Accession Number : AD0815472

Title :   THERMODYNAMIC PROPERTIES OF ZIRCONIUM AND HAFNIUM HALIDES. PART II: HEAT OF FORMATION OF ZRCL3 QUANTITATIVE DIFFERENTIAL THERMAL ANALYSIS OF DECOMPOSITION REACTIONS.

Descriptive Note : Technical rept. 23 Jan 65-30 Sep 66,

Corporate Author : OKLAHOMA STATE UNIV STILLWATER RESEARCH FOUNDATION

Personal Author(s) : Freeman, Robert D.

Report Date : MAR 1967

Pagination or Media Count : 57

Abstract : Modifications to a solution calorimeter are described and results given for the performance of the calorimeter in determining the enthalpy of solution of THAM(Tris(Hydroxymethyl)amino- methane) in 0.2 N HCL. The enthalpy of solution of ZrCl4(s) in 0.2 N HCl and the enthalpy of reaction of ZrCl3(s) with 0.2 N HCl have been determined. From these and auxiliary data, the enthalpy of formation at 298.15 K of ZrCl3(s) is found to be -185.2 + or - 2.5 kcal/mole, and of ZrCl2(s), -130.2 + or - 5.0 kcal/mole. The approach to quantitative differential thermal analysis (QDTA) developed by Speros and Woodhouse has been tested for applicability to disproportionation reactions by studying the decomposition of lead and zinc carbonates; the results are in reasonable agreement with data obtained by other techniques. QDTA of the ZrCl3 disproportionation has been attempted under several conditions, but has so far been unsuccessful, primarily because of the increased reactivity of ZrCl3 with water vapor at elevated temperatures. (Author)

Descriptors :   (*ENTHALPY, ZIRCONIUM COMPOUNDS), (*ZIRCONIUM COMPOUNDS, CHLORIDES), (*CALORIMETRY), CARBONATES, DIFFERENTIAL THERMAL ANALYSIS, HIGH TEMPERATURE, PHASE STUDIES, EXPERIMENTAL DATA, HYDROCHLORIC ACID, LEAD(METAL), ZINC, DECOMPOSITION, CONTROLLED ATMOSPHERES, CARBON DIOXIDE, REACTION KINETICS, AMINO ACIDS, THERMAL DIFFUSION, MELTING POINT.

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE