A number of new diesterquats and amidoester quats were synthesized and tested for biodegradation and softening. Methyldiethanolamine, 3-methoxylpropylamine, diethanolaminopropylamine, aminoethylethanolamine, dimethylethanolamine, and diethanolamine were reacted, either "as is" or after alkoxylation, with tallow fatty acid and further converted into dialkyl quats. The diesterquat from diethanolisopropanolamine was by far the best of the ester quats synthesized in overall biodegradation, softening, and cost/ease of manufacture. It appears that two ester groups are needed for ready biodegradation as opposed to an amide-ester combination. Increasing unsaturation of the alkyl chains within a molecule increases its rate of biodegradation slightly.Dihydrogenatedtallow dimethyl ammonium chloride (DHTD-MAC), ditallowamidoamine quat, and ditallow imidazoline quat (Scheme 1, Structures 1, 2, and 3, respectively) are traditionally used to prepare fabric softeners. For environmental reasons, esterquats (Structure 4, Scheme 1) based upon triethanolamine (TEA) have been the main ingredient in European fabric softeners for about 9 yr. A methyldiethanolamine (MDEA) esterquat and an epichlorohydrin esterquat are also used in large volume (1). Esterquats biodegrade rapidly and thus are environmentally sound (2,3). Both chemical and biochemical hydrolysis of the two ester bonds can occur, which greatly speeds biodegradation.While having an excellent environmental profile, the TEA esterquats have been plagued by mediocre performance compared to traditional molecules. The objective of this research was to develop a novel, biodegradable, highperformance esterquat with potential uses as a fabric softener, paper debonder, and hair/skin conditioner.Fabric softeners are quaternary ammonium salts, or quats for short. The cationic (positive) charge allows them to neutralize static negative charges that typically are present on surfaces. To be really effective, a fabric softener molecule needs two alkyl chains, which result in very low water solubility. However, the molecule must be water-dispersible so it can be diluted and produced as a saleable product.Over the last few years a number of new softener/conditioner molecular structures have been synthesized (4-8). Slight changes in the structure of TEA esterquats have im-SCHEME 1. Commercial quaternaries. Structure 4. Ester quat technology Structure 3. Imidazoline quat Structure 2. Amidoamine quat Structure 1. Dihydrogenatedtallowdimethylammonium (DHTDMAC)

Triethanolamine (TEA)-based esterquat has been the primary ingredient in European fabric softeners for several years and is becoming the global molecule of choice. Although it has an excellent environmental profile, TEA esterquat has been plagued by mediocre performance compared to historical molecules such as dihydrogenated tallow dimethyl ammonium chloride and ditallow imidazoline quat. In this study, the chain lengths, the level of unsaturation, and the source of the raw material (tallow or palm stearine) were varied to better understand their effect on softening and dispersion viscosity. Palm stearine derivatives generally soften as well as tallow derivatives despite the lower C18 content of palm. Various additives were examined to improve dispersibility and other properties such as dye transfer inhibition (DTI) and ease of ironing. DTI is normally accomplished in the wash cycle by additives to the laundry detergent such as polyvinylpyrrolidone. In this study, we found that fabric softener molecules themselves provide some color care, or DTI. Certain additives to fabric softeners, such as monoalkylquats, greatly enhance the color care of the fabric. DTI treatment in the rinse cycle of the washing sequence makes more sense scientifically and to the consumers, since fabric softeners are designed to coat the textile. Because no competing detergency operations are occurring during the rinse cycle, color care works well in the fabric softener cycle. Addition of organosilicones to fabric softeners reduces wrinkling of fabrics and makes them easier to iron. Softening increases slightly.For the past several years, triethanolamine-based esterquat (TEA EQ) has been the primary ingredient in European fabric softeners, thus slowly becoming the global molecule of choice. It has an excellent environmental profile, being readily biodegradable and having reasonably low aquatic toxicity (1-3). However, the typical molecule supplied commercially has been plagued by mediocre softening performance compared to historical molecules such as dihydrogenated tallow dimethyl ammonium chloride (DHTDMAC) and ditallow imidazoline quat (4-6). The goal of this project was to improve the softening of TEA EQ and possibly enhance other properties of TEA EQ fabric softener formulations. The topics for study in this project (7) were: (i) structure vs. softening (The effects of chain length were explored using tallow and palm stearine. Also, the effect of unsaturation on softening was examined.); (ii) dye transfer inhibition; and (iii) easy ironing. EXPERIMENTAL PROCEDURESMaterials. Dimethyl sulfate and TEA were obtained from Aldrich (Milwaukee, WI). Palm stearine fatty acids, tallow fatty acids, DHTDMAC, and the organosilicone were obtained from Goldschmidt Chemical Corporation. The commercial fabric softeners were obtained in consumer stores in Germany.Preparation of quats. Hydrogenated and partially hydrogenated tallow and palm stearine fatty acids were prepared using standard hydrogenation methods with nickel catalysts (8). The various types ...