Colloidal products, decolorization

Decolorizing removal of suspended, colloidal, and dissolved impurities from liquid petroleum products by filtering, adsorption, chemical treatment, distillation, bleaching, etc. 

Use Ceramic products, refractories, colloidal suspensions, oil-well drilling fluids, filler for rubber and plastic products, films, paper coating, decolorizing oils, temporary molds, filtration, carrier in insecticidal sprays, catalyst support. 

Even smaller, nanometer size particles, can be prepared Irom cyclodextrin. These particles are useful as a carrier for pharmaceuticals and cosmetics. First, a solution of cyclodextrin in an organic solvent mixture is prepared, followed by the preparation of a water dispersion of surfactant. When the two components are mixed together a colloidal dispersion of microspheres is produced. Particles sizes range Irom 90 to 900 nm. Typical solvents are methanol, ethanol, isopropanol, and acetone. Solvents are used in the purification of xanthan gum to lower ash and to obtain a product with no traces of solvents. Lower alcohol is used as the solvent. Solvents have also been used to decolor fatty acid esters. Crude oils extracted by pressing or with solvents cannot be used in cosmetic products. Re-... 

Materials. Dodecylpyridinium bromide was synthesized by treating fractionally distilled 1-dodecane bromide in dry pyridine for 12 hr. The crude surfactant was recrystallized twice from acetone followed by decolorization with active charcoal in methanol solution. The resulting white crystal is a monohydrate of DoPBr. The critical micelle concentration (CMC) in aqueous solution as determined by electric conductivity method is 17.4 mM at 30°C in agreement with literature. Calf thymus DNA (sodium salt, SIGMA) was used as received. Residual (nucleotide) concentration was determined by a colloid titration using poly(potassium vinyl sulfate) as a titrant and Toluidine Blue as an indicator. 4 Propionyl- a-cyclodextrin (prop- a-CD) used as a neutral carrier was prepared by esterification of a-cyclodextrin (Tokyo Kasei Co.) with propionic anhydride in dry pyridine at room temperature for 12 hr. The reaction mixture was poured onto ice to obtain a gummy product which was then dissolved in acetone and precipitated in cold water. The dissolution-precipitation was repeated three times. The hydrophobicized oc-CD is a white powder. 

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