FOSTER DEE SNELL
I/EC
Foster D. Snell, Inc., 2 9 W e s t 1 5th St., New York, Ν. Υ.
ANNUAL
REVIEW
SOAP AND SYNDETS E is
ITHER the A m e r i c a n
population
becoming more cleanlinessminded or it is building u p a stock pile in the home. T h e estimated total production of soap a n d syndets for 1956—extrapolated from the first 6-months' figures—is u p radically. I n contrast to 1955, when the increase in syndet sales was at the expense of soap sales, this year syndet sales in creased 2 5 % in tonnage a n d 1 9 % in dollar volume in t h e first 6 months of 1956, with no corresponding d e crease in soap sales. T h e chart on page 52 A includes both solid a n d liquid forms of each. Soap appears to have hit a level which will not be reduced by m u c h until the syndet b a r begins to en croach seriously on the toilet b a r market or until substantial amounts of syndets replace soap in t h e power laundry. T h e first of these might be imminent. It is 3 8 % of the tonnage and 5 0 % of the dollar value in the remaining soap market. T h e second can only take place slowly a n d to a degree not yet predictable. Syndets on the other hand a p p e a r to have found new fields to conquer and are 6 8 . 6 % of the total deter gent market as compared with 6 3 . 2 % last year. Surfactants
W h e n syndets entered the Ameri can market as a volume item, as distinguished from a minor specialty, they drew on a n already existing surfactant market for their active agent. Of course, this has increased the total surfactant production of which syndets have taken an increas ing percentage, currently stabilized around approximately 5 0 % . T h e following table (millions of pounds) 50 A
with some extrapolations, illustrates the point. T h e surfactants do not include sulfated (sulfonated) oils. However, in the past 8 years the total surfactant market was multi plied by 3 while that for syndets was multiplied by 7. P u t in another way, the surfactants not used in syn dets but little more than doubled. A recent survey classified t h e surfactants as 25 types distributed over 75 applications, less t h a n a third of them of a minor nature. While the majority were for cleaning of some type, 182 million pounds were used as lubricant additive, a n d 75 million pounds for foaming of con crete. M o r e conventional is 10 million pounds for washing cars. Soap
R a w materials have remained stable, tallow at 7 to 8 cents a pound, crude coconut oil a t 12 cents a pound. T h e figures arc charac teristic of materials in excess supply. In J u l y , A r m o u r discontinued m a n u facture of soap a n d glycerol at North Bergen, N . J . T h e Swedish Centripur method with special separators is reported to reduce the time for soap manufac ture to 1 hour. T h e r e is further increase in the popularity of deodor ant a n d germicidal soaps a n d two new germicides for the purpose were
INDUSTRIAL AND ENGINEERING CHEMISTRY
Surfactant Production
Year 1949 1951 1953 1955
Total Surfactants 430 680 920 1150
Surfactants in Syndets 180 380 470 575
% Surfactants in Syndets 42 56 51 50
patented : 2,2 '-ethylidenebis(4chloro-6-nitrophenol) a n d 4-chloroa,a' - bis - (2 - hydroxy - 3 - chloro5-methylphenyl) -2,6-xylenol. Practical washing tests have demonstrated that soap is a more efficient detergent than some of the syndets in soft water. Nevertheless definite inroads have been m a d e in the commercial laundry field. This 100-million-pound market has so far lost less than 5 % of its volume to syn dets, largely to fatty alcohol sulfates. Anionics
Volumewise sodium dodecylbenzene sulfonate is close to 5 0 % of the 1000 million pounds per year of surfactants being produced cur rently. Its percentage of the market is slowly receding. Continuous sulfonation has been extended to the use of 2 0 % oleum in scraped film equipment to give rapid reaction a n d low discoloration. A plant under construction in C a n a d a will provide its alkylate requirements, using pro pylene tetramer. Another will sul fonate it. Previously syndet im ports from the United States, partly as slurry, have been valued at about 2.5 million dollars. T r e a t m e n t of the product with a l u m i n u m chloride is reported to give a pure white alkylaryl sulfonate. Addition of sodium silicate to the hypochlorite used for bleaching the alkylaryl sulfonic acid gives im proved bleaching. O n e of the large sulfonators is promoting sale of alkylaryl sulfonic acid in drums to be mixed in the batch with builders a n d neutralizing agents, giving a homo geneous product. Reduction of cak ing a n d lumping ofStheend product is facilitated by addition of the sodium
Three steps in pilot plant production of the new sucrose fatty acid detergent, which w i l l be available commercially in 1957
3.DRYING
2. PURIFICATION
1. ALCOHOIYSIS salt of methyl, ethyl, or isopropyl sulfate. Stability and volume of the foam of alkylaryl sulfonates are improved by addition of JV-olcyl-iV-methyl taurate. A competitor for the functions of C M C in syndets is partially acylated poly (vinyl alcohol). Test marketing of a bleach cleanser for hard surfaces has been successful to a degree justifying the offering in a larger area. T h e claims for the new product include effectiveness as a germicide, thus adding a plus value to bleach cleansers. T h e familiar precipitation of anionic agents by cationic agents is avoided when the latter is an iodine complex of dodccylbenzyldiethyl cthanol quaternary ammonium chloride. T h e combination sanitizes as well as washes dishes. Dichlorodimethylhydantoin has been successfully incorporated as a bleaching agent in a spray-dried anionic. A 0 . 1 % solution of alkylaryl sulfonate removes 90 to 9 5 % of insects and larvae in berry washing. It has long been known that detcrgency is improved by minimum branching of the side chain of alkylaryl sulfonates, this being the reason for use of tetrapropylene rather than tributylene. With a straight side
chain the maximum foaming is at a chain length of 10 to 12 carbons. T h e detergency, however, increases up to a side chain of 18 carbons. Coke-oven benzene is now purified to meet the standards set by synthetic benzene. T h e 1956 production of syndets can be expected to consume over a billion pounds of molecularly dehydrated phosphates. Newer Anionics
T h e cost of more complex structures must be balanced against greater efficiency in going from sodium fatty alcohol sulfates. Sodium lauryl ether sulfate gives clear solutions in very hard water and has a cloud point 20° lower than sodium lauryl sulfate. The high foaming power makes it appropriate for some of the higher cost products such as shampoos, rug cleaners, even dishwashing. Introduction of 2 to 4 moles of ethylene oxide between the dodecyl group and the sulfate group is desirable. Then a 3 0 % solution is clear and the product is soluble in strong electrolytes. In seeking uses for surplus fats sodium allyl-a-sulfopalmitate and sulfostearate have been found to resemble sodium lauryl sulfate in surface-active and detergent properties.
A thumbnail history of the lightduty liquid syndets is (1) 90-odd % nonionic, (2) 5 0 % fatty alcohol sulfate or taurine sulfate solubilized by a small amount of organic solvent, or by nonionic, and (3) replacement of part of the active agent by variable amounts of alkylaryl sulfonate. T h e latest chapter in this story is development of heavy-duty liquid syndets. These differ from the heavy-duty solid syndets mainly in use of tetrapotassium pyrophosphate as the builder and in more restrained sudsing power. One died on the vine but another has gone national. T h e major packager in bottles now offers cans as well. A result of all of this is that liquid syndets are approaching 1 0 % of the total market and have nearly 10 times the sales of liquid soaps. T h e leading low-sudsing syndet showed the effect of competition by the big soapcrs in coming out with a product of greatly improved detergency. A new low-sudsing base is being offered for compounding. O p tical bleach content tends to be high in the low sudsers. This classification can be expected to find an expanded market as automatic clothes washers and dishwashing machines increase. VOL. 49, NO. 1 • JANUARY 1957
51 A
Syndets Millions of Pounds
Soaps Millions ol Pounds
Value Millions of Dollars
sulfonic acid as catalyst. Production other than from the peroxide plant is not expected in the near future. Probably completion will await an increase in uses for glycerol, a slow process, development of production costs which will price glycerol so low as to discourage imports of crude, or the production of syndets abroad on a scale which will make glycerol scarce there and cut out imports of crude. Meanwhile ion exclusion has been combined with ion exchange to refine crude by-product glycerol to USP specifications. T h e Shell plant for synthetic glycerol in the Netherlands should go into operation in 1957.
Production of soap and syndets 1 9 5 4 - 5 6 Foreign Nonionics
While these have usually been considered as nonionizing, there has been a concept presented of an equilibrium in solution with some large cations counterbalanced by hydroxy Is. At any rate their synergistic effects with anionics appear to be related to formation of loose complexes much like their addition compounds with phenols. Nevertheless they arc much less reactive than either anionic or cationic types and are sorbed from solution to a lesser degree. O n e concept of their use is the addition of 0.5 to 5 % of an oily or waxy nonionic such as the substituted phenol-ethylcne oxide condensation products to reduce dusting of the granular products. Another is to alter the surface-active properties of drilling mud to permit drilling at bottom-hole temperatures over 400° F., in one well at a depth of over 4 ' / 4 miles. This product of the petroleum industry thus aids the petroleum industry. T h e combining of two surplus commodities, fats and sucrose, as a nonionic surfactant has progressed through the pilot plant stage. Manufacture in one European country is already under way and both Pfizer and Millmastcr Chemical will offer versions of the product early in 1957. Initial use is expected to be in the food and pharmaceutical industries, but potential costs dictate household uses. Pubished data show the detcrgency to approximate that of active agents currently used in syndets. A variation of the process produces a fatty acid diestcr of 52 A
sucrose for use in shortenings and a six-plus ester for use as a drying oil. Glycerol
Glycerol production has reached an equilibrium situation with synthetic operation at the normal 7 5 % of installed capacity. T h a t derived domestically from soap manufacture and fat splitting can be expected to decline but little from year to year. It is supplemented in this market by low-cost crude imports, which declined this year. T h e total from these natural sources is estimated at about 146 million pounds in 1956. Refining capacity is far in excess of that amount. Production of synthetic glycerol increased in 1956 almost to duplicate the 146 million pounds from natural sources. T h e adequacy of capacity is indicated by an announcement of the Office of Defense Mobilization in the late summer that no more fast tax write-offs would be granted for this purpose. Unlike the situation in the inedible fat market, where an inevitable surplus sets the price at which it will move, glycerol prices must necessarily be set by the synthetic manufacturers, who supplement the inadequate supply from natural sources. T h e latter will get the price set by the synthetic product. In August Shell Chemical Co., the largest domestic producer, reduced the previously stable 30-cent price to 28 cents. T h e multipurpose plant to be installed by Shell at Norco, La., for hydroxylating allyl alcohol with hydrogen peroxide will use alkylaryl
INDUSTRIAL AND ENGINEERING CHEMISTRY
In the " O n e World" in which we live, the example of the U. S. is being followed abroad. American companies, or companies with American affiliations, offer syndets in most of Europe and South America. Roughly half the detergent needs of Israel, nearly half of those of the Netherlands, and a third of those of the United Kingdom are met by syndets. From there volume shades down, but there are few civilized countries of any size not producing and consuming them. A plant has just gone on stream in Ceylon and there is even an inquiry out for a plant for Tahiti. Disposal
T h e problems of syndets in the sewage works continue to plague both the U. S. and England and can arise in other countries as their detergents change from soap to syndets. Resistance to degradativc action by bacteria is a function of branching of the side chain; straight-chain compounds are much more susceptible. Pursuing the problem a British patent offers the solution of adding a quaternary ammonium halide, an apparently very expensive treatment. But Monsanto Chemicals, Ltd., has spent over 2.5 million dollars on effluent problems and continues to spend at the rate of over $200,000 a year. Damages of $40,000 were recently assessed against them for pollution of the River Dee. Legal action to bar some types of surfactants from the syndets of the "tight little isle" has been in the discussion stage. It could happen here.
