US 3167513 A
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United States Patent Ofiice 3,l57,5l3 Patented Jan. 26, 1965 3,167,513 BLEACHING Cfih EQSITIONS Jan Cirirsena Meerkamp van Ernhrien and Jan Boldingh, Viaardingen, Netherlands, assignors to Lever Brothers Company, New York, N.Y., a corporation of Maine No Drawing. Fiied Mar. d, 1959, Ser. No. 797,053 Claims priority, application Great Britain Mar. 7, 1958 7 Claims. (Cl. 252-1ti2) This invention relates to bleaching compositions, and in particular to detergent bleaching compositions.
Many bleaching compositions, especially detergent bleaching compositions, contain inorganic per-compounds such as sodium perborate or percarbonate. These percompounds provide a satisfactory bleach when the composition is used at the boil, but at lower temperatures their action is too slow to be really effective within the normal bleaching time. Moreover, the amount of oxygen used actually in bleaching is rather low in comparison with the total amount of available oxygen.
It is an object of the present invention to provide a more effective bleach than can be obtained with an inorganic per-compound, such as sodium perborate, at both low and higher temperatures.
It has been previously proposed to use bleaching compositions containing an organic per-carboxylic acid, such as for example peracetic acid. Owing to the instability of such compounds, particularly in alkaline conditions such as occur normally in detergent compositions, it has, however, been necessary to prepare them only shortly before use. On account of this, it has not been possible to use them commercially, since bleaching compositions are generally used some time after manufacture, especially when they are intended for use in the home.
It has now been found that organic per-carboxylic acids derived from monoor di-carboxylic acids, and their derivatives such as the acyl peroxides, can be made into excellent stable bleaching compositions by combining them with urea to form adducts or so-called inclusion compounds.
It is, of course, well known, that urea forms inclusion compounds with various organic compounds, such as aliphatic hydrocarbons, alcohols, aldehydes, ketones and acids. It was, however not known that urea also exhibits this property with organic per-carboxylic acids and acyl V peroxides.
It has, moreover, been found that the organic perin inclusion compounds with urea become stabilised to such an extent that they can be used a long time after their preparation. In particular, the per-acids and acyl peroxides derived from dicarboxylic acids are not affected by other ingredients normally used in bleaching and detergent compositions.
The present invention, therefore, provides an inclusion compound of urea and a per-derivative of a straight-chain aliphatic carboxylic acid.
It also provides a bleaching composition containing such an inclusion compound.
Inclusion compounds in accordance with the present invention may be formed by organic alpha-monopercarboxylic acids containing at least 4 carbon atoms in the molecule and by organic per-alpha: omega-dicarboxylic acids containing at least carbon atoms in the molecule. Per-acids containing up to 20 carbon atoms in the molecule may be used; per-monocarboxylic acids containing from 6 to 10 carbon atoms and per-dicarboxylic acids containing from 10 to 14 carbon atoms are preferred. Per-acids of this type may be derived from saturated aliphatic monoor dicarboxylic acids and include, for instance per-butyric acid, per-valeric acid, per caproic acid, per-heptanoic acid, per-caprylic acid, perpelargonic acid, per-capric acid, per-undecanoic acid, per-lauric acid, per-myristic acid, per-palmitic acid, perstearic acid, monoand di-per-sebacic acids and monoand di-per-brassylic acids. Per-acids containing substituents such as, for example, methyl, hydroxy, or keto groups and those containing double bonds may also be used.
Inclusion compounds according to the invention may also be formed by acyl peroxides derived from aliphatic monoor dicarboxylic acids, in particular from the acids quoted above. In mixed acyl peroxides, however, one of the groups may be derived from an aliphatic monoor dicarboxylic acid having a shorter carbon chain than these acids. The acyl peroxides have the general formulae:
(4) R.C0.0.0.CO.R".C0.0.0.CO.R' (5) R.C0.0.0.CO.R".C0.0.CO.R'
in which R and R are aliphatic hydrocarbon groups containing from 1 to 19 carbon atoms in a straight chain and R" is a divalent hydrocarbon group containing from 1 to 18 carbon atoms in a straight chain, with the restriction that either R or R contains at least 3 carbon atoms in a straight chain or R" contains at least 8 carbon atoms in a straight chain. R, R, and R may each be substituted and may contain the same or different numbers of carbon atoms.
Mixtures of peracids and acyl peroxides and mixtures of these substances with unconverted monoor dicarboxylic acids or their anhydrides may also be used.
The method of preparation of the per-acids and acyl peroxides is not a feature of the invention. Two useful methods of preparing the per-acids are illustrated, however, in the examples, while the acyl peroxides may, for example, be prepared by the reaction of a per-acid with an acid illustrated by the following equation:
The acyl peroxides are often formed in subsidiary amounts in the preparation of the per-acids.
The inclusion compounds according to the invention may be prepared by treating the per-derivatives with urea in any known way for preparing inclusion compounds, for example by mixing them with the urea dissolved in a solvent such as methanol and isolating the product by crystallisation or evaporation. The products so obtained are crystalline substances having the usual structure of inclusion compounds of urea.
All the products of the invention are very stable, but particularly stable products are obtained if a smallamount of sulphuric acid, preferably (LS-3% by weight of the per-derivative, is added during the preparation of the inclusion compound. They do not explode or ignite when heated or subjected to shock and they do not lose oxygen to any appreciable extent when kept at room temperature. They may frequently be mixed with other substances without losing their stability. Their stability is, however, diminished by the presence of alkaline compounds. This diminution is less with per-derivatives of dicarboxylic acids than with per-derivatives of monocarboxylic acids and, in particular, the inclusion compounds derived from per-derivatives of di-carboxylic acids are very stable in the presence of the usual ingredients of detergent compositions. When brought into contact with water they dissolve easily and the resulting solutions have excellent bleaching properties both at low and high temperatures, exceeding those of perborate solutions containing the same amount of active oxygen. In addiion, such solutions show a much better oxygen efficiency than perborate solutions, i.e. the amount of oxygen used actually in bleaching in Comparison with the total amount of available oxygen is much higher than with perborate solutions. It is, therefore, easier to appl the exact amount needed for the bleaching operation envisaged and this results in greater economy in the application of the products of the invention. The products of the invention are, moreover, strongly bactericidal, for example against Escherichia coli and Staphylococcus aureus. 3
When products according to the invention are used in detergent compositions, these may contain either soap or organic soapless detergents such as, for example, alkylaryl sulphonates, alkyl sulphates, fatty monoglyceride sulphates, salts of amides of taurine or methyltaurine, and salts of esters or ethers of isethionic acid. They may also contain alkali-metal carbonates, silicates, sulphates, and phosphates, such as orthophosphates, pyrophosphates, polyphosphates and metaphosphates, and other conventional ingredients of detergent compositions such as carboxy-methylcellulose, lather improvcrs, fluorescent brightening agents, anti-tarnishing agents, perfumes and the like. Inorganic per-compounds such as perborates and percarbonates may also be present. They may be in any solid form, such as powders, chips, flakes, bars or tablets.
The amount of inclusion compound to be incorporated in a bleaching composition depends on various factors such as the bleaching effect required and the nature and concentration of the per-acid in the inclusion compound. Bleaching compositions have been found particularly useful in which the amount of inclusion compound corresponds to from 0.05 to preferably from 0.3 to 1.5%, by weight of the total composition, of active oxygen.
The invention will now be illustrated by the following examples:
EXAMPLE 1 (a) 50 g. (0.8 mol) of boric acid were mixed with 250 g. (2.45 mols) of acetic acid anhydride and heated to 90 C. During the reaction the temperature increased to 120 C. owing to the heat of reaction evolved. On cooling the reaction mixture, pyroboric acetate was obtained in a yield of 92% calculated on the amount of boric acid used.
(b) 15.2 g. (0.05 mol) of pyroboric acetate and 28.8 g. (0.2 mol) of caprylic acid were mixed with 60 ml. of xylene and heated on a water bath to about 90 C. until a clear solution was obtained. The xylene and the acetic acid formed during the reaction were then distilled ofi at a temperature of 3040 C. under a vacuum'of mm. Hg. The residue was a crystalinesolid consisting of pyroboric caprylate, obtained in a yield of 99% calculated on the pyroboric acetate used.
(c) 12.5 g. (0.02 mol) of pyroboric caprylate were added in about 15 minutes to 0.08 mol of hydrogen peroxide dissolved in ether at 10 C. The reaction mixture was kept at room temperature (about C.) for one hour and the boric acid formed was filtered off. The filtrate was Washed with water and dried over sodium sulphate and the ether was distilled off at about 20 C. under a vacuum of 15 mm. Hg. The residue consisted of a mixture of per-caprylic acid (about 68%), dicapryl peroxide (about caprylic acid (about 4%) and boric acid (about 3%) obtained in a yield of 65% of per-compounds calculated on the pyroboric caprylate used. It is a rather unstable liquid which normally loses practically all its active oxygen at room temperature in about 8 days.
(d) 10 g. of this residue were added at room temperature about 20 C.) to 50 g. of urea dissolved in 250 ml. of methanol.
The mixture was then cooled to -10 C. and the contaminated urea which precipitated was filtered oil. The
filtrate was freed from methanol by evaporation at 40 C. under a vacuum of 15 mm. Hg. The residue (29.5 g.) consisted mainly of the urea inclusion compounds or percaprylic acid and dicapryl peroxide. It contained about 18% by weight of the per-compounds. It was very stable; on keeping some at room temperature for 7 days no loss of active oxygen could be detected.
(e) The crude percaprylic acid mixture obtained according to (c) was'fractionated under a vacuum of 15' mm. Hg. In this way practically pure dicapryl peroxide was obtained. The dicapryl peroxide is a fairly stable crystalline solid, losing about 18% of its active oxygen at room temperature in 8 days. It can be converted into the urea inclusion compound by theprocess given under (d).
EXAMPLE 2 (a) To 39.8 g. (0.2 mol) of lauric acid dissolved in 61.2 g. (0.6 mol) of sulphuric acid (96%) were gradually added 20.5 g. (0.3 mol) of a 50% hydrogen peroxide solution at 10 C. with constant stirring. After the addition, stirring was continued for 3 hours at 15 C. The suspension thus obtained was diluted with ice-water, which caused the per-acid to precipitate. The precipitate was filtered off, Washed four times with ice-water and dried in a vacuum desiccator. 39.1 g. of dry crystalline product containing 89% of per-lauric acid were obtained (yield 81%).
(b) 6 g. of per-lauric acid as obtained under (a) and 18 g. of urea were dissolved in 100 ml. of methanol. The solution was heated on a water bath and the solvent was evaporated under vacuum. 23.9 g. of pure inclusion compound containing 23% of per-lauric acid were obtained.
EXAMPLE 3 (a) To 20.2 g. (0.1 mole) of sebacic acid dissolved in 140 g. (1.2 moles) of sulphuric acid (85%) were gradually added 34 g. (0.3 mol) of a 30% hydrogen peroxide solution at 10 C. with constant stirring. After the addition, stirring was continued for 2 hours at 20 C. The per-acid precipitated in small crystals and was filtered off, washed four times with ice-water and dried in a vacuum desiccator. 21.5 g. of di-persebacic acid of 96% purity were obtained (yield 88%).
(b) 2.4 g. of urea were mixed with 0.7 g. of di-persebacic acid as obtained under (a). The mixture was heated to 65 C. with vigorous stirring. Without further heating the temperature rose to 70 C. After stirring for another 30 minutes, the reaction mass was cooled to room temperature. 3.1 g. of urea adduct precipitated, containing 19.3% (calculated: 19.7%) of di-per-sebacic acid. The adduct was not a pure inclusion compound, and contained free di-per-sebacic acid and tetragonal urea together with the hexagonal urea-inclusion compound.
EXAMPLE 4 (a) To 23.4 g. (0.096 mol) of brassylic acid dissolved in 140 g. (1.2 moles) of sulphuric acid (85%) were gradually added 20.4 g. (0.3 mol) of a 50% hydrogen peroxide solution at 10-15 C. with constant stirring. After the addition, stirring was continued for 6 hours at 20 C. The per-acid precipitated in small crystals and was filtered off, washed four times with ice-water and dried in a vacuum desiccator.
Thus 26.5 g. of di-per-brassylic acid of 92% purity were obtained (yield 92% (b) 41 g. of urea and 10 g. of di-per-brassylic acid as obtained under (a) were dissolved in 200 ml. of methanol. The solution was heated to 50 C. and subsequently cooled to -17 C. The crystalline precipitate formed was filtered off and dricdin a vacuum desiccator. The product thus obtained was the pure inclusion compound containing 23.8% di-per-brassylic acid (yield 33 g., i.e. 90
EXAMPLE Three detergent compositions were prepared from the following ingredients:
Three solutions were made, each containing 5.4 g. of the above-mentioned detergent composition dissolved in 1 l. of water (14 German hardness). To these solutions were added sodium perborate, the inclusion compound of di-per-sebacic acid as prepared in Example 3 and the inclusion compound of di-per-brassylic acid as prepared in Example 4, respectively, in amounts corresponding to 60 mg. of active oxygen per litre.
Pieces of cotton stained with tea were washed in these solutions at different temperatures and for different times. The cotton to washing liquid ratio was 1:20. The table below shows the results, expressed as increase in percent reflection measured with an Elrepho reflectometer.
1. A bleaching composition which contains an inclusion compound of urea and a per-derivative of a straightchain aliphatic alpha-monocarboxylic acid containing 4 to 20 carbon atoms in an amount sufiicient to impart eifective bleaching properties to the composition.
2. A bleaching composition which contains an inclusion compound of urea and per-caprylic acid in an amount sufficient to impart effective bleaching properties to the composition.
3. A bleaching composition which contains an inclusion compound of urea and per-lauric acid in an amount sufficient to impart effective bleaching properties to the composition.
4. A bleaching composition which contains an inclusion compound of urea and a per-derivative of a straightchain aliphatic alpha:omega-dicarboxylic acid containing 10 to 20 carbon atoms in an amount sufficient to impart effective bleaching properties to the composition.
5. A bleaching composition which contains an inclusion compound of urea and di-per-sebacic acid in an amount sufiicient to impart effective bleaching properties to the composition.
6. A bleaching composition which contains an inclusion compound of urea and di-per-brassylic acid in an amount sufficient to impart effective bleaching properties to the composition.
7. A bleaching composition which contains as a bleaching agent an inclusion compound of urea and di-perbrassylic acid in an amount corresponding to 0.05-10%, by weight of the total composition, of active oxygen.
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