Reference

Aqueous polymerization of methyl methacrylate initiated by N-bromosuccinimide-reducing metal salt redox couple

Aqueous polymerization of methyl methacrylate initiated by N-bromosuccinimide-reducing metal salt redox couple. Banthia, Ajit K.; Palit, Santi R. (Dep. Phys. Chem., Indian Assoc. Cultiv. Sci., Calcutta, India). J. Indian Chem. Soc., 54(5), 513-18 (English) 1977. CODEN: JICSAH. DOCUMENT TYPE: Journal CA Section: 35 (Synthetic High Polymers) NBS [128-08-5] can not initiate the polymn. of Me methacrylate [80-62-6] by itself in the dark, but is a good initiator in the presence of UV light or a reducing metal salt activator. The rate of polymn. under N is proportional to the square root of NBS concn. and to the 1st power of monomer concn. with an overall activation energy of ~5.25 kcal/mol. For vanadyl sulfate [27774-13-6] as the activator, the polymn. rate shows the usual square root dependence on activator concn. in the range 1.0 ′ 10-4-5.0 ′ 10-4 mol/L, but as the activator concn. increases beyond 5 ′ 10-4 mol/L, the polymn. rate becomes almost independent of the activator concn.

Studies of factors affecting uranium determinations by automated coulometric titration (New Brunswick Laboratory/Davies-Gray Method)

Studies of factors affecting uranium determinations by automated coulometric titration (New Brunswick Laboratory/Davies-Gray Method). Harrar, J. E.; Boyle, W. G. (Lawrence Livermore Lab., Univ. California, Livermore, Calif., USA). Report, UCRL-52060, 27 pp. Avail. INIS; NTIS From: INIS Atomindex 1976, 7(12), Abstr. No. 272307 (English) 1976. DOCUMENT TYPE: Report CA Section: 71 (Nuclear Technology) Section cross-reference(s): 79 The method's errors are defined to ascertain its abs. accuracy. An anal. technique was developed to examine vanadyl sulfate [27774-13-6] diluent for V(V). None could be found in any of the lots tested. Certain lots of reagent-grade H3PO4 contained an unidentified impurity that caused high generator-electrode potentials and a pos. error. The current-potential characteristics of the generator electrode were measured. 27774-13-6 and 7440-61-1 are cas registry numbers of chemicals which are used as reagents here. The data indicated that a significant fraction of U(IV) was oxidized directly during the early stages of titrn. By using equations theor. applicable to such a titrn., a negligible difference was found between the inflection point of the titrn. curve and the equivalence point in the titrn. However, the actual exptl. curves did not agree with the theor. curves early in the titrn. Measurements of the background current indicated a level equiv. to .apprx.0.2 mg U. The evaluation of the reagent delivery system used in the automated analyzer revealed adequate reproducibility. .