J. Fred Hazel

Studies on the extraction of chromium(VI) by ketones

Abstract A study of the extraction of chromium(VI) from aqueous media by ketones was made. Extraction of chromium was found to be most efficient from aqueous hydrochloric acid solutions. A mechanism for the extraction of chromium(VI) from aqueous hydrochloric acid solutions by methyl isobutyl ketone is proposed involving the formation of a receptor in the organic phase, the exchange of the chloride ion of the receptor for the anionic chromium(VI) species of the aqueous phase, and the solvation of the extracted chromium species. The differences in the abilities of various ketones to extract chromium(VI) from aqueous hydrochloric acid solutions, and the differences in the extraction of chromium (VI) from various aqueous acids by methyl isobutyl ketone are attributed to the differences in the formation of receptors.

Interaction of inorganic macromolecular systems with surface-active agents

Abstract Several inorganic macromolecular systems and ionic surface-active agents have been studied in relation to the effect of the surface-active agents on the stability of colloidal suspensions of the inorganic substances, as well as the effect of the inorganic macromolecules on the critical concentration (CMC) of the surface-active agents. Iron (III) oxide, aluminum oxide, manganese (IV) oxide, and arsenic (III) sulfide comprised the inorganic systems. Potassium salts of a series of fatty acids, alkyl sodium sulfates, alkyl amine hydrochlorides, and alkyl pyridinium chlorides were used as the colloidal electrolytes. The stability of the colloidal suspensions in the presence of the surface-active agents varied inversely with the chain length of the surfactant, in the cases where the surface-active ion possessed a charge opposite in sign to that of the colloidal particle. In such systems the minimum concentration required to cause complete flocculation decreased sharply with increase in chain length of the surfactant. At higher concentrations of the surfactants a restabilization of the inorganic systems was observed owing to recharging of the colloidal particles. Logarithmic plots of chain length versus flocculation values approached straight lines as the concentration of the sols decreased. When the surface-active ion had the same sign of charge as the colloid, flocculation occurred only at high concentrations and was independent of chain length. The flocculation value was the same for all members of a homologous series in the latter case. The critical concentration of the anionic surfactants were found to be higher in iron (III) oxide sols than in water, the difference in CMC values being attributed to adsorption of the surfactant by the iron (III) oxide. In a similar manner, manganese (IV) oxide increased the critical concentration of dodecylamine hydrochloride. The critical concentrations of the surface-active ions were unaltered in the presence of colloid particles of the same sign.

The separation and photometric determination of chromium and vanadium

A study was made on the extraction of hexavalent chromium from hydrochloric acid solutions with methyl isobutyl ketone. Quantitative extraction was accomplished from 3 N hydrochloric acid with 25 ml of solvent. Under these conditions, it was found that chromium could be extracted from vanadium. A procedure was developed for the colorimetric determination of chromium in the ketone phase and of vanadium in the aqueous phase. The analytical procedure was used to analyze standard steel samples for chromium and vanadium, and the results obtained by this method were found to agree with the accepted values.

A spectrophotometric method for the determination of nickel

Abstract A photometric method for the determination of nickel using versene is described. Up to 20 mg of nickel can be determined with a maximum deviation of ± 0.10 mg. The effect of interfering elements, concentrations, accuracy and limitations of the method are discussed.

Electron microscopy of labile alkali silicate solutions

Abstract Aqueous solutions of potassium silicate have been examined by electron microscopic methods. Particle size and distribution has been shown to be dependent on the history of the silicate solutions. Particle studies of the alkali silicate in the presence of pinacyanol chloride have been correlated with the spectral behavior and stability of the dye.

Lability of aqueous solutions of potassium silicate

Abstract The lability of potassium (1:3.45) silicate solutions has been observed by studying their effect on the spectra of pinacyanol chloride and by noting the behavior of mixtures of silicate and dye with a cation exchange resin. The present studies employing this cationic dye indicated complex formation between silicate and dye and showed that the solutions of silicate are extremely labile at concentrations below about 0.75% K 2 0·3.45SiO 2 . Temperature and concentrations were found to have a marked effect on the lability.

Thermal gravimetric studies of orthophosphates

Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania ( R ~ v ~ 26 Ap~l 19~) Disodiumorthophosphate produces tetrasodltun pyrophosphate when calcined at elevated temperatures (I). Monosodlum orthophosphate, NaH2P04, when heated to a temperature of about 250°C yields Na2H2P207, and this in turn produces insoluble metaphosphates after heating to higher temperatures (2). These reactions were investigated by means of water vapor pressure measurements over various phosphate systems (3). No thermal analysis studies of sodium orthophosphate mixtures have appeared in the literature. The present paper deals with a thermogravimetric analysis of trisodium orthophosphate~ dlsodlum orthophosphate~ monosodium orthophosphate~ phosphorus pentoxide, orthophosphoric acid, and mixtures of the latter with trisodium p h o s p h a t e . Experimental Apparatus. The thermobalance has been described elsewhere (4~ 5). Procedure. The TGA was carried out in a static air atmosphere at a heating rate of 8°/minute to a temperature of 9OO°C with 100 m E samples. Reagents. The chemicals were BakerWs analytical grade Na3PO4*I2H20 ~ Na2HP04*~O ~ NaH2P04, 85~ phosphoric acid and anhydrous phosphorus pentoxide. R e s u l t s T r i s o d i u m o r t h o p h o s p h a t e d o d e c a h y d r a t e b e g a n t o l o s e i t s h y d r a t i o n w a t e r a t 60°p b u t t h e l o s s was n o t c o m p l e t e u n t i l a t e m p e r a t u r e o f 200 ° was r e a c h e d . T h e r e was no w e i g h t l o s s a b o v e 200 ° . D u r a l ( 6 , 7) o b s e r v e d a w e i g h t l o s s up t o 230 ° w i t h a s a m p l e o f t h i s compound.

Application of absorption spectrum of sodium vanadate to determination of vanadium

Abstract A method is proposed for the determination of small amounts of vanadium as found in certain ores, rocks and minerals. After fusion of the sample, the 8-hydroxy-quinoline complex is extracted with chloroform and converted to sodium ortho-vanadate. The absorbancy of this compound is measured at a wavelength of 270 mμ. The present method does not depend on the formation of a colored complex and, hence, is independent of such conditions as time and temperature.

Flocculation of pinacyanol chloride in alkali silicate solutions

Abstract Aqueous solutions of sodium and potassium silicates have been used as coagulating agents for the cationic dye pinacyanol chloride. The stability of the dye has been shown to be dependent on the concentration and the history of the silicate as well as on the concentration of the dye. Spectral changes of the dye accompanying flocculation were observed.

Low temperature studies with colloidal silicic acid

Abstract 1. 1. Silica sols prepared with mineral acids and with ion-exchange resins have been frozen at −15°, −25°, −35°, −45°, −55°, −65°, and −190°C. 2. 2. The effects of hydrogen-ion concentration, rate of thawing, temperature of aging the frozen systems, and presence of electrolytes were investigated. 3. 3. The following factors were found to increase the stability of the systems: (a) low temperature of freezing, (b) low temperature of aging, (c) rapid rate of thawing, and (d) presence of lithium chloride and calcium chloride.