Alkyldiphenyl oxide disulfonates

The Dow Chemical Co. has been producing the alkyldiphenyl oxide sulfonates since 1958 under the trade name of Dowfax Surfactants. These products have been distributed globally for over 35 years and have capitalized on the solubility, rinsibility, and stability of this family of surfactants. Alkyldiphenyl oxide disulfonates are also produced and sold by Kao, Pilot Chemical Co., Rhodia, and Sanyo. In addition, a number of smaller suppliers are located in China, India, and France. 

Traditional uses of the alkyldiphenyl oxide disulfonates include (1) emulsion polymerization to yield faster run times with less reactor waste and smaller particle size (2) acid dyeing of nylon carpet fiber as leveling agents to promote an even distribution of dye, (3) crystal habit modification to alter crystal shape and size and (4) cleaning formnlations to provide solubilization in strongly acidic, caustic, and bleach environments. 

Alkyldiphenyl oxide disulfonate surfactants are a Friedel-Crafts reaction product of an olefin and diphenyl oxide using AlClj as a catalyst, as indicated in Figure 1. Diphenyl oxide is present in excess and is recycled. The reaction yields a mixture of monoalkyl and dialkyldiphenyl oxide. The ratio of mono- to dialkylation can be optimized depending on the end use of the products. 

FIG. 2 Process flow sheet for the manufacture of alkyldiphenyl oxide disulfonates. 

FIG. 3 Comparison of the detergency performance of linear alkylbenzenesulfonate and Cj alkyldiphenyl oxide disulfonate. The detergency comparison was conducted at 25°C using a Tergotometer and dust/sebum-soiled swatches of cotton, cotton/polyester, and polyester. Clean swatches of each fabric type were also included to measure redeposition. The detergency score is a summation of reflectance deltas of the clean and soiled swatches before and after washing. 

FIG. 7 Mols of surfactants rinsed from cotton skeins as a function of time. Disulfonate = Cjg alkyldiphenyl oxide disulfonate monosulfonate = Cj Unear alkylbenzenesulfonate nonionic = nonyl phenol ethoxylate (EO = 9). All rinsability studies were conducted at ambient temperature. 

FIG. 8 Modified Ross-Miles foam heights for C,2 linear alkylbenzenesulfonate and alkyldiphenyl oxide disulfonate at varying levels of Ca. Mono = linear alkylbenzenesulfonate Di = Cjg alkyldiphenyl oxide disulfonate. T = 0 represents the initial foam height. T = 5 represents the foam height after 5 min. 

TABLE 1 Ross Miles Foam Height Measurements for 1% Active 0, Alkyldiphenyl Oxide Disulfonate in Various Solutions at 25°C... 

As seen in Table 2, sodium hypochlorite bleach maintains excellent stability in the presence of the alkyldiphenyl oxide disulfonates, even after 319 days. Only 2-ethylhexylsulfate exhibited similar inertness to sodium hypochlorite. The bleach solution fared moderately weU with a number of surfactants to the 137-day point, but were not tested at 319 days due to the level of precipitate that developed. Two of the surfactants, phosphate esters and alkyl polysaccharide, exhibited very poor stabihty. 

The components (MAMS, MADS, DADS, DAMS Fig. 1) that make up the commercial blend of alkyldiphenyl oxide disulfonates were evaluated individually in both built and unbuilt formulations to determine the effect of equivalent weight on detergency performance (Fig. 10) Measuranents were obtained on dust/sebum and ground-in-clay soils on cotton, cotton/polyester, and polyester fabric. 

The C,g monoalkyldiphenyl oxide disulfonate component yielded the optimum detergency in the unbuilt formulation. In built formulations, the Cj di-alkyldiphenyl oxide disulfonate component showed optimum detergency. In... 

B. Degradation of Alkyldiphenyl Oxide Disulfonates in Activated Siudge... 

It can be concluded that the primary biodegradation of the Cjg alkyldiphenyl oxide disulfonate proceeds in a variety of aerobic environments (activated... 

In this volume of the Surfactant Series, originated by Martin Schick and published by Marcel Dekker, Inc., sugar-based surfactants snch as alkyl polygluco-sides are discussed in Chapter 1. Anionics such as alkyldiphenyl oxide disulfonates and a-sulfomethyl esters are presented in Chapters 3 and 4, and a... 

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