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Surfactants with branched hydrophobes have gained considerable interest, since these can be used in formulations for laundry cleaning at a wide range of conditions. The claims range from improved dissolution rate to hardness tolerance and stain removing efficacy. In contrast to the historically known heavily branched surfactants, novel branched surfactants are less compromised by increased biodegradability. These properties find their basis in the structural characteristics of the hydrophobe, such as number, position, and type of alkyl chain branches. Our current understanding of structure-property relations, however, is hampered by the lack of generic methodology needed to obtain structural data on hydrophobe branching. A nuclear magnetic resonance (NMR) approach was developed by which we could obtain a comprehensive set of quantitative hydrophobe branching parameters in alcoholbased surfactants. The 13 C and 1 H NMR spin systems of hydrophobe branched species were assigned by means of twodimensional NMR techniques. These assignments allowed the quantitative assessment of these branched species by straightforward signal integration in the 1 H and 13 C NMR spectra. The quantified NMR data can be used to understand product performance and the biodegradation of surfactants with branched hydrophobes.Paper no. S1451 in JSD 8, 73-82 (January 2005). KEY WORDS:Alcohol, alkyl chain, branching, feedstocks, hydrophobe branching, mid-chain branching, NMR, nuclear magnetic resonance spectroscopy.Since the switch by the industry from the poorly biodegradable, tetrapropylene-derived, and heavily-branched alkylbenzene sulfonates to the more quickly biodegradable linear alkylbenzene sulfonates (LAS) in the early 1960s, the surfactants used for laundry applications have differed mainly only in the type of hydrophilic group. Thus, the range of surfactant families available to the product developer has traditionally been limited to those based on sulfonates (LAS), carboxylates (soaps), sulfates, ethoxylates, or ethoxysulfates (1). In the last 10 yr, the range of hydrophiles has been extended even further, and new surfactants have come onto the market (2,3). With the exception of alkylbenzene-based materials, most surfactants are derived from olefins and alcoholbased materials that originate from petrochemical or oleochemical feedstocks. Until recently, there was limited room to maneuver with the hydrophobe structure. Alcohol feedstocks with branching at the β-position of the alkyl chain could be produced efficiently by the Oxo process, and they provided a good compromise between cleaning performance and biodegradability (5). In the conventional and modified Oxo processes (C-Oxo and M-Oxo, respectively), the degree of β-branching typically varies between 55 and 20%, respectively. Also, materials were available with high branching (HB) or random moderate branching (RMB) at the midchain positions of the alkyl chains, but owing to their unfavorable biodegradability, they were applicable only in niche applications. A rough overview of t...

In a previous paper we reported that photoexcited SO2 reacts with alcohols, ethers, sulfides and chlorides to form a-substituted alkanesulfinic acids'. Here we report the formation of carbenium ions by reaction of photoexcited SOz with trialkyl orthoformates or benzaldehyde dimethyl acetal :When a 2.0 molar solution of e.g. trimethyl orthoformate in liquid SO, had been irradiated with UV-light' at -75°C for 18 h, ca. 40% of the orthoformate had reacted of which 65% was found back as the trimethoxymethyl cation** as appears from the following evidence.

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