Hydrotropic polymer hydrotropes

Further development in the area of alternate value-added products for improving economics included other oxygenated sulfur compounds [246,247], This invention included alkylated 2-(2-hydroxyphenyl) benzenesulfinic acid and 2-(2-hydroxyphenyl)-benzenesulfonic acid compounds and compositions which consist essentially of 2-(2-hydroxyphenyl) benzenesulfinic acid, 2-(2-hydroxyphenyl)-benzenesulfonic acid and/or substituted derivatives. The compositions are useful as hydrotropes and are also of use as, or as starting materials for, surfactants, and as starting materials for the synthesis of other useful chemicals such as, polymers and resins, solvents, adhesives, and biocides. 

Liquid products are approximately 50 to 60 percent water, with the remainder being a combination of surfactants, builders, foam regulators, enzymes and enzyme stabilizers, hydrotropes, antiredeposition polymers, optical brighteners, corrosion inhibitors, dye, and perfume. Two-in-one formulations also contain antistatic and fabric softening ingredients. Liquid systems require careful selection and blending of raw materials to achieve a stable product. Special attention is necessary for the following items. 

It is important to ensure that the modified forms, both monomers and polymers, of hydrotropic agents maintain their hydrotropic properties. Fig. 5A shows the enhancement of aqueous solubility of paclitaxel as a function of the concentration of 2-VBOPNA, 6-VBOPNA, and PNA. Two monomers, 2-VBOPNA... 

While the structure of the hydrotropic moiety of the polymer is the most important factor in hydrotropy, other factors can also contribute to the overall hydrotropic property of the polymers. The spacer between the polymer backbone and the hydrotropic moiety is one key factor affecting the overall hydrotropy. Two different hydrotropic polymers based on V-PNA have different hydrotropic properties depending on the nature of the spacer. The paclitaxel solubility in P(6-VBOPNA) increased to a larger extent than in poly(6-allyloxy-V-PNA) (P(6-APNA)), where the aromatic spacer was replaced with a linear chain. 

Fig. 4 Various hydrotropic monomers (A), and an exemplary synthetic scheme of a hydrotropic polymer, poly(2-(4-vinylbenzyloxy)-V-picolylnicotinamide) P(2-VBOPNA)] (B).

Because hydrotropic polymers can be diluted when introduced into aqueous solution, cross-linked hydrotropic polymers, i.e., hydrotropic hydrogels, were prepared. Hydrotropic hydrogels are prepared by polymerization of hydrotropic monomers in the presence of cross-linking agents. Despite the cross-linking of linear hydrotropic polymer chains, the hydrogels maintained the hydrotropic property. The hydrotropic hydrogel... 

Poor water solubility of drugs and new chemical entities presents major challenges in the development of clinically useful formulations. Of the various approaches used for enhancing the solubility of poorly soluble drugs, polymeric delivery systems have been used effectively. Paclitaxel has been used as a model hydrophobic drug to show the effectiveness of solubility-enhancing properties of various polymeric delivery systems. Recently, hydrotropic polymers were developed based... 

Lee, S.C. Acharya, G. Lee, J. Park, K. Hydrotropic polymers Synthesis and characterization of polymers containing picolylnicotinamide moieties. Macromolecules 2003, 36, 2248-2255. 

Many studies of these applications have been reported reflecting the importance of these compounds in the commercial realm. Among the recent examples of new molecules with hydrotropic action may be mentioned vitamin C [12], useful for sunscreen formulations [13,14], Other hydrotropes reported as new are diisopropylnaphthalene sulfonates [15], while the application of hydrotropes to solubilize pharmaceuticals continues to be extensive [16-24], Long-chain amphi-hiles [25] and polymers [26] have been shown to exert hydrotropic action under certain conditions. Among the most recent developments should be mentioned the alkyl polyglucosides as hydrotropes [27], They have been shown to be useful in strongly alkaline systems [28],... 

Viscosity modifiers are used to achieve the desired product viscosity. These include alcohols, salts, polymers, and hydrotropes. Viscosity adjustment with polymers, particularly in the high surfactant concentrations of ultra LDLD formulations, can be challenging. Acids, such as citric or sulfuric acids, or bases, such as hydroxide, are also added to bring the product pH to the desired level. 

Fatty alkanolamides are mainly used as foam stabilizers, but they can also have a large effect on the viscosity of an LDLD formulation, usually increasing it. Other viscosity modifiers include hydrotropes such as alcohol, SXS, SCS, urea, and water-soluble polymers. However, not all of these have the same magnitude of effect, which depends on the surfactant system in the product. 

Naxonate . [Ruetgers-Nease] Sulfonates hydrotrope, stabilizer, sdubi-liser for detogents, inks, elecooidating baths, dyestu, polymers. 

Ammonium xylenesulfonate Ammonium xylene-sulphonate Benzenesulfonic acid, dimethyl-, ammonium salt EINECS 247-710-9 Eltesol AX 40 Hartotrope AXS Naxonale 4AX Stepanate AXS Xylenesulfonic acid, ammonium salt Hydrotrope, cloud point depressant, stabilizer, solubilizer used in formulating detergents, inks, electroplating baths, dyestuffs, polymers. Albright Wilson UK Ltd. Hart Prod. Ruetgers-Nease Stepan Canada Stepan. 

Lee SC, Acharya G, Lee J, Park K. Hydrotropic polymers synthesis and characterization of polymers containing picolyl-nicotinamide moieties. Macromolecules 2003 36 2248-2255. 

Hydrotropes are small, highly water soluble additives that increase markedly the solubility of other components, including surfactants, in water. They are employed very widely in industry. In fact, they only work when the insoluble phase is a mesophase with high molecular mobility (e.g. polymer coacervate or surfactant mesophase). They include weakly self-associating elec-... 

A particularly attractive application of hydrotropy in organic synthesis arises when the product is bulkier than the reactant, with the result that it has lower solubility than the reactant in the hydrotrope solution. Consequently, it selectively precipitates out of the reaction mixture and can be easily filtered out. Then the hydrotropic solution can be recycled, thus minimizing the environmental hazards associated with waste disposal. An important example is the synthesis of Diels-Alder adducts that act as flame retardants for polymer blends and formulations. One of these is also used in the manufacture of the pesticide Endosulfan. The reaction involves a diene such as hexachloro-pentadiene or anthracene and a dienophile such as p-benzoquinone or maleic anhydride. The following typical reaction carried out by Sadvilkar (1995) gave excellent results ... 

---