US3755085A - Prevention of enzyme deactivation by chlorine - Google Patents

Abstract

Enzyme deactivation during fabric laundering in water is prevented by using the enzyme in combination with a chlorine scavenger which is capable of reacting with residual chlorine in the water.

Description

United States Patent [191 Tivin et a1.

l PREVENTION OF ENZYME DEACTIVATION BY CHLORINE [75] Inventors: Fred Tivin, Springfield Twp.; Eugene Zeffren, Wyoming, both of Ohio [73] Assignee: The Procter & Gamble Company,

[52] U.S. Cl 195/68, 195/63, 252/89,

252/D1G. 12 51 Int.Cl ..C07g 7/02 [58] Field of Search 195/63, 68, 66;

[451 Aug. 28, 1973 [56] References Cited UNITED STATES PATENTS 3,189,518 6/1965 Glasgow 210/62 X' Primary Examiner-David M. Naff Attorney-Julius P. Filcik and Richard c. Wine [57] ABSTRACT v Enzyme deactiyation during fabric laundering in water is prevented by using the enzyme in combination with -21 chlorine scavenger which is capable of reacting with residual chlorine in the water.

2 Claims, No Drawings PREVENTION OF ENZYME DEACTIVATION BY CHLORINE FIELD OF INVENTION BACKGROUND OF INVENTION AND PROBLEMS CONNECTED THEREWlTl-I Enzymes are organic catalytically-active protein materials which in very low amounts speed up certain chemical reactions. One of their known functions is to I break down various types of organic matter (carbohydrates, fats, proteins) into simpler particles, e.g., enzymes that are found in the human digestive system break down food materials into smaller, more assimilable forms. When used in detergent compositions, the enzymes function to break down soils and stains into simpler forms so they can be more easily removed by other detergent ingredients and the washing action.

Enzymes are complex molecules and are subject to attack and deactivation by many different conditions which prevail depending upon the different applications of the enzymes. For instance, incompatibility of enzymes and detergent ingredients such as chlorine bleaching agents is recognized; for example, an article published in Detergent Age, September, 1968, by Dr. Howard E. Worne, titled The Role of Enzymes in Detergent Compositions states:

Bleaching agents such as perborates, peroxides, or

compounds containing active chlorine, strongly inhibit the reaction of proteolytic enzymes, and as such, they must be eliminated from all proposed formulations. v

For this reason, care is exercised in formulating detergent compositions in which an enzyme component is contemplated. US. Pat. No. 3,451,935 discusses some highly useful ways of overcoming the problems I encountered. While this latter discovery has advanced the art materially and has provided, for the first time, large scale production of genuinely effective granular enzyme-containing detergent compositions, it has more recently been discovered that additional problems are encountered in actual usage situations.

Further evaluations have shown that the full potential benefit of enzymatic activity in detergent compositions has not always been enjoyed in practical ordinary household situations. The reason for this has gone unrecognized until the present invention.

It has now been discovered that enzyme activity can besubstantially decreased by deactivation of the enzyme component by even small amounts of residual chlorine present in domestic water supply sources. It is this heretofore unappreciated problem that is solved by the present invention.

There are two basic ways of treting waste as part of pollution control in the United States. They are referred to generally as primary and secondary treatments. In a primary treatment, solids are allowed to settle and are removed from the water. The secondary treatment method uses biological processes. A common step in both of these treatment methods involves the addition to the water of varying amounts of free available chlorineas gaseous chlorine or hypochlorites.

A major purpose for the chlorine addition is to kill disease producing bacteria, although it also helps to reduce odors. I

While a portion of the added chlorine escapes from the water during the treatment and handling steps, it has been found that a portion of residual chlorine remains in municipal water-supplies. This residual chlorine is sufficient to substantially deactivate an enzyme when it is added to such water.

A major object of this invention is to provide significantly improved benefits in the area of cleaning and laundry performance results obtained with enzymecontaining detergent compositions. While detergent compositions and washing processes represent preferred embodiments of this invention, it, in fact, finds wider application. The invention can be applied broadly to all enzyme usages in water which contains residual chlorine.

SUMMARY OF THE INVENTION AND PREFERRED EMBODIMENTS It has now been discovered that the deactivation of an enzyme by residual chlorine in water can be prevented by using the enzyme in combinationwith a hydroxyamine chlorine scavenger which is capable of reacting with. the residual chlorine to form chloramines.

The hydroxyamine chlorine scavenger of the present invention has the following formula:

wherein each of R", R, and R is selected from the group consisting of hydrogen, and alkyl or hydroxyalkyl groups having from 1 to 6 carbon atoms. The alkyl groups can be straight'chainor branch chain and the hydroxy can be present on any of the carbon atoms.

The following compounds are illustrative of those which can be used in practicing the present invention:

methylamine,

ethylamine,

l -propylamine,

l-butylamine,

l-pentylamine,

3-amino-l-propanol,

l-amino-Z-propanol, l-amino-2-butanol,.

l.-amino-3-butanol,

l -a.mino-4-butanol,

I-amino-Z-pentanol,

1-amino-3-pentanol,

l-amino-4-hydroxypentane,

l-amino-S -hydroxypentane,

2-amino-2-methyll -propanol,

2-amino-2-methyll -butanol,

2-amino-2-methyll -penta.nol,

2-amino-2-methyll -hexanol,

2-amino-2-methyll ,3-butanediol,

Z-amino-Z-methyl-l ,4.-butanediol,

2-amino-2-methyl-l ,3-pentanediol,

2-arnino-2-methyl-l ,4-pentanediol,

2-amino-2-methyl-l ,5 -pentanediol,

2-amino-2-methyl-l ,3'-hexanediol,

2-arnino-2-methyl-l ,4-hexanediol,

2-amino-2-methyl-1,5-hexanediol,

2-amino-2-methyl-l ,6-hexanediol.

2-aminol ,3-propanediol,

2-amino-2-methyl-l ,3propanediol,

2-amino-2-hydroxymethyl- 1 -butanol,

After neutralizing the catalyst and stripping off unreacted formaldehyde, the nitroalcohol is vnext reduced over Raney nickel to the corresponding amine. Carbon dioxide is added to the hydrogen stream in the reduction process to neutralize the amine as it is formed. Thisv prevents side reactions which would'otherwise occur between the amine and the nitroalcohol.

Aminohydroxy compounds which are representative of the type which are useful in the present invention are further described below:

mcth yl-lmethyl-1,21- ethyl-1,3, tris(hy lrx ymethyl Physical properties 2-amino-1-butanol pro panol propanediol propanediol amlnomethang Formula z N NH: NH: NH;

Molecular weight 89.1 105.14 119. 17 121. 14

Boiling point, C 178 165 mm 151-152 mm 152-153 219-220 Melting point, C .t -2 30-31 109-111 37. 5-38. 5 171-172 Specific gravity at /20 C 0. 944

pH 010.1 M aqueous solution at 20 C... 11.1 11.3 10. 8 10.8 10. 4

Solubility in water at 20 0., g./10O m1. 250 80 1 Completely miscible.

2-amino-2-hydroxymethyl-1,S-hexanediol,

2-amino-2-hydroxyrnethyl-1,-hexanediol,

1 -amino-1 -ethanol,

Z-amino- 1 -propanol,

Z-amino- 1 -butanol,

2-amino-1-pentanol,

Z-amino- 1 -hexanol 2-amino-1,4-butanediol,

2-amino-l ,3-butanediol,

2-amino-1,3-pentanediol,

2-amino-1 ,4-pentanediol,

Z-amino-l ,S-pentanediol,

2-amino-l ,3-hexanediol,

Z-amino-l ,4-hexanediol,

2-amino-1,5-hexanediol,

2-amino-l ,6-hexanediol.

The hydroxyamines of the present invention can be prepared by many different syntheses. One satisfactory general method involves reacting a nitroparraffin with formaldehyde in the presence of a caustic catalyst to yield a nitroalcohol. This reaction is a condensation of the aldol type in which one, two or three of the hydrogen atoms attached to the carbon atom holding the nitro group may add to the oxygen of the formaldehyde with the formation of hydroxy methyl-substituted nitroparaffins.

THe following equations illustrate the general application of this type of a reaction:

Further suitable. synthesis procedures are found in the following patents and technical literature references: U.S. Pats, No. 2,755,304 granted July 17, 1956, and No. 2,946,793 granted July 26, 1960; Japanese Pat. No. 1,235, dated Feb. 24, 1955 Preparation of amino alcohols found in comp. rend. congr. sci. savantes Paris etdepts, Sect. sci. 1955, 89-93; Great Britain Pats, No. 764,183 published Dec. 19, 1956; No. 758,941 published Oct. 10, 1956; No. 760,215 published Oct. 31, 1956; No. 839,317 published June 29, 1960; Preparation of B-amino alcohols described by J. H. Hunt and D. McHale (Allen & Hanburys, Ltd., Herts, Engl.) J. Chem. Soc. 1957, 2073-7; West Germany Pat. No. 1,096,917 published Jan. 12, 1961.

The invention can be practiced according to several embodiments. Preferably, an enzyme composition is prepared embodying the invention. Such a composition comprises a mixture of an enzyme (either a pure enzyme or an ordinary enzyme preparation consisting of a powder mixture of an activeenzyme ingredient and inert salts which are ordinarily found in commercial enzyme preparations such as, for example, sodium and calcium sulfates) and a hdyroxyamine chlorine scavenger of the type specified above. The amount of each ingredient depends on the use of the composition. For maximum benefits, there should be an amount of hydroxyamine chlorine scavenger sufficient to overcome the residual chlorine. For any given purpose, the

N itroparaifin Formaldehyde Intermediate aldol product CH=NO1 plus SCHzO N02 CHzOHC CHzOH CHzOH (N itromcthane) (tris(Hydroxymethyl)nitromethane) (l-nitropropane) 1CH2O NO; NO; OHJCHCHS 011380112011 (.Zqutropropane) (2-nitro-2-ethyl-1,3-propanediol).

(2-nitro-2-methyl-1-propan01).

Another important aspect of the present invention is the totally unexpected discovery that when the amount of hydroxyamine chlorine scavenger in a detergent product exceeds the amount of residual chlorine in wash water .(on a molar basis), I the enzyme stainremoval cleaning performance is significantly greater than the cleaning achieved by a hydroxyamine-free enzyme product in chlorine-free water. This unique performance advantage is not completely understood. It is postulated, however, to be due to the hydroxyfunctionality of the hydroxy-amine participating in the enzyme catalyzed stain-removal reaction.

As an alternative embodiment to preparing a mixture of an enzyme and a hydroxyamine chlorine scavenger of this invention, the benefits of this invention also can be obtained by following a procedure in which an effective amount of a hydroxyamine chlorine scavenger is added to water containing residual chlorine and in another step adding the enzyme composition, e.g., as an enzyme containing detergent composition.

The present invention finds application with all types of enzymes which are inactivated by chlorine in water including proteases, lipases, amylases, carbohydrases, esterases, and many others. A description of the types of enzymes which can be protected by practice of the present invention appears in U.S. Pat; No. 3,451,935, beginning at Column 6, line 1, and extending to C01- umn 9, line 28. This disclosure is incorporated herein by reference. The preferred enzymes for use in practic ing this invention, especially for the detergent composition embodiments, are proteases, lipases and amylases (alpha and beta).

This invention finds special application and provides excellent unexpected improvements in the area of desure is hereby incorporated herein by reference. The

preferred detergents are the anionic class including specifically soap and non-soap anionic detergents such as sodium alkyl benzene sulfonates, the alkyl group being linear or branch and having 10 to 18 carbon atoms, preferably 12 to 16; sodium and potassium alkyl I sulfates, the alkyl group having 10 to 18 carbon atoms,

e.g., sodium coconut and tallow alkyl sulfate, sodium salt of a condensation reaction product of tallow or coconut alcohol with 1 to 20 ethylene oxide groups, preferably 2 to-l2 ethylene oxide groups, such ail-sodium tallow alkylethoxylate averaging three moles of ethyltergency and especially household laundry compositions.

The invention can be practiced by preparing compositions containing only an enzyme preparation and an effective amount of a hydroxyamine as described above. Soiled garments which comprise an ordinary household washing load can be treated, e.g., soaked and/or washedwith such a composition.

A preferred practice is touse such a binary mixture in combination with an organic synthetic detergent to provide a more complete cleaning and laundry compoene oxide per mole of tallow alcohol; sodium olefin sulfonates in which the olefin has 10 to 18 carbon atoms, e.g., sodium dodecene sulfonates, sodium hexadecene sulfonates, and mixtures of the anionic detergents. 7

An unbuilt detergent composition of the present invention comprises from 1 to 99 percent of an organic synthetic detergent, from 1 to 99 percent of an enzyme, and an effective amount of a hydroxyami'ne chlorine scavenger of the type described above. An effective amount can range from 0.001 to 5 percent by weight of the composition, preferably from 0.005 to 2 percent by weight.

For heavy-duty laundering applications, a preferred embodiment of this invention is a detergent composition which comprises from 0.001 to 10 percent of an enzyme, from 0.001 to 5 percent of an hydroxyamine chlorine scavenger of the type described above and from about 1 to 99.998 percent of a mixture of an organic synthetic detergent and a detergency builder salt, the ratio by weight of said detergent to said builder being in the range of 10:1 to 1:20, and preferably from 5:1 to 1:10. Such a composition provides a pH in aqueous solution in therange of 7 to 12; optimum results are obtained in a pH range of 8 1 1.5.

The detergency builder component can be an inorganic or organic alkaline builder of the type described below.

Examples of suitable water-soluble,' inorganic alkaline detergency builder salts are alkali metal carbonates, borates, phosphates, polyphosphates, bicarbonates, silicates and sulfates. Specific examples of suchane-l-hydroxy-l,l-diphosphonic acid, sodium, potassium and lithium salts of methylene diphosphonic acid, sodium, potassium and lithium salts of ethylene diphosphonic acid, and-sodium, potassium and lithium salts of ethane-l,l,2-triph0sphonic acid. Other examples include the alkali metal salts of ethane-2-carboxy-l,ldiphosphonic acid, hydroxymethanediphosphonic acid, carbonyldi-phosphonic acid, ethane-l-hydroxy-1,1,2- triphosphonic acid, ethane-2-hydroxy-1 ,1 ,2- triphosphonic acid, propane-l ,1 ,3,3-tetraphosphonic acid, propane-1,1,2,3-tetraphosphonic acid, and propane-l ,2,2,3-tetraphosphonic acid; water-soluble salts of polycarboxylate polymers and copolymers as described in US. Pat. No. 3,308,067. Specific examples are polymers of itaconic acid, aconitic acid, maleic acid, mesaconic acid, fumaric acid, methylene malonic acid, and citraconic acid and copolymers with themselves and other compatible monomers such as ethylene.

Mixtures of organic and/or inorganic builders described above can be used and are generally desirable. One such mixture of builders is disclosed in US. Pat. No. 3,392,121, e.g., ternary mixtures of sodium tripolyphosphate, sodium nitrilotriacetate and trisodium ethane- 1 -hydroxy-l 1 -diphosphonate.

In these heavy-duty formulations, the detergent can be either a single active detergent or a mixture thereof. Similarly, the builder can be a single builder or a mixture of two or more builders.

The present invention can be effectively used in water having a pH in the range of 4 to 12 depending upon the specific ingredients employed. Builderless systems are effective in slightly acid to neutral soaking and washing systems. The built compositions, however, provide optimum cleaning performance results in an alkali pH range, i.e., 7 to 12 and preferably 8 to 11.5.

The following examples serve to demonstrate the present invention. They illustrate the unexpected performance benefits made possible by using a hydroxyamine chlorine scavenger in combination with an enzyme composition whereby the problem of enzyme deactivation in chlorinated wash water is substantially eliminated.

In the following examples, the enzyme preparation consisted of a mixture of 3.42 percent by weight Bacillus subtilis Carlsburg protease (1.5 Anson units), 2.28% by weight BPN protease (1.5 Anson units). The enzyme preparation also had 7500 a-amylase activity units per gram of said preparation. In the following examples, the enzyme-containing benchmark product was prepared by adding 3.6 parts of the foregoing enzyme preparation to 96.4 parts (all by weight) of the spray-dried benchmark product.

EXAMPLE 1 Cotton muslin swatches (each inches square) stained with licorice, gravy, and spinach were washed in 1.5 gallon automatic miniature washers (AMW) at three temperatures. Previously unwashed stained swatches were used for each temperature. Four washers were employed (AMW Nos. 1, 2, 3, and 4).

The stained muslin swatches were prepared by passing strips of muslin through a padding batch containing a staining solution, passing the muslin through a tworoll wringer and then drying the stained muslin strips. In order to effect deeper stains, the muslin strips were passed through the staining bath a second time followed by drying over night at 120 F. The strip of muslin was then cut into swatches approximately 5% inches square in size.

The wash load in each AMW consisted of three swatches of each different stain plus two 12 inches square unstained (total items), white terrycloths. The terrycloths provide bulk for the wash load and promote more precise stain removal data by providing more even agitation. The even agitation is desired because it minimizes the tendency for the swatches to intertwine, twist, or curl.

A series of washes was conducted demonstrating the invention using F. water, F. water and F. water. These are nominal temperatures. The actual temperatures were slightly lower because the water cooled slightly during the procedures.

The benchmark product used in these demonstrations was a spray dried built detergent composition having the following ingredients by weight:

Weight Sodium linear alkyl benzene sulfonate (alkyl group having an average 13.0 carbons) 12.6 Sodium tripolyphomhate 41.5 Sodium nitrilotriacetate 9.6 Sodium silicate (1.6 R) 7.0 Water 10.0 Sodium sulfate 14.0 E epre nasdescn'bed above .2 Ciifixyme yloellulose .2 Miscellaneous (including brighteners, perfume) Balance to 100% Additional conditions in each washer are given in Automatic miniature washer Table 1 indicates that the conditions which prevailed in AMW No. 1 were no enzyme, no chlorine, and no chlorine scavenger. Essentially this provided results using just the benchmark detergent product shown above.

The conditions in AMW No. 2 differed from AMW No. 1 in the addition to the benchmark detergent product of 0.2 percent of an enzyme ingredient.

The conditions in AMW No. 3 differed from AMW No. 2 in the presence of 1.5 ppm concentration of chlorine in the wash water.

The conditions in AMW No. 4 differed from AMW No. 3 in the addition to the benchmark detergent product of 0.5 parts of a hydroxyamine chlorine scavenger which was tris(hydroxymethyl) amino methane (TRIS).

These varied conditions provided an opportunity to demonstrate the present invention with meaningful comparisons.

The washing procedure consisted of the following steps:

Step 1. The automatic miniature washers (AMW) were filled to their 1.5 gallon capacities with water of the desired washing temperature.

Step 2. The water hardness was adjusted to 7 gr./ga1. by adding 5.5 m1. of a solution which is 7,570 gr./cc. hardness (3 pts. Ca/l pt. Mg. both expressed as CaCO,). Hardness contribution from the load was neglected.

Step 3. The chlorine concentration of each washer was adjusted. To provide for a dmonstration for comparative purposes of 0.0 ppm C1,, 1 ml. of a 0.1N Na,S,O solution was added to the washer. To achieve 1.5 ppm Cl 3.9 ml. ofa chlorine solution (made from adding 3 parts water to 1 part of an aqueous solution containing 0.4% G1,.) was added to the washer.

Step 4. The product being demonstrated was added to the washer, and the water was agitated for two minutes. The product in AMW No. 4 (see Table I above) was made by adding 0.5 parts of 99+ percent pure TRIS chlorine scavenger to 99.5 parts of the above identified benchmark product.

Step 5. After this two-minute agitation, the stain swatches were added. The load was washedfor minutes followed in order by a spin, a rinse, and another spin to damp dry.

Step 6. Each load was tumbled to dryness in a steam dryer operating at 160 F. maximum.

Step 7. Each swatch (except the spinach) was ironed. The spinach swatches were smoothed out by hand.

Step 8. Hunter Whiteness grades were obtained for each swatch for a Hunter Color Difference Meter. This instrument is designed to distinguish color difierences and operates on the tristimulus colorimeter principle wherein the 45 diffuse reflectance of an incident light obtained into a complex formula supplied by the manufacturer. An evaluation of relative whiteness performance compared to a standard detergent composition is thus obtained for the test formulations. These are later compared with other values obtained from other test samples.

A more comprehensive description of this instrument and its mode of operation appears in Color in Business, Science and Industry, by Deane B. Judd, pages 260-262; published by John Wiley & Sons, New York (1952).

The results are shown in Table lLThe product used in AMW No. 1 without enzyme in 0.0 ppm. Cl, serves as the benchmark for measuring the effectiveness of the present invention as illustrated in AMW No. 4. The least significant difference at a=0.05, (LSD is shown for each stain in each treatment in Table 11.

The first column, (AMW No. 2-AMW No. 1), shows the degree of improvement in whiteness cleaning, in terms of Hunter Units, when an enzyme ingredient is used with the benchmark product in 0.0 ppm C1 The second column, AMW No. 3AMW No. 1), illustrates the deterioration in performance when the benchmark product with an enzyme ingredient is used in chlorinated wash water. All A W values less than LSD (column 5) indicate no significant performance advantage for the E-base in chlorinated water. Each of g g 10 hydroxymethyl) aminomethane, referred to at times in this specification as TRIS. It is notable that, in each case, cleaning due to enzyme activityin chlorinated water wasnot only restored but actually increased to levels greater than enzyme cleaning performance in non-chlorinated water. These results indicate that the detergent compositions of this invention are synergetic detergent compositions providing an unexpectedly superior level of cleaning. These synergetic results are obtained even with wash waters having temperatures ranging from cool water to hot water. This is evidenced with the spinach, gravy, and licorice stains demonstrated in Table I].

The AW values are the difference between the first and second washers identified in each column.

Chlorine Level Additives in Wash Water "AMW N0. lzUsed benchmark roduct 0.0% Eben: 0.0% TRIS 0.0

ppm Cl, AMW No. 2:Used benc mark product+0.20% E-hane+0.0%

TRIS 0.0 pm Cl, AMW No. 31Uled benchmark product-+0.20% F.- base+0. TRIS 1.5 ppm Cl, AMW No. 41U|ed benchmark product-+0.20% E-bale+0.5 TRIS 1.5 ppm Cl,

EXAMPLES ll V The procedures described in Example 1 above were repeated with other illustrative aminohydroxy chlorine scavenger compounds at and F. washing temperatures. The aminohydroxy compounds were used at the same level as Example 1 (i.e., 0.5 parts aminohydroxy scavenger added to 99.5 parts benchmark product. The results are shown in Table 111. Here A W values represent the difference in Hunter Whiteness Units between values obtained with the benchmark product with an enzyme and a chlorinescavenger and the benchmark product with an enzyme but without a protective chlorine scavenger (both operating in 1.5 ppm Cl wash water).

The 2-amino-2-methyl-l,3-propanediol (AMPD) and the 2-amino-2-ethyl-l,3-propanediol (AEPD) exhibit comparable chlorine scavenging effectiveness for all three stains at both temperatures, i.e., 75 F. and 125 F. The Z-amino-I-butanol and l-amino-Z- propanol exhibit maximum chlorine scavenging effectiveness at 125 F.

TABLE III Example AW .Example E l IV Example V l Ill Z-aminO- Z-a Z-amino- 1-amino 2-methyl- 2-ethyl- T=75 F. l,-3- 1,3-prw l-butanol 2-propanol propanediol panediol Spinach 5.9 2.4 -0.2 -2.6 Gravy 6.0 4.7 -0.8 1.2 Licorice 1.2 3.8 +0.3 0.5 T=l25 F. Spinach 10.4 14.9 3.7 4.1

Gravy l2.l 13.9 4.3 3.9 Licorice 1.9 4.0 -0.8 0.4

EXAMPLE VI Results similar to those achieved in Example I are obtained when the following hydroxyamine chlorine scavengers are substituted in whole or in part for the TRIS scavenger in Example I: methylamine, lpentylamine, 3-amino-2-propanol, 1-amino-4-hydroxypentane,

2-amino-2-methyll -butanol, 2-amino-l ,3- propanediol; 2-amino-2-hydroxymethyl-l ,6- hexanediol, l-aminol -lethanol, Z-amino-l ,4- hexanediol.

EXAMPLE VII A synergetic detergent composition of the present invention comprises:

Sodium dodecyl benzene sulfonate 20 (dodecyl being linear) Sodium tripolyphosphate 50 Sodium silicate (L6 R) l Sodium sulfate 15 Water 4.4 Alcalase proteolytic enzyme .3

Tris( hydroxymethyl )aminomethane chlorine scavenger This conposition is effective in wash waters containing up to 10 ppm chlorine. When this composition is used under washing conditions in which the molar concentration of chlorine scavenger exceeds that of the residual chlorine an unexpectedly superior stain removal is achieved.

EXAMPLE VIII When the following hydroxyamine compounds are substituted wholly or partially for the TRIS of Example VII, substantially similar results are achieved: Z-amino- 2-methyl-l ,3-propanediol; 2-amino-2-ethyl-l ,3- propanediol; 2-amino-l-butanol; l-amino-2-propanol.

Whereas the preceding examples illustrate the composition embodiments of the present invention, it is to be noted that the hydroxyamine chlorine scavengers can just as effectively be added in an effective amount to the chlorine-containing wash water in a. separate step prior to a washing step.

In this manner, the residual chlorine is reacted with the hydroxyamine chlorine scavenger and is thus not available to attack and deactivate an enzyme ingredient which is added to the water such as an enzymecontaining laundry detergent composition.

EXAMPLE IX Wash wter containing 3.5 ppm residual chlorine and having a temperature of 120 F. is provided. A chlorine scavenger compound which is tris(hydroxymethyl- )aminomethane is added to the wash water in an amount of 6 ppm. This amount corresponds to molar parity between the scavenger and the chlorine. Soiled and stained garments are added to the wash water and laundered therein using the benchmark composition described in Example I. Superior stain removing performance results are obtained as compared to this process in which the chlorine scavenger is omitted.

EXAMPLE X In Example IX, synergetic cleaning results are obtained when the amount of tris(hydroxymethyl) is increased to 12 ppm.

EXAMPLE XI A soaking detergent composition providing synergetic stain removing properties comprises:

Sodium linear dodecyl benzene sulfonate 99% Alcalase protease enzyme .5%

Tris(hydroxymethyl)aminomethane 5% EXAMPLE XII In Example XI, substantially the same results are obwherein each of R R, and R, is selected from the group consisting of hydrogen and alkyl or hydroxyalkyl groups having from I to 6 carbon atoms in an amount sufficient to overcome residual chlorine in the water; and thereafter b. adding to the water an enzyme. g

2. A method according to claim 1 in which the chlorine scavenger is tris(hydroxymethyl)aminomethane.

i i =8 t

Claims (1)

1. 2. A method according to claim 1 in which the chlorine scavenger is tris(hydroxymethyl)aminomethane.