURE AND THEIR APPLICATION~, U.S. Pat. No. 5,426,095, issued June 20, 1995 to Brunke and Schatkowski, assigned to Dragoco.
1.0 grams of a pro-fl..E~ce accGl.li..g to Example 2 is mixed into the powdered, ~.ru.l.c-free d~t.,.~_nt co--q~ n Finally, about 1.5 grams of the above perfume comro~ n~
S is sprayed onto the mi~ture of det~r~~ ~ and pro-fragrance, to complete the fragranced, pro-fragranced laundry detergent cc .po~ n The said composition has a floral-woody character and leaves an improved, long-lasting scent on te~tile fabrics washed therewith.

Detergent having the form of a Laundry Bar Comprising Pro-Fragrance Pro Fragrance of E~ample 1 1.0 %
Tallow Soap~* and Coco Soap Mi~ture (80:20) 44.0%
15 Linear Dodecyl Benzene Sulfonate 12.0%
Sodium Tripolyl t- p~ ~ 6.0%
Sodium Carbonate 8.0%
Sodium Sul6te o.5%
Talc 9.0%
25 r~.ru~ 0.2%
Moisture balance ~ Iodine Value = 40 30 ~**See footnote ~n E~ample S

Liquid Detergent Cclu~ ing Pro-Fragrance Pro F.. g. -e of E~ample 1 1.0%
Sodium C12-ClS Alcohol Etho~ylate E 2.5 Sulfate 18.0%
Neodol 23-9 Nonionic r r~t 2.0%
C12 ALkyl N-Meth~l~,' '~ S.0%
Sodium Cumene S~kr- ~ 3.0%

Citric Acid 3.0%
Fatty Acid (C12-C14) 2.0 %
Boric Acid 3.5%
Sodium Hydro~tide 2. 8 %
E~A~ldt~d T~t, ' yl~nePen~imi~ 1.2%

W O 97/34986 PCT~US96/04060 Soil Release Polymer O. lS %
1,2-P.u~ l 8.0%
Ethanol 3.6 %
MnnnP-~ ~lqrn;n................ l. l %
Minor_~ 1.80%
Water Balance *Minors include brightner and enzymes Although the ~mpl~~ illustrate the invention _s described, those skilled in the art will be 10 able to recognize that ~al cnC thereof are fully within the scope of the hl~ l. In one such variation, the practioner will minimi7~ the m~'~culqr weight while still seeking the a l ~ ~s of the invention, for e~ample by selecting pro-fia~ldnccs at-l/2 of less than one rninute at pH 0.

Claims (15)

WHAT IS CLAIMED IS:

1. A detergent composition for imparting residual fragrance to surfaces washed with aqueous solutions of said detergent, said detergent comprising:
(a) a pro-fragrant compound selected from the group consiting of acetals, ketals, and mixtures thereof, wherein at least one of the parent aldehydes, ketones, or alcohols of said pro-fragrant acetal or ketal is a fragrance compound, said pro-fragrant compound having;
(i) a molecular weight of at least about 350, (ii) a CLogP of at least about 4, wherein CLogP is the logarithm to base 10 of the Octanol/Water Partition Coefficient of said pro-fragrant compound, and (iii) a half-life of less than 60 minutes, when measured at pH 0 by the Pro-Fragrant Hydrolysis Test; and (b) a detersive surfactant;
wherein said detergent composition has a pH of at least 7 when measured as a 1% solution in distilled-water at 20°C.

2. The composition of Claim 1 wherein the CLogP is at least about 6.

3. The composition of Claim 2 wherein at least one parent alcohol of the pro-fragrant compound is selected from the group consisting of C6 to C20 saturated or unsaturated, linear or branched alcohols, and alkoxylates of said alcohols wherein the alkoxylate moiety contains from 1 to about 30 alkoxy groups selected from ethoxy, propoxy, butoxy and mixtures thereof.

4. The composition of Claim 2 wherein tbe pro-fragrant compound is a monoacetal.

5. The composition of Claim 4 wherein the acetal is selected from the group consiting of digeranyl citral acetal; di(dodecyl) citral acetal; digeranyl vanillin acetal; didecyl hexyl cinnamaldehyde acetal; didecyl etbyl citral acetal; di(dodecyl) ethyl citral; didecyl anisaldehyde acetal; di(phenylethyl) ethyl vanillin acetal; digeranyl p-t-bucinal acetal; didecyl triplal acetal;
di(dodecyl) triplal acetal; digeranyl decanal acetal; di(dodecyl) decanal acetal; dicitronellyl laural acetal; di(tetradecyl) laural acetal; di(octadecyl) helional acetal; di(phenylethyl) citronellal acetal;
di(3-metbyl-5-phenyl pentanol) citronellal acetal; di(phenylhexyl) isocitral acetal; di(phenylethyl) floralozone acetal; di(2-ethylhexyl) octanal acetal; di (9-decenyl)p-t-bucinal acetal; di(cis-3-hexenyl) methyl nonyl acetaldehyde acetal and di(phenylethyl) p-t bucinal acetal.

6. The composition of Claim 2 wherein the pro-fragrant compound is a monoketal.

7. The composition of Claim 6 wherein the pro-fragrant compound is a ketal selected from the group consisting of di(phenyl ethyl) alpha ionone ketal; di(dodecyl) alpha ionone ketal; di (phenyl hexyl) beta ionone ketal; di (citronellyl) gamma methyl ionone ketal; di(tetradecyl) gamma methyl ionone ketal; didecyl methyl beta naphthyl ketal; dioctadecyl cis jasmone ketal; digeranyl damascenone ketal; di(cis-3-hexenyl) methyl dihydrojasmonate ketal; di(dodecyl) methyl dihydro-jasmonate ketal; didecyl benzyl acetone ketal; di(2-ethylhexyl) methyl amyl ketal;
di(dodecyloxyethyl) methyl amyl ketal; di(octadecyl) carvone ketal; and digeranyl geranyl acetone ketal.

8. The composition of Claim 2 wherein the composition is a granular detergent having a pH
of from about 8 to about 12 and wherein the pro-fragrant compound has a half life of less than 1 minute when measured at pH 0.

9. The composition of Claim 8 wherein the pro-fragrant compound has a half life of less than one minute when measured at pH 2.

10. The composition of Claim 2 wherein the composition is a liquid detergent and wherein the pro-fragrant compound has a half life of less than 60 minutes when measured at pH 0 and a half life of greater than 1 minute when measured at pH 2

11. The compositions of any one of Claims 1 to 10 wherein the composition comprises from 0.5 % to 50 % detersive surfactant and from 0.001 % to 5 % pro-fragrance.

12. A pro-fragrance selected from the group consisting of acetals, ketals and mixtures thereof, wherein at least one of the parent aldehydes, ketones, or alcohols of said pro-fragrant acetal or ketal is a fragrance compound, said pro-fragrant compound having:
(i) a molecular weight of at least about 350, (ii) a CLogP of at least about 4, wherein CLogP is the logarithm to base 10 of the Octanol/Water Partition Coefficient of said pro-fragrant compound, and (iii) a half-life of less than 60 minutes, when measured at pH 0 by the Pro-Fragrant Hydrolysis Test;
provided that said parent aldehyde, ketone or alcohol of said acetal or ketal comprises at least one compound selected from the group consisting of a) aldehydes, ketones and alcohols containing at least one aromatic moiety selected from the group consisting of C6H4 and C6H3 and wherein said parent aldehyde or ketone has a molecular weight of at least 125;
b) monoalcohols selected from the group cnncicting of C11-C20 saturated, unsaturated, aromatic, aliphatic linear and branch chain alcohols and alkoxylates of said alcohols containing from 1 to about 30 alkoxy groups wherein said alkoxy isselected from the group consisting of ethoxy, propoxy and butoxy and mixtures thereof;
c) polyhydroxy alcohols, and d) mixtures thereof.

13. A compound of Claim 12 selected from the group consisiting of di(dodecyl) citral acetal;
digeranyl vanillin acetal, didecyl hexyl cinnamaldehyde acetal; di(dodecyl) ethyl citral acetal;
didecyl anisaldehyde acetal; di(phenylethyl) ethyl vanillin acetal; digeranyl p-t-bucinal acetal;
di(dodecyl) triplal acetal; di(dodecyl) decanal acetal; di(tetradecyl) laural acetal; di(octadecyl) helional acetal; di(3-methyl-5-phenyl pentanol) citronellal acetal; di(phenylhexyl) isocitral acetal;
di(phenylethyl) floralozone acetal; di(9-decenyl)p-t-bucinal acetal) di(phenylethyl) p-t-bucinal acetal; di(dodecyl) alpha ionone ketal; di(phenyl hexyl) beta ionone ketal; di(tetradecyl) gamma methyl ionone ketal; dioctadecyl cis jasmone ketal; di(dodecyl) methyl dihydrojasmonate ketal;
didecyl benzyl acetone ketal; di(dodecyloxyethyl) methyl amyl ketal, and di(octadecyl) carvone ketal.

14. A method of delivering residual fragrance to a washed surface comprising the steps of:
(a) washing said surface in an aqueous solution of a detergent composition comprising (i) a pro-fragrant coumpound selected from the group consisting of acetals, ketals, and mixtures thereof, wherein at least one of the parent aldehydes, ketones, or alcohol of said pro-fragrant acetal or ketal is a fragrance compound, said pro-fragrant compound having;
(1) a molecular weight of at least about 350, (2) a CLogP of at least about 4, wherein CLogP is the logarithm to base 10 of the Octanol/Water Partition Coefficient of said pro-fragrant compound, and (3) a half-life of less than 60 minutes, when measured at pH 0 by the Pro-Fragrant Hydrolysis Test; and (ii) a detersive surfactant;
wherein said detergent composition has a pH of at least 7.1 when measured as a 1% solution in distilled-water; and (b) subsequently exposing said surface to a reduction in pH of at least 0.1 pH units.

15. The method of Claim 13 wherein the pH in Step(b) is reduced by at least 0.5 units to a pH
of 7.5 or less.