US2454541A - Polymeric detergents - Google Patents

Description

Patented New, 1948 Q 2,454,541 POLYMERIC DETERGENTS Louis B. Bock, Huntingdon Valley, and James L. Bainey, Abingfon, Pa., asslgnors tojtohm & Haas Company, Philadelphia, Pa., a corporatlon of Delaware No Drawing. Application September 9, 1944,

Serial No'. 553,476

- 1' This invention relates to surface-active or capillary-active agents. tion of materials which have high detergent action under a wide variety of conditions. More specifically, it relates to the preparation and use of polymeric, water-soluble detergents which have high molecular weights and contain within each molecule a multiplicity of hydrophobic and hydrophilic groups or portions so arranged and balanced as to become oriented at an interface.

It is generally recognized that surface-active agents, as, for example, alkali-metal soaps or quaternary ammonium compounds, exist in water in the form of micelles. While the exact nature of such micelles is not established, there is evidence that they are electrically charged aggregates of molecules. For example, when a sodium soup of a fatty acid is dispersed in water, it dissociates into positively charged sodium ions and into negatively charged micelles which are aggregates of soap molecules and some negative ions. Because the micelles carry a negative charge, this type of soap is known as an anion-active detergent. In contrast, detergents of the type of quaternary ammonium compounds yield positively charged micelles in aqueous solution and, hence, are known as cation-active soaps or agents. This conception of the formation of micelles is based on measurements of freezing points, vapor pressures, and electrical conductivities of aqueous dispersions of surface-active agents. It is further recognized that surface activity is related to the formation of such micelles and to the orientation of the micelles at an interface.

The individual molecules in colloidal micelles are held together only by physical forces or by weak secondary valences; and, as a result, the extent of micelle formation depends upon the prevailing conditions, and it is affected by such factors as the concentration of the surface-active agent, the presence of electrolytes, solvents, and

6 Claims. (01. zoo-'3) It relates to the prcparato make the use of such detergents uneconomical and often impractical. Furthermore, the materials are ineffective in many laundering operations wherein extremely hot water is used in order to accelerate the removal of soil. 7

The products of this invention differ from-and have advantages overdetergents known heretofore in that their effectiveness is not dependent upon the formation of loosely bound micelles. By the process of this invention, water-soluble macromolecules are synthesized in which all of the bonds between atoms are primary valence links and, hence, are strong and are not affected by such factors as concentration and temperature. Furthermore, the synthesized macromolecules contain balanced hydrophilic and hydrophobic groups so positioned in the macromolecule 'that orientation can and does occur readily at an interface.

The products of this invention may be made rials which are in fact macromolecules and then other surface-active agents, and also upon the temperature. Thus, dilution of the solution, elevation of the temperature, or a change in the amount of any salts which may also be present in solution favor the reversion of micelles into simple molecules and/or ions with the formation of true solutions. As an example, synthetic detergents known heretofore have no value at very low concentrations or in very hot water because under these conditions the micellar structure reverts, the molecules then exist in true solution, and, as a result, detergency is lost. The necessity of using relatively high concentrations plus the higher cost of synthetic detergents combines introducing into said macromolecules hydrophilic groups. The hydrophilic groups, which impart water solubility, may be ether-alcohol groups or esterified ether-alcohol groups and are introduced, for example, by the reaction of ethylene oxide or propylene oxide with the macromolecule. If desired, the terminal hydroxyl of said etheralcohol group may be converted into a, salt-forming ester group of a polybasic acid.

The resultant products may be considered to have three functional portions. Thus, they contain (a) as the hydrophobic portion, the hydrocarbon groups attached to the phenol nucleus; (b) as the hydrophilic portion, the modified or unmodified ether-alcohol groups, and (c) as the polymeric portion, the phenol nuclei joined by methylene bridges. The hydrocarbon groups attached to the phenol and the modified or unmodified ether-alcohol groups also attached to the phenol are so balanced as to assure water solubility and orientation at an interface. At the same time, the polymeric nature of the product assures such a high molecular weight that the product is in fact a macromolecule which imparts capillary.- or surface-activity to a solution, as do micelles of ordinary soaps, but which is stable and is not dissociated as are the micelles of customary detergents under adverse conditions.

The above discussion is for purposes of theoretical explanation only, and it must be understood that the so-called three portions of the macromolecule are not independent of each other 3 but are all combined in one large molecule which functions as a concerted whole.

The type of hydrocarbon group which is attached to the phenol-nucleus may vary as to kind but in every case must contain at least four carbon atoms. In reality, substituting groups of at least eight carbon atoms are much preferred. Generally, it is preferred that the substituent hydrocarbon group be a straight or branched chain acyclic group, such as n-butyl, iso-butyl, tertiary butyl, amyl, tertiary amyl, n-octyl, diiso-butyl, decyl, 'dodecyl, hexadecyl, octadecyl, and the like. Alternatively, phenols substituted with alicyclic groups may be used. These are typified by cyclohexyl phenol, methyl-cyclohexyl phenol, butyl-cyclohexyl phenol. and dicyclchexyl phenol. While aryl-substituted phenols, such as p-phenyl phenol and p-naphthyl phenol, may be employed they are less satisfactory than those listed above unless they in turn contain an alkyl group. Thus, p-tolyl phenol is much preferred though not preferred, it may be in a. form such as a formal or hexamethylene tetramine which will yield formaldehyde under the conditions of reaction.

Ordinarily, the substituted phenol and formaldehyde are reacted by condensing together in the presence of an acidic or alkaline condensation catalyst until the products have become relatively viscous. Solvents may be employed. Acidic condensation catalysts are preferred because of the ease with which the condensation may be controlled. Elevated temperatures naturally accelerate the rate of reaction. Condensation of formaldehyde and substituted phenols such as are here involved do not proceed to the infusible stage and, accordingly, no limit need be imposed upon the degree of condensation. In practice, it is convenient to follow the extent of condensation by means of viscosity measurements and the condensation may be halted at an early stage at which the molecular weight is low and the product on the average has no more than three or four phenolic units per molecule, or it may be continued until each macromolecule contains many more units. The condensation products may range in physical properties from oils to brittle solids, depending upon the degree of condensation and the nature of the substituent hydrocarbon group on the phenol.

Hydrophilic of water-solubilizing groups may be introduced by condensing with the substituted phenol-formaldehyde macromolecule an alkylene oxide such as ethylene oxide, a propylene oxide such as trimethylene oxide or isopropylene oxide, or a butylene oxide such as isobutylene oxide. The condensation is preferably conducted in the presence of an alkaline catalyst such as the hydroxides of the alkali metals, although in some instances no catalyst is required. While the reaction may be carried on at lower temperatures 1 and at atmospheric pressure in the presence of tures above 100 C. under superatmospheric pressure with or without solvents. More than one mol of alkylene oxide is employed and, in fact, it is preferred to use at least eight mols per mol of phenol condensed in macromolecule. The product, which is water soluble and has capillaryaction properties, may be represented by the formula In the formula, R represents a hydrocarbon substituent of four or more carbon atoms, R represents an alkylene group from the class consisting of ethylene, propylene, and butylene groups, p is an integer having a, value of 8 or above and preferably from 10 to 20, inclusive, and a: is an integer greater than 1.

It must be understood that mixtures of the alkylene oxides, such as a mixture of ethylene and propylene oxides, may be employed, although it is preferred to use individual oxides.

Alternatively, detergents having the above general formula may be made from the sodium derivative of the phenol-formaldehyde condensate and a halohydrin of a polyglycol such as CI.(C2H4O)1C2H4OH, BI(C2H4O) mCzI-LOH, or Cl(C3H'1O) QCaH'IOH.

The products are best described as surfaceactive polymeric products containing in their chemical structure hydrocarbon-substituted phenoxy polyalkoxy alcohol units in which units said hydrocarbon substituent contains at least four carbon atoms and said alcohol contains at least eight oxygen-linked alkylene groups from the class consisting of ethylene, propylene, and butylene groups, at least three of said units being joined in each molecule by means of methylene bridges. The product may be esterifled or etherified or otherwise modified to produce detergents of unusual properties. Such modifications are the subjects of other of our applications.

The following examples will serve to illustrate the preferred method of preparing the surfaceactive products of this invention,

Example 1 reflux condenser was charged the following: 412

grams of a,a,y;y-tetramethylbutylphenol, 162 grams of a 37% aqueous solution of formaldehyde, and 27.6 grams of water. The mixture was agitated and heated to a temperature of C. At this point, 246 grams of oxalic acid and 0.92 gram of Twitchell's reagent dissolved in ten grams of water were added. While being agitated, the reaction mixture was refluxed for six hours. Two hundred grams of water and 384 grams of toluene were added, and refluxing was continued for an hour. Agitation was stopped and the contents of the flask were removed to a separatory funnel. The aqueous and resinous layers were separated and the solvent was removed from the resinous layer by vacuum distillation. After the removal of the solvent, heating at a reduced pressure of 1.5 to 2.5 mm. and at a temperature of 245 to 250 C. was continued for four and one-half hours. The condensate then had a viscosity of 4.0 poises when measured as a 60% solution in toluene and, on cooling, solidified to a brittle mass.

Step 2.A mixture of 118 parts of the product of Step 1, having hydroxyl number 01260, two parts of solid Nell, and 100 parts of toluene was heated to 125? to 150 C.in an autoclave. Ethylen'e oxide was added slowly over a period of two and one-half hours until 261 parts of ethylene oxide were absorbed. This corresponds to eleven mols of ethylene oxide per mol of phenol in the product of step 1. The toluene was then removed by steam distillation and the water 'by vacuum distillation at 100 C. The product was obtained as a viscous paste having a-corrected hydroxyl number of 97. It was readily soluble in water and had marked detergent properties. Its formula may be represented by the following:

0(c,H.0)".H o(c=u.o)u.n ILI: CH O 7 on!" J: a can Ezample 2 Step 1.-An octadecyl phenol-formaldehyde condensate was prepared by heating a. mixture of 346v parts (1.0 mol) of octadecylphenol, 81 parts (1.0 mol) of 37% formaldehyde, 18.8 parts of water, 1.23 parts of oxalic acid. and 0.46 partof Twitchell's reagent for seven hours under reflux. One hundred ninety-two parts of toluene and 150 parts of water were added, and refluxing was continued for one-half hour. The aqueous layer was withdrawn and the toluene layer concentrated by removal of toluene under reduced pressure. The residue was finally heated for five 'hours at 250 C. at a pressure of 1.5 mm. of mercury. The product was a soft, viscous material, insoluble in water and having a hydroxyl the use of ethylene oxide, it is understood that a propylene oxide or a butylene' oxide may be employed in a similar manner. In order to impart a given degree of water-solubility, it is advisable to use a greater amount of the higher oxides than the amount of ethylene oxide required.

considerably above twenty to one. In fact, detergents have been prepared in which the ratio was ashighassixty toone. Insuchcasa, the length of the hydrophobic group was also increased in order to assure a balance between the hydrophilic or water-solubilizing portions and the hydrophobic or water-insolubilizing portions.

In the above exampls, the ethylene oxide is slowly added to the heated solution of the phenolic con Altanatively, all of the materialsmaybemixedattheoutsetandthenreacted at an elevated temperature, provided that preca are taken to dissipate the heat evolved during the reaction.

Alloftheproductsofthisinventionfunctlon as capillary-active or surface-active agents. As such, they become oriented at an interface, lower thesurfacetmsionofwater,andcausemore 'rapidwetiangofsurfacessuchasthesurfacesot as measured bythe standard Draves Sinking Test. Their outstanding property is their efiectiveness as detergents. In this capacity, as w H1 by tests and laundering tests, they are oding and are far superior to soaps and synthetic detergents hown heretofore.

As deter-grunts the products described herein maybeusedinhardwaterorinwateroihigh salt content. They may be employed under acidic or i. m tions. Their advantage over syntheidc mts rrsides in the fact that they are not mi but are in fact macromolecules which do not revert as do micella. Thus, they are cut dets at very low concentrations or at very high temperatures where former synthetic detergents failed. They are uncommonly advantageous in the laimdering or cotton fabrics and in the securing of wool, sized, dyed, and printed fabrics in general. 'Iheybeusedforpreparingdispersions-of oil in water or dispersions of polymerizabie materials prior to the polymerization thereof. Aiso,-they serve to break water-in-oil emulsions such as are encountered in oil-fields. And they have been found to be very satisfactory in the trea of leather, in the dispersion of pigments, and as assistants in dyeing.

Theotthisinventicnare particularly useful when used in conjunction with other capillary-active agents, including fatty acid soaps Furthermore, as the entire length of the hydrophilic group is increased, the product ordinarily becomes morewater-soluble. It is, therefore, advisable to increase the hydrophobic group proportionately. This can be done by increasing the size of the hydrocarbon substituent of the phenol, as represented by R in theabove general formula. In this way, a balance is maintained between the hydrophilic and hydrophobic portions of the macromolecule so that the product is water-soluble and at the same time capillary-active, in that it becomes oriented at an interface.

A lowerlimit of eight mols of alkylene oxide per mol of phenol has been indicated above together with a preferred ratio of ten to twmty mols of oxide per mol of phenol. It is to be unand synthetic detergents such as those shown in United States Patents 2,115,192 and 2,143,759. Such combinations have high degrees of wetting and detergent properties.

We claim:

1. Water-soluble, ploymeric detergents formed by by heating (a) one mol of a. phenol having the formula.

hiwhichRisasaturatedhydrocarbonsubstitderstood that the upper limit of the ratio can be 15' uent containing eight to eighteen carbon atoms,

- detergents formed by condensing by heating (a) in which R is a saturated hydrocarbon substituent containing eight to eighteen carbon atoms, and (b) from 0.5 to 1.0 mol of formaldehyde, and then reacting therewith (c). from eig t to sixty mols of ethylene oxide.

4. Water-soluble, polymeric detergents formed by condensing by heating (a) one mol of a phenol having the formula in which R is a saturated hydrocarbon substituent containing eight to eighteen carbon atoms, and (b) from 0.5 to 1.0 mol of formaldehyde, and then reacting therewith (c) from ten to twenty mols of ethylene oxide.

5. Water-soluble, surface-active, polymeric one mol of octyl phenol and (b) from 0.5 to 1.0 mol of formaldehyde and then reacting therewith (c) from 10 to 20 mols of ethylene oxide.

6. Water-soluble, surface-active, polymeric detergents formed by condensing by heating (a) one mol of octadecyl phenol and (b) from 0.5 to 1.0 mol of formaldehyde and then reacting therewith (c) from 10 to 20 mols of ethylene oxide.

. LOUIS H. BOCK.

JAMES L. W.

REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,917,250 Harris July 11, 1933 1,917,257 Harris July 11, 1933 2,046,318 Brubaker July 7, 1936 2,060,410 Balle Nov. 10, 1936 2,076,624 De Groote Apr. 13, 1937 OTHER REFERENCES Clayton-Theory or Emulsions, published by Blakiston 00., Philadelphia, Pa., 4th ed. (1943),

page 127.