US3007876A - Solid organic bleach compositions - Google Patents

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3,667,876 Patented Nov. 7, 1961 3,007,876 SOLID ORGANIC BLEACH COMPOSITIONS John R. Schaelfer, Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Nov. 21, 1957, Ser. No. 697,793 7 Claims. (Cl. 252-99) This invention relates to a solid organic chlorinated bleaching and oxidizing agent. The invention comprises a new class of compounds, N,N'-dichlorobenzoyleneureas.

Bleaching materials in powdered form are very de- They can be used alone to make an active bleaching solution or, more commonly, they can be used with powdered or granular detergents or cleansers, becoming active when used with water. A suitable powdered bleach should have strong bleaching power, good stability, and reasonable compatibility with detergents or other materials with which it is to be associated, and should not have an objectionable odor. Nearly all of the common powdered chlorinated bleaches are deficient in one or more of these properties, although chlorinated powdered bleaches which hydrolyze to form hypochlorous acid, a strong bleaching and oxidizing agent, are usually considered the most satisfactory.

Common inorganic powdered bleaches include sodium perborate which is low in practical bleaching capacity and calcium hypochlorite which furnishes calcium ions that increase water hardness. In an attempt to find a suitable powdered bleach, many chlorinated organic compounds have been developed. Generally, those chlorinated organic compounds such as N-chloramines which have a high percentage of available chlorine, a term hereinafter defined, are undesirably odoriferous, e.g. some have a nauseating lachrymatory odor, are unstable, or are incompatible with materials with which they may be associated. Those chlorinated organic compounds which do not have undesirable odors, which are stable or which are compatible with detergents usually have low bleaching activity or have a low percentage of available chlorine.

It was therefore, desirable to find a chlorinated organic compound that would have a high percentage of available chlorine and have a high degree of stability and which would also have little odor and would be relatively compatible with the usual detergents.

The term percent available chlorine is used to indi cate the oxidizing capacity of a chlorine containing compound. It is that weight of elemental chlorine (C1 that would exert the same oxidizing action as 100 parts of the chlorine compound in question.

N-chloramines, which include chloramines, chloramides, chlorimines and chlorimides are discussed in volume 3 f the Kirk-Othmer Encyclopedia of Chemical Technology, pages 664-676. In producing N-chloramines the hydrogen in an =NH group is replaced with chlorine by chlorination. When the N-chloramines are combined with water, i.e. hydrolyzed, hypochlorous acid is apparently formed from the available chlorine in the compound and the original amine, amide, imine or imide is formed when hydrogen from the water replaces the chloline as shown in the following general equation:

Alkaline conditions appear to increase the amount of hypochlorous acid or hypochlorite ions resulting from the hydrolysis of the N-chloramines. Hypochlorous acid and hypochlorite ions are believed to be the source of the bleaching activity of N-chloramines.

Knowledge of a particular nitrogen-containing organic compound is not alone sufiicient basis for an accurate prediction of the ability of the compound to undergo successful chlorination or of the stability of the ensuing compound should one result. In general N-chloramines are unstable, losing most of the available chlorine which they contain within a very short time. Moreover, the bleaching effectiveness of an N-chloro organic compound cannot be predicted, even if itis stable.

It is the object of this invention to provide a chlorinated organic compound that has a high percentage of available chlorine, that has a high degree of stability, that is substantially free of unpleasant odor and that is relatively compatible with synthetic detergents.

It has been found that this object is realized in providing a new class of organic compounds, N,N'dichloro benzoyleneureas; this class includes 1,3-dichloro-tetrahydroquinazoline-2,4-dione, any of its tautomeric forms and the simple derivatives thereof.

The N,N'dichlorobenzoyleneureas of this invention were found quite unexpectedly to be highly satisfactory stable bleaching agents with little odor since N-monochlorobenzoyleneurea is not stable. The N,N'dichlorobenzoyleneureas of this invention can be produced by chlorinating benzoyleneurea or its simple derivatives. Benzoyleneurea (tetrahydroquinazoline-2,4-dione) is a known compound which can be produced in a number of ways, several of which are described in volume 6 of Elderfield, Heterocyclic Compounds, pages 339-40. Benzoyleneurea has the following structural formula:

A compound of this invention, 1,3-dichloro-tetrahydroquinazoline-2,4-dione, can be obtained, for example, by replacing the hydrogen atoms attached to the nitrogen atoms of the heterocyclic ring with chlorine atoms.

Simple derivatives of 1,3 -dichloro-tetrahydroquinazoline-2,4-dione function as stable effective bleaching agents in substantially the same manner as the parent compound. Simple derivatives are those compounds in which hydrogen atoms are substituted in the carbocyclic ring with monovalent radicals which do not affect the active chlorine atoms in the heterocyclic ring. Such radicals are chloro, bromo, iodo, ethyl and methyl and can substitute hydrogen atoms in the 5, 6, 7 and 8 positions in the carbocyclic ring. The general structure of 1,3 dichloro tetrahydroquinazoline 2,4 dione and its simple derivatives is ino where X X X and X can each be hydrogen, chlorine, bromine, iodine, ethyl or methyl. Examples of simple derivatives are 1,3,6-trichloro-tetrahydroquinazoline-2,4- dione (where only the chlorine in the 1 and 3 positions can constitute available chlorine), 8-ethyl-1,3-dichlor0- tetrahydroquinazoline 2,4 dione, 6 bromo 1, 3-

dichloro tetrahydroquinazoline 2,4 dione, 6 iodor 1,3 dichloro tetrahydroquinazoline 2,4 dione and 8 methyl l, 3 dichloro tetrahydroquinazoline 2,4- dione. Where only one X is a halogen atom or lower alkyl radical, the remainder of the Xs being hydrogen, the above structural formula may be written X having the same significance as before.

Example The preferred method for producing 1,3-dichloro-tetrahydroquinazoline-2,4-dione involves introducing about four-moles of chlorine gas into an aqueous suspension of about one mole of benzoyleneurea and about 2.5 moles of sodium carbonate at a temperature of about C. The product is then recovered by filtering the reaction mixture, washing the filtrate three times with ice water and drying the product over phosphorous pentoxide. It has been observed that the chlorine gas should be added rapidly in order to ensure that the mole ratio of chlorine p to benzoyleneurea' is about 4:1. This much excess chlorine is necessary to prevent hydrolysis of the compound in the alkaline solution. If about three moles of chlorine is used the reaction product apparently has less stability.

It has been found that the most stable product can be obtained by recrystallizing the product from chloroform. To do this, the product is dissolved in chloroform, the insoluble material is filtered OE and the dissolved 1,3 dichloro tetrahydroquinazoline 2,4 dione is m cipitated by adding petroleum ether.

When the simple derivatives of benzoyleneurea, such 2 as 8 -methyl-tetrahydroquinazoline-2,4-dione and 6-chlorotetrahydroquinazoline-2,4-dione are substituted for the benzoyleneurea mole for mole in the chlorination process described in the preceding example, the corresponding simple derivatives of 1,3-dichloro-tetrahydroquinazoline- 2,4-dione are produced.

It has been found that 1,3-dichloro-tetrahydroquin azoline-2,4-dione, after recrystallization, has about 60% available chlorine and will lose only about 6% of this available chlorine when the compoundis stored in a thin layer (about ,4 inch) for 10 days at 12 0 F. and 50% relative humidity.

V 4 sulfated fatty alcohol .(sodium salt) which was derived from 'the reduction of tallow and sodium polypropylene benzene sulfonate the polypropylene radical averaging about 12 carbons, 8% moisture, 6% sodium 7 V silicate and the remainder consisting of smallamounts of sodium carboxymethylcellulose, perfume, fluorescent brightening agents, lauryl alcohol and coconut oil fatty acid ethanolamide. The bleach was present in an amount equivalent to 2.6% initial available chlorine by weight of the sample in each case. The samples were stored in a layer /2 inch thick at 80 'F. for one month.

" The'N,N'dichlorobenzoyleneurea compounds ofthis invention when used to bleach fabrics do not cause pinholing, acommon fault of most other solidchlorinated bleaches. Pinholing is the destruction of a very small area o f fabric due to high localized concentration of oxidizing agent. Even though the N,Ndichlorobenzoyleneureas are very effective bleaches and are only slightly soluble, they do not have this fault even when used with cotton fabrics which are particularly susceptible to am age under the conditions .described.

The bleaching capacity of chlorinated compounds, particularly the N,N'dichlorobenzoyleneiireas of'this invention, is measured by their ability to oxidize the stains commonly found in soiled fabrics and other materials to colorless products. his well known'that while'dirt'can be washed away by detergents, stains require'the chemical action of oxidizing bleaches.

The followingtable of tests illustrates widely used chlorinated bleach, Halane.

The N,N'dichlorobenzoyleneureasof this invention are I believed to hydrolyze, especially in an alkaline solution,

to yield the amide and free hypochlorous acid orhypochlorite ions which have been reported to be the prob able source of bleaching activity. Benzoyleneurea or its simple derivatives which are apparently formed from this hydrolysis are inocuous and can be washed away after the bleaching operation.

The 'N,N'dichlorobenzoyleneureas are only slightly soluble in water, but it has been found that this'does not impair their high bleaching capacity as they are effectively dispersed in water. These compounds have a very slight chlorine odor which is inoifensive. They have ben observed to be compatible with detergent compositions.

in that the ingredients commonly found in anionic detergent formulations do not react to cause decomposition of the N,N'dichlorobenzoyleneurea compound to an undesirable degree as compared'to other chlorinated -organic compounds.

This compatibility is illustrated in the following table in which diflerent organic bleaches are compared. .The samples contained a portion of bleach and the remainder a typical heavy duty detergent composition containing about 50% sodium tripoly-phosphate, 15% sodium sulfate, 17.5% synthetic detergent consisting of about 50% nesium oxide as 100% reflectance was used as standard.

The tests consisted of washing a piece of stained cloth in a Launderometer. The Launderometer and its use are described in Schwartz and Perry, Surface Active Agents (1949),

pages 3 54-56, and in the Yearbook of the American Association of Textile Chemists and Colorists (1944), page '149. A piece of 'cloth,'the washing solution and 10. glass balls were placed in' each Launderometer 'jar and sealed. Twenty such jars were then placed in the Launderometer and rotated end for end at about 60 revolutionsper minute for,10 minutes in a water bath at 140 F. The washing solutions contained about 0.3% sodium orthophosphate and" about 0.06%

sodium polypropylene benzene sulfonate, the polypropylene radical averaging about'l2 carbons- The solutions had bleach compound concentrations. equivalent to and 200 parts per million of available chlorine. The solution was at a pH of 9.0; The pieces of cloth were rinsed thoroughly'in distilled water after washing and dried in thedark. T he reflectance of the dried pieces of cloth was measured in a Lumetron colorimeter Model 402E (PhotovoltCorpJ using a filter which passes light of the wavelength of an absorption maximum of the stain. An enamel plate standardized in terms of mag- ,The figures ,in the table are reflectance values, a white cloth having a value of;70. *For each stain the figures in the left column are for a bleach compound concentration equivalent to 100 parts per million of available the eifectiveness of the bleaching action of a compound of this invention on various stains compared to the bleaching action of a chlorine and the right column, 200 parts per million of available chlorine.

An N,N' dichlorobenzoyleneurea when compared in a manner similar to the tests described above, with other chlorine containing bleaches such as sodium hypochlorite and trichloroammelide on stains such as mercurochrome, chlorophyll, tea and morin, showed a broad spectrum of effectiveness.

What is claimed is:

1. The process of making 1,3-dichloro-tetrahydroquinazoline-2,4-dione comprising the steps of introducing about 4 moles of chlorine gas into an aqueous suspension of about one mole of benzoyleneurea and about 2.5 moles of sodium carbonate, filtering the reaction mixture, washing the filtrate with ice water and drying the filtrate.

2. The process of making 1,3-dichlorotetrahydroquinazoline-2,4-dione, comprising the steps of introducing about 4 moles of chlorine gas into an aqueous suspension of about one mole of benzoyleneurea and about 2.5 moles of sodium carbonate, filtering the reaction mixture, washing the filtrate with ice water, drying the filtrate and recrystallizing the resulting product from chloroform by dissolving the product in chloroform, separating the insoluble material and precipitating the product with petroleum ether.

3. A dry bleach composition characterized by a high degree of bleaching effectiveness, stability and compatibility comprising as its essential bleaching ingredient a N,N'dichlorobenzoyleneurea compound which has the structure X3 IO] X6 N-Cl where X X X and X are each a radical selected from the group consisting of hydrogen, chlorine, bromine, iodine, ethyl and methyl, and an inorganic water soluble alkaline agent said bleaching ingredient being present in suflicient amount to provide bleaching activity and said alkaline agent being present in sufficient amount to provide an alkaline solution when said composition is dispersed in water.

4. The composition of claim 3 wherein all the Xs in the N,Ndichlorobenzoyleneurea compound are hydrogen and which includes a synthetic detergent.

5. The composition of claim 4 wherein the inorganic alkaline agent includes sodium tripolyphosphate and the synthetic detergent is selected from the group consisting of sulfated fatty alcohols and alkyl benzene sulfonates.

6. The process of bleaching fabric which comprises the step of exposing the fabric in an aqueous medium to a N,N'dichlorobenzoyleneurea compound which has the structure References Cited in the file of this patent UNITED STATES PATENTS Baker et al. Dec. 9, 1952 Blomfield May 31, 1960 OTHER REFERENCES Scott et al.: Iour. Chem. Soc., vol. 119, pages 664- 672 (1921).

Whitmore: Organic Chemistry, page 783, second edition (1951).

Claims (1)

1. 3. A DRY BLEACH COMPOSITION CHARACTERIZED BY A HIGH DEGREE OF BLEACHING EFFECTIVENESS, STABILITY AND COMPATIBILITY COMPRISING AS ITS ESSENTIAL BLEACHING INGREDIENT A N,N''DICHLOROBENZOYLENEUREA COMPOUND WHICH HAS THE STRUCTURE