Preparation of Standard Chromous Sulfate or Chromous Chloride Solutions of Determinate Concentration

Lingane, James J.; Pecsok, Robert L.

doi:10.1021/ac60017a006

Cited by 40 publications

(23 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 0.1 m EDTA solution was prepared from the disodium salt of EDTA, and the pH was adjusted to the desired value by the addition of 0.1 m NaOH prior to final dilution. The 0.1 m chromous titrant solution in 0.1 M HC1 was prepared by the method of Lingane and Pecsok (1948). Its concentration was checked by potentiometric titration of a standard CuS04 solution.…”

Section: Methodsmentioning

confidence: 99%

The Formation of Hydridocobalamin and Its Stability in Aqueous Solutions

Tackett¹,

Collat²,

Abbott³

1963

Biochemistry

View full text Add to dashboard Cite

Section: Methodsmentioning

confidence: 99%

The Formation of Hydridocobalamin and Its Stability in Aqueous Solutions

Tackett¹,

Collat²,

Abbott³

1963

Biochemistry

View full text Add to dashboard Cite

“…1.4091 (lit.20 n20n 1.4116); ir (CC14) 975 cm"1 (trans CH=CH); uv (95% EtOH) end absorption (e 18 at 210 µ); nmr (CC14) 0.96 [18 H s, (CH3)3C] and 5.26 (2 H s, vinyl CH); mass spectrum m/e (rel intensity) 140 (10, M + ), 125 (54), 84 (23), 83 (81), 70 (80), 69 (100), 57 (52), 55 (43), and 41 (46).…”

Section: Experimental Section18mentioning

confidence: 99%

“…Earlier stereochemical studies of alkyl-substituted vinyl radicals17 have indicated that these intermediates are nonlinear with a relatively low energy barrier to inversion.17® Studies of the reduction of stereoisomeric vinyl halides176•0 such as 40, 42, and 43 have suggested that the rates of radical inversion (e.g., 37 t=: 39) and the rates of electron transfer to such radicals (e.g., 37 -* 38 or 39 -* 41) are comparable in magnitude. Thus, when a solution of sodium naphthalenide in THE was added to a THE solution of the cis chloro olefin 40 at 0°, the olefinic product contained 31% of the cis olefin 25 and 69% of the trans olefin 24.176 A similar electrochemical reduction of the iodo olefin 42 produced a mixture containing 30% of the cis olefin 25 and 70% of the trans olefin 24.170 In each of these studies, equilibration of the vinyl radicals was incomplete because reduction of the corresponding trans halo olefin (e.g., 43) produced olefin mixtures containing 85-94% of the trans olefin 24.176•0 These results are in contrast to an earlier study in which the addition of a solution of the cis chloro olefin 40 in methylcyclohexane to a cold (-33°) solution of Na in liquid NHs was reported17"1 to yield only the cis olefin 25. We have examined the reduction of the cis chloro olefin 40 with cold (-33°) solutions of Na and f-BuOD in HMP-THF employing both normal and inverse addition procedures (see Table II). In all cases, the olefinic product contained 79-82% of the trans olefin 24 and this product 24 (81-85% di species and 15-19% do species) had been formed primarily by "protonation" of an organometallic (or anionic) intermediate.…”

mentioning

confidence: 99%

Reactions involving electron transfer. V. Reduction on nonconjugated acetylenes

House¹,

Kinloch²

1974

J. Org. Chem.

View full text Add to dashboard Cite

The reduction of 3-hexyne (9) and of 1-hexyne (7) with solutions of sodium in hexamethylphosphoramide (HMP)-tetrahydrofuran (THF) mixtures has been studied. In the absence of an added proton donor, the internal acetylene was reduced to mixtures of the 2-hexenes 28 and 29 and the 3-hexenes 24 and 25. However, in the presence of a proton donor, f-BuOH, only the 3-hexenes were produced. At low temperature (-33°) in the presence of excess Na and i-BuOH, >95% of the olefin product was the trans isomer 24. At higher temperatures (0 or 25°) or employing an inverse addition procedure to limit the Na concentration, mixtures containing 80-90% trans olefin 24 and 10-20% cis olefin 25 were obtained. Comparable mixtures (77-82% 24 and 18-23% 25) were formed when 3-chloro-cis-3-hexene was reduced under various conditions with solutions of Na and -BuOH in HMP-THF. These results are compared with reductions effected by solutions of Na in liquid NH3 and the reaction pathways operative in these reductions are discussed.

show abstract

“…Because the half-wave potential for copper (11) in an acid tartrate medium is less negative than that of titanium, there is a limit to the concentration of copper that can be present without the occurrence of interference in the polarographic determination of titanium. Iron (111) also constitutes an interference (23).…”

Section: Removal O F I N T E R F E R E N C E Smentioning

confidence: 99%

The Polarographic Determination of Titanium in Steels and Nickel-Base Alloys

Graham¹,

Hitchen²,

Maxwell³

1952

Can. J. Chem.

View full text Add to dashboard Cite

Titanium in steels and nickel-base alloys can conveniently be determined polarographically after electrolysis of a solution of the alloy in a n~ercur)l-cathode cell. A well-formed wave, the height of which is directly proportional to the concentration of titanium in the solution, is recorded using a supporting electrolyte that is 1.0 111 in tartaric acid, 0.5 AT in sulphuric acid, and 1.2 n/f in ammonium sulphate.The method is one of good precision arid yields values in excellent agreement with those given by umpire methods for samples of basic ope~l-hearth steel, 18-11 chromium-nickel steel, Monel, Inconel "W", and Nimonic 75 and 80. INTRODUCTIONThe only earlier work on the polarographic determination of titanium in metallurgical products appears to be that of Zan'ko, Geller, and Nilcitin (25) who proposed a method for the determination of this element in cast irons and steels. They report the determination of titanium in an acid tartrate medium after treating a solution of the alloy with aluminum dust. We have not been able to remove the interference of iron (111) by the use of this reducing agent; furthermore, the introduction of an appreciable concentration of aluminum ion is undesirable (3).Recent work in this laboratory on the polarographic deternliilation of titanium in rocks and minerals (4) has shown that very good polarographic waves for titanium are obtained in a medium containing tartaric acid, sulphuric acid, and ammonium sulphate. Interfering ions are removed by prior electrolysis of the solution in a mercury-cathode cell. The application of such a method t o the determination of titanium in steels and nickel-base alloys is discussed in the present paper. REMOVAL O F I N T E R F E R E N C E SBecause the half-wave potential for copper (11) in an acid tartrate medium is less negative than that of titanium, there is a limit to the concentration of copper that can be present without the occurrence of interference in the polarographic determination of titanium. Iron (111) also constitutes an interference (23). Electrolysis in a mercury-cathode cell is a very convenient and efficient way of removing from solution iron, copper, and nickel-and a score of other elements (12)-all without the introduction of foreign salts, and often in less time than that required by other procedures. In such an electrolysis chromium is not easily removed quantitatively but the chromium remaining in solution causes no interference in the determination of titanium, even in alloys high (20%) in chromium. The chromium content of the solution being polarographed should be Manuscript received Febrzrary 25, 1952.

show abstract

Preparation of Standard Chromous Sulfate or Chromous Chloride Solutions of Determinate Concentration

Cited by 40 publications

References 15 publications

The Formation of Hydridocobalamin and Its Stability in Aqueous Solutions

The Formation of Hydridocobalamin and Its Stability in Aqueous Solutions

Reactions involving electron transfer. V. Reduction on nonconjugated acetylenes

The Polarographic Determination of Titanium in Steels and Nickel-Base Alloys

Contact Info

Product

Resources

About