Catalytic Effect of 1,10-phenanthroline on the Kinetic Studies of D-galactose by Cr(VI) in CPC Micellar Media

Introduction

Diverse valency of metal ions, like chromic acid, have been used to oxidatively reduce various reducing sugars ^1–12. Such studies provide insight into the chromium chemistry in the environment where the hexavalent-charged metal ion appears as a chemical hazard due to its carcinogenic and mutagenic activity.^13–15 Biomolecules interact with intermittent chromium states to induce toxicity.¹⁵ In vivo, reduction may occur due to the presence of reduced sugars. Hence, their survey appears to be pertinent in this context. Reports have arrived^1,16 of various ketohexoses undergoing oxidation in aqueous acid ambiance with various transition metal ions. Among diverse chelating agents^{8, 17–37}, phen, bipy chelating agents appear to be the most elegant^38–42 chelating agents used to promote chromic acid oxidation of several organic substrates These never undergo co-oxidation along with the substrate. 1,10-phenanthroline acts as a chelating agent in micro-heterogenous reveals, similar to biological simulations, to uphold the suggested reaction path initially in vivo chromium reduction (VI).

Experimental

Reagents and Materials

D-galactose (E-Merck), 1,10-phenanthroline (E-Merck), K₂Cr₂O₇ (AR, BDH), N-cetylpyridinium chloride (CPC) (E-Merck), and commercially available highest grade other chemicals were used. All solutions are set up by applying conductivity H₂O.

Method and Kinetic Dimensions

Necessary chemicals, acids, catalyst (phen),(i) [substrate ]_T>>[hexavalent chromium)]_T and  (ii) [phen]_T >> [hexavalent chromium]_T),  D-galactose, i.e., familiar amounts of the substrate and oxidant solution were separately thermostated  (± 0.1⁰C) under experimental conditions. A specific quantity of chromic acid was mingled with the reaction mixture to trigger the reaction. The titrimetric quenching technique^[19] monitored hexavalent chromic acid’s disappearance rate and tracked the reaction progress. The usual mathematics was used to calculate pseudo 1^st order rate constants (k_obs). Investigation into the probable decomposition of surfactant by chromic acid revealed that the decomposition rate was insignificant. Usual estimation procedures were executed to detect errors in various rate constants and activation parameters.⁴³

Product Analysis and Stoichiometry

Paper chromatography^{3, 6, 7} was used to identify the reaction product under the reaction condition such that [hexavalent chromic acid] <<[ D-galactose]_T. Here, aldonic acid was detected as the major product. Eluant water– acetic acid – butan-1-ol (volume as in ratio 5:1:4 ) was used in paper chromatographic detection. A specific reagent.⁴⁴, beta-anisidine, was employed specifically for D-galactose identification, along with a tri-stage dip of AgNO₃, NaOH, and Na₂S₂O₃^[45]. These two developing reagents were used to visualize paper chromatography.

Thus, the stoichiometry of the reaction is

Results with discussion section

Dependability on [Hexavalent chromic acid]_T

When [D-galactose] _T>> [1,10- phen] _T>> [chromic acid] _T was maintained, both in occupancy  and absenteeism of phen, it was noticed that the disappearing rate of hexavalent chromic acid demonstrated a 1^st order dependency on chromic acid. This 1^st order dependency on hexavalent chromic acid was also depicted with surfactant CPC presence. Pseudo-1^st order rate constants (k_obs) were assessed by graph of log [Cr (VI)]_t  vs. time (t),

Figure 1: [Cr(VI)] = 60*10-5 (M), [D-galactose] = 1*10-2 (M), [H2S04] = 5*10-1(M), [1,10-phen]T  = (0-14)*10-3 (M), T  = 22 °C(a),  32°C(b),  40°C(c). Click here to View Figure

Dependability on [phen]_T

The positive intercept was obtained from the liner plot (r> 0.99) of k_obs vs. [phen]_T, which measures the existance of the comparatively sluggish with uncatalysed route. There is a good agreement with the pseudo-1^st  order  rate constants (k_obs(u)) estimated, in absenteeism of phen,  it has been acquired from the intercepts of graph of k_obs(T)  vs.  [phen]_T. These surveillances may be equated as:

The above equation holds good both in occupancy and absenteeism  of CPC surfactant. Table 1 provides some k_cat values  along with the activation parameters. In course of reaction, loss of phen occours because of generation of Cr(III)-phen inert complex compound.

Figure 2: [Cr(VI)] = 6*10-4  (M), [D-galactose]  = (10-30)*10-3  (M), [phen]  = 90*10-4 (M),  [H2SO4]  = 0.5 (M), T = 22°C, [surfactant] = 0 (M)  (in absence of CPC), [surfactant] = 6*10-3 (M)   (with CPC). Click here to View Figure

Dependability on [Substrate]_T

Graph of k_obsvs. [D-Galactose]_T establishes that catalyzed path leads to 1^st order dependency on  [substrate]_T, so,

In occupancy of  CPC surfactant, is obligatory for maintaining 1^st order dependency on [S]_T. Table (i)  gives the conscience of k_s(u) and ks_(c).

Figure 3: [Cr(VI)] = 6*10-4 (M), [D-galactose] = 100*10-4 (M), [HClO4] + [NaClO4] = 15*10-1 (M), [phen] = 90*10-4  (M) ,  T = 30 °C. Click here to View Figure

Dependability on [H⁺]

It is observed that the acid dependency intricates for the absenteeism of catalyst and in occupancy of catalyst paths are varied. The following findings are:

Surfactant Effects

From the plot, it has been perceived that reaction rate is retarded  with surfactant (CPC).

Acrylonitrile polymerization Test For Free Radical

In sight of free radicals was ascertained by acrylonitrile polymerization under reaction kinetics in N₂ atmosphere.

Evaluation of Activation Parameters

By applying the Eyring equation, activation enthalpy (DH^¹ ) and activation entropy (DS^¹ ), have been induced.

where  k_B = Boltzmann constant (1.38×10^-23 J K^-1),  h =  Planck constant ( 6.62×10^-34 J s^-1),  R  = molar gas constant (8.31 J mol^-1K^-1). Activation-free energy (DG^¹) and its error may be evaluated in distinction to mathematical relations:

Figure  4: Graph for calculation of activation parameter. Click here to View Figure

Kinetics aspects and mechanism of the reaction

Scheme 1 depicts the reaction mechanism for D-galactose for the phen-catalysed paths and can explain the experimental results leading to the rate laws thus :

Ligand phen be subjected to complexation with chromium’s far up labile oxidation states, resulting in Cr(III)-phen in the catalyzed path. Idleness of Cr(III) (t_2g³) inhibits entry of the catalyst into the inmost coordination domain of Cr(III), which is initiated upon the reduction of Cr(IV).  In Pre-equilibrium state the active oxidant ^{[38, 39]} is the complex (C1) formed by the rapid reaction of phen with the labile Cr(VI) center to produce the instinctive cyclic Cr(VI)-L. Over the span of [L]_T used, [phen]_T shows a primary dependency. Thus, it is pertinent to assume that the equilibrium constant for cyclic Cr(VI)-L complex (C1) is of a low magnitude. Hence, there is no kinetic affirmation for C1 composite generation. In addition to phen, there is no change in the chromic acid spectrum, thus negating any spectroscopic evidence. However, this does not obliterate the possibility of such complex formation^46–49. In oxidation-reduction reactions, cyclic form of sugar get involved.^{6, 7,3} Arguably, better exposure of hemiacetal hydroxy groups result in profound interaction with Cr(VI). Hence, it is justified to conclude that the cyclic and the acyclic forms contribute additively to the pseudo 1^st order rate constants while being in a potent equilibrium. Subsequently, The interaction of the substrate with Cr(VI)-L complex results in a ternary compound (C2) (cf. scheme-1) that undergoes redox decomposition to finally yield the organic product before passing through a cyclic transition state. The Cr(IV)-phen composite compound might later take part in more swift reactions, i.e., the Rocek mechanism.⁵⁰ DS^¹  (entropy of activation, cf. Table 1) with a large negative magnitude of the complex rate constant (k_cat) indicates a cyclic transition state. The final product is obtained when the Cr(IV)-species, caused in the rate-determining step, takes part in the forthcoming faster paces.

Figure 5 : [Cr(VI)] = 6*10-4 (M), [D-galactose] = 10*10-3 (M),  [phen] = 9*10-3 (M), [H2S04]  =  0.5(M), T = 32 °C, [CPC] = (2-16)*10-3 (M). Click here to View Figure

Scheme 1: Mechenistic aspects of Cr(VI) oxidation of D-galactose in presence of 1,10-phenanthroline Click here to View Scheme

Effect of surfactant (CPC)

CPC, is a typical cationic surface active agent, acting as an inhibitor of the catalysed paths. An incessant  diminution and, ultimately, the ease off at larger CPC concentrations was observed in k_obs(T) vs. [CPC]_T  (cf. Figure- 5) profile. It matches the observation of Cerichelli and Bunton ⁵¹ in the ferrocene oxidation using ferric salts in surfactant like CTAB (cetyltrimethyl ammonium bromide) media. Panigrahi and Sahu ⁵² reported very similar observations in acetophenone oxidation by Ce(IV) in accompanied by NDPC (N-dodecyl pyridinium chloride). Reddi and Sarada ³⁴ observed similar oxidation of aromatic azo compounds using chromic acid with anionic surfactant SDS. It was found that in the catalysed route, CPC thwarts electropositive Cr(VI)-catalyst composite compound (C1 is the agile oxidizing agent) in water phase, thereby resulting in cumulation of neutral substrate in the stern layer of micellar phase which is impotent to take part in the reaction. Thus, in catalyzed process, this reaction is primarily constrained in the water media, where substrate concentration is exhausted owing to its portioning in stern layer of micellar phase. Scheme 2 depicts the segregation of reactants between micellar and aqueous phases, where Dn appears for micelles surface active agents with ‘n’ signifying accumulation  number.

Scheme 2: Partitioning of the reactive species between the aqueous and micellar phases Click here to View scheme

Table 1: Rate constants and kinetic parameters like ∆H^≠ and∆S^≠ for D-galactose oxidation by CrIVI) with 1,10-phen catalyst in aqueous-surfactant environment.

Temp(0C)	104kobs(u)(w) a(s-1)	kcat(w)a (L mol-1s-1)	ks(c)(w) (L mol-1s-1)	ks(c)(CPC)b (L mol-1s-1)	104kH(c)(w) d (L mol-1s-1)	keff(w) (10)
22 32 40	0.50 0.85 1.50	0.0372 0.0445 0.0489	0.0372	0.0254	9.477	7.400000 5.235294 3.066667

∆H≠ (KJ/mole)	9.24
∆S≠ (J/K/mole)	-203.71

Depicts uncatalyzed path (u) ; catalzsed route (c) ; aqueous media (w) ;  value in the presence of N-cetylpyridininium chloride media (CPC).

K_{obs(u)(w )}= rate constants of uncatalysed reaction in aqueous medium.

K_obs(c)(w) = rate constants in catalysed reaction in non-surfactantphase.

K_cat(w) = slope of the plot of k_obs(c)(w) vs.  [1,10-phen] of phen catalysed reaction in water environment.

K_eff(w) = (k_obs(c)(w) – k_obs(u)(w)) / k_obs(u)(w), determined at [phen] = 10*10^-3 (M);  [Cr (VI)]=60*10^-5 (M); [D-galactose] = 1*10^-2  (M) ;  [H₂S0₄] = 5* 10^-1 (M).

[Cr (VI)] = 60*10^-5 (M) ; [D-galactose] = 1*10^-2 (M) ; [1,10 phen] = (2-12) *10^-3 (M) ; [H₂S0₄] = 5* 10^-1 (M).

[Cr (VI)] =60*10^-5 (M) ; [D-galactose] = (10-30) *10^-3 (M) ; [1,10-phen] = 40*10^-4 (M); [H₂S0₄] = 5* 10^-1 (M) ; [CPC] = 60*10^-4 (M).

[Cr (VI)] = 60*10^-5 (M) ; [D-galactose] = 1*10^-2 (M) ; [H⁺] = (25*10^-2-125*10^-2) (M).

[Cr (VI)] =60*10^-5 (M) ; [D-galactose] = 10*10^-3 (M) ; [1,10-phen] = 12*10^-3 (M) , [H⁺] = (25*10^-2 – 125*10^-2) (M).

Conclusions

Reduction of D-galactose by chromic acid in a phen-catalysed path to give the lactone as the oxidized product. The active oxidizing agent has been identified as the cationic species as the Cr(VI)-phen composite compound. This active oxidant combines with the reductant D-galactose to produce a ternary complex that undergoes 2-electron transport oxidation-reduction reactions. The reactions were executed using an aqueous micelle-infused environment. CPC is a cationic surface reagent acting as an inhibitor of the catalysed paths. An incessant diminish and, ultimately, the ease off at larger CPC concentrations has been observed. The observed micellar effects were rationalized in the aqueous-micellar phase to uphold the suggested reaction mechanism.

Acknowledgment

Thanks to S. A. Jaipuria College for using the research laboratory facility and to my colleagues Dr. Dipanwita Guha Bose, Associate Professor, and Dr. Nilasish Pal, Associate Professor, for their assistance.

Funding Sources

The author received no financial support for the research, authorship and / or publication of this article.

Conflict of Interest

The author declared no potential conflicts of interest with respect to the research, authorship and / or publication of this article.

References

1. K. K. Sen Gupta; S. Nath Basu and S. Sen Gupta. Kinetics and Mechanism of Oxidation of D-Fructose and l-Sorbose by Chromium(VI) and Vanadium(V) in Perchloric Acid Medium. Carbohydr. Res., 1981, 97 (1), 1–9. https://doi.org/https://doi.org/10.1016/S0008-6215(00)80520-0.
   CrossRef
2. L. F. Sala; S. R. Signorella; M. Rizzotto; M. I. Frascaroli and F. Gandolfo. Oxidation of L-Rhamnose and D-Mannose by Cr(VI) in Perchloric Acid. A Comparative Study. Can. J. Chem., 1992, 70 (7), 2046–2052. https://doi.org/10.1139/v92-258.
   CrossRef
3. M. Gupta; S. K. Saha and P. Banerjee. Kinetics and Mechanism of the Reduction of Dodecatungstocobaltate (III) by D-Fructose, D-Glucose, and D-Mannose: Comparison between Keto- and Aldohexoses. J. Chem. Soc. Perkin Trans. 2, 1988, No. 10, 1781–1785. https://doi.org/10.1039/P29880001781.
   CrossRef
4. Kabir-ud-Din; A. M. A. Morshed and Z. Khan. Micellar Effects on the Chromium(VI) Oxidation of d (+)-Xylose. Inorg. React. Mech., 2002, 3 (4), 255–266. https://doi.org/10.1080/1028662021000003865.
   CrossRef
5. M. Rizzotto; M. I. Frascaroli; S. Signorella and L. F. Sala. Oxidation of L-Rhamnose and d-Mannose by Chromium(VI) in Aqueous Acetic Acid. Polyhedron, 1996, 15 (9), 1517–1523. https://doi.org/https://doi.org/10.1016/0277-5387(95)00392-4.
   CrossRef
6. K. K. Sen Gupta; and S. Nath Basu. Kinetics and Mechanism of Oxidation of D-Glucose and d-Ribose by Chromium(VI) and Vanadium(V) in Perchloric Acid Medium. Carbohydr. Res., 1980, 80 (2), 223–232. https://doi.org/https://doi.org/10.1016/S0008-6215(00)84861-2.
   CrossRef
7. K. K. Sen Gupta; S. Sen Gupta and S. Nath Basu. Kinetics and Mechanism of Oxidation of Some Aldoses by Chromic Acid in Perchloric Acid Medium. Carbohydr. Res., 1979, 71 (1), 75–84. https://doi.org/https://doi.org/10.1016/S0008-6215(00)86062-0.
   CrossRef
8. A. K. Das; S. K. Mondal; D. Kar and M. Das. Micellar Effect on Chromium(VI) Oxidation of D-Glucose in the Presence and Absence of Picolinic Acid in Aqueous Media: A Kinetic Study. Bioinorg. React. Mech., 2001, 3 (1), 63–74. https://doi.org/10.1515/irm-2001-0107.
   CrossRef
9. A. K. Das; A. Roy; B. Saha; R. K. Mohanty and M. Das. Micellar Effect on the Reaction of Chromium(VI) Oxidation of D-Fructose in the Presence and Absence of Picolinic Acid in Aqueous Media: A Kinetic Study. J. Phys. Org. Chem., 2001, 14 (6), 333–342. https://doi.org/https://doi.org/10.1002/poc.374.
   CrossRef
10. S. V. Singh; O. C. Saxena and M. P. Singh. Mechanism of Copper(II) Oxidation of Reducing Sugars. I. Kinetics and Mechanism of Oxidation of D-Xylose, L-Arabinose, D-Glucose, D-Fructose, D-Mannose, D-Galactose, L-Sorbose, Lactose, Maltose, Cellobiose, and Melibiose by Copper(II) in Alkaline Medium. J. Am. Chem. Soc., 1970, 92 (3), 537–541. https://doi.org/10.1021/ja00706a020.
    CrossRef
11. A. Kumar; and R. N. Mehrotra. Kinetics of Oxidation of Aldo Sugars by Quinquevalent Vanadium Ion in Acid Medium. J. Org. Chem., 1975, 40 (9), 1248–1252. https://doi.org/10.1021/jo00897a014.
    CrossRef
12. S. Signorella; V. Daier; S. Garcı́a; R. Cargnello; J. C. González; M. Rizzotto and L. F. Sala. The Relative Ability of Aldoses and Deoxyaldoses to Reduce CrVI and CrV. A Comparative Kinetic and Mechanistic Study. Carbohydr. Res., 1999, 316 (1), 14–25. https://doi.org/https://doi.org/10.1016/S0008-6215(99)00012-9.
    CrossRef
13. S. A. Katz; and H. Salem. The Biological and Environmental Chemistry of Chromium; 1994.
14. M. Cieślak-Golonka. Toxic and Mutagenic Effects of Chromium(VI). A Review. Polyhedron, 1996, 15 (21), 3667–3689. https://doi.org/https://doi.org/10.1016/0277-5387(96)00141-6.
    CrossRef
15. R. Codd; C. T. Dillon; A. Levina and P. A. Lay. Studies on the Genotoxicity of Chromium: From the Test Tube to the Cell. Coord. Chem. Rev., 2001, 216–217, 537–582. https://doi.org/https://doi.org/10.1016/S0010-8545(00)00408-2.
    CrossRef
16. B. Saha; M. Das; R. K. Mohanty and A. K. Das. Micellar Effect on the Reaction of Chromium(VI) Oxidation of L‐Sorbose in the Presence and Absence of Picolinic Acid in Aqueous Acid Media: A Kinetic Study. J. Chinese Chem. Soc., 2004, 51 (2), 399–408. https://doi.org/10.1002/jccs.200400062.
    CrossRef
17. F. Hasan; and J. Rocek. Cooxidation of Isopropyl Alcohol and Oxalic Acid by Chromic Acid. One-Step Three-Electron Oxidation. J. Am. Chem. Soc., 1972, 94 (9), 3181–3187. https://doi.org/10.1021/ja00764a048.
    CrossRef
18. A. K. Das. Micellar Effect on the Kinetics and Mechanism of Chromium(VI) Oxidation of Organic Substrates. Coord. Chem. Rev., 2004, 248 (1), 81–99. https://doi.org/https://doi.org/10.1016/j.cct.2003.10.012.
    CrossRef
19. A. K. Das. Kinetics and Mechanism of the Chromium(VI) Oxidation of Formic Acid in the Presence of Picolinic Acid and in the Presence and Absence of Surfactants. Bioinorg. React. Mech., 1999, 1 (2), 161–168. https://doi.org/10.1515/irm-1999-0210.
    CrossRef
20. A. K. Das; S. K. Mondal; D. Kar and M. Das. Micellar Effect on the Reaction of Picolinic Acid Catalyzed Chromium(VI) Oxidation of Dimethyl Sulfoxide in Aqueous Acidic Media: A Kinetic Study. Int. J. Chem. Kinet., 2001, 33 (3), 173–181. https://doi.org/https://doi.org/10.1002/1097-4601(200103)33:3<173::AID-KIN1011>3.0.CO;2-I.
    CrossRef
21. M. T. Beck; and D. A. Durham. The Effect of EDTA on the Hydrazine-Chromium(VI) Reaction. J. Inorg. Nucl. Chem., 1971, 33 (2), 461–470. https://doi.org/https://doi.org/10.1016/0022-1902(71)80389-5.
    CrossRef
22. S. Meenakshisundaram; and R. Vinothini. Kinetics and Mechanism of Oxidation of Methionine by Chromium (VI): Edta Catalysis. Croat. Chem. acta, 2003, 76 (1), 75–80.
23. V. M. Sadagopa Ramanujam; S. Sundaram and N. Venkatasubramanian. Oxidation of Hydrazine by Cr(VI) Oxide. Kinetic and Mechanistic Studies in the Presence of Complexing Agents. Inorganica Chim. Acta, 1975, 13, 133–139. https://doi.org/https://doi.org/10.1016/S0020-1693(00)90188-9.
    CrossRef
24. B. Saha,; M. Islam, and A. K. Das,. Micellar Effects on the Reactions of Chromium(VI) Oxidation of Lactic Acid and Malic Acid in the Presence and Absence of Picolinic Acid in Aqueous Acid Media. Bioinorg. React. Mech., 2006, 6 (2), 141–149. https://doi.org/10.1515/IRM.2006.6.2.141.
    CrossRef
25. B. Saha; M. Islam and A. K. Das. Micellar Effect on the Catalytic Co-Oxidation of Dimethyl Sulfoxide and Oxalic Acid by Chromium(VI) in Aqueous Acid Media: A Kinetic Study. Prog. React. Kinet. Mech., 2005, 30 (3), 215–226. https://doi.org/10.3184/007967405779134047.
    CrossRef
26. M. Islam; B. Saha and A. K. Das. Kinetics and Mechanism of Picolinic Acid Promoted Chromic Acid Oxidation of Maleic Acid in Aqueous Micellar Media. J. Mol. Catal. A Chem., 2007, 266 (1), 21–30. https://doi.org/https://doi.org/10.1016/j.molcata.2006.10.042.
    CrossRef
27. M. Islam; and A. K. Das. Picolinic Acid Assisted Three-Electron Transfer Chromic Acid Oxidation of Dl-Mandelic Acid in Aqueous Micellar Media: A Kinetic Study. Prog. React. Kinet. Mech., 2008, 33 (3), 219–240. https://doi.org/10.3184/146867808X339296.
    CrossRef
28. R. E. Hintze; and J. Rocek. Catalysis in Oxidation Reactions. 3. The Oxalic Acid Catalyzed Chromic Acid Oxidation of Tris(1,10-Phenanthroline)Iron(II). J. Am. Chem. Soc., 1977, 99 (1), 132–137. https://doi.org/10.1021/ja00443a025.
    CrossRef
29. C. Srinivasan; S. Rajagopal and A. Chellamani. Mechanism of Picolinic-Acid-Catalysed Chromium(VI) Oxidation of Alkyl Aryl and Diphenyl Sulphides. J. Chem. Soc. Perkin Trans. 2, 1990, No. 11, 1839–1843. https://doi.org/10.1039/P29900001839.
    CrossRef
30. A. K. Das; S. K. Mondal; D. Kar and M. Das. Kinetics and Mechanism of Picolinic Acid Promoted Chromium(VI) Oxidation of Dimethyl Sulfoxide in the Presence and Absence of Surfactants. J. Chem. Res. Synopses, 1998, No. 9, 574–575. https://doi.org/10.1039/A800993G.
    CrossRef
31. F. Hasan; and J. Rocek. Three-Electron Oxidations. VI. Chromic Acid Cooxidation of Cyclobutanol and Oxalic Acid. Chromium(V) Oxidation of Cyclobutanol. J. Am. Chem. Soc., 1974, 96 (2), 534–539. https://doi.org/10.1021/ja00809a032.
    CrossRef
32. A. Granzow; A. Wilson and F. Ramirez. Stopped-Flow Kinetics of the Chromium(VI) Oxidation of Malachite Green in the Presence of Oxalic Acid. J. Am. Chem. Soc., 1974, 96 (8), 2454–2462. https://doi.org/10.1021/ja00815a026.
    CrossRef
33. P. V. S. Rao; K. S. Murty; P. S. N. Murty and R. V. S. Murty. Kinetics of Oxalic Acid-Catalyzed Oxidation of Aromatic Azo-Compounds by Chromic Acid-Catalytic Kinetic Determination of Microamounts of Oxalic-Acid. J. Indian Chem. Soc., 1979, 56 (6), 604–607.
34. N. C. Sarada; and I. Ajit Kumar Reddy. Effect of Surfactants on Oxalic Acid Catalysed Oxidation of Aromatic Azo Compounds by Chromium (VI). J. Indian Chem. Soc., 1993, 70, 35.
35. T.-Y. Lin. Kinetic Studies of Catalyzed Chromic Acid Oxidation of Propionaldehyde by Picolinic Acid. J. Chinese Chem. Soc., 1981, 28 (1), 21–28. https://doi.org/https://doi.org/10.1002/jccs.198100004.
    CrossRef
36. J. Rocek; and T. Y. Peng. Catalyzed Oxidation Reactions. 4. Picolinic Acid Catalysis of Chromic Acid Oxidations. J. Am. Chem. Soc., 1977, 99 (23), 7622–7631. https://doi.org/10.1021/ja00465a034.
    CrossRef
37. T.-Y. Lin. Kinetic Studies of Picolinic Acid Catalyzed Chromic Acid Oxidation of Cyclohexanone. J. Chinese Chem. Soc., 1981, 28 (3), 149–154. https://doi.org/https://doi.org/10.1002/jccs.198100027.
    CrossRef
38. Z. Khan; and Kabir-ud-Din. Kinetics and Mechanism of Ethylenediaminetetraacetic Acid-, 2,2′-Bipyridyl-, and 1,10-Phenanthroline-Assisted Chromium(VI) Oxidation of 2-Propanol. Transit. Met. Chem., 2002, 27 (8), 832–839. https://doi.org/10.1023/A:1021382505230.
    CrossRef
39. T. Lin; H. Zeng and C. Chuo. Kinetics of 2,2′‐Bipyridyl‐Catalyzed Oxidation of Isopropyl Alcohol with Chromic Acid. J. Chinese Chem. Soc., 1995, 42 (1), 43–49. https://doi.org/10.1002/jccs.199500008.
    CrossRef
40. R. Bayen; M. Islam; B. Saha and A. K. Das. Oxidation of D-Glucose in the Presence of 2,2′-Bipyridine by CrVI in Aqueous Micellar Media: A Kinetic Study. Carbohydr. Res., 2005, 340 (13), 2163–2170. https://doi.org/https://doi.org/10.1016/j.carres.2005.07.002.
    CrossRef
41. M. Islam; B. Saha and A. K. Das. Chromic Acid Oxidation of Hexitols in the Presence of 2,2′-Bipyridyl Catalyst in Aqueous Micellar Media: A Kinetic Study. Int. J. Chem. Kinet., 2006, 38 (9), 531–539. https://doi.org/https://doi.org/10.1002/kin.20181.
    CrossRef
42. B. Saha; M. Islam and A. K. Das. Kinetics and Mechanism of 2,2′-Bipyridine Catalysed Chromium(VI) Oxidation of Dimethyl Sulfoxide in the Presence and Absence of Surfactants†. J. Chem. Res., 2005, 2005 (7), 471–474. https://doi.org/10.3184/030823405774309050.
    CrossRef
43. L. Lyons. A Practical Guide to Data Analysis for Physical Science Students; Cambridge University Press, 1991. https://doi.org/10.1017/CBO9781139170321.
    CrossRef
44. L. Hough; J. K. N. Jones and W. H. Wadman. Quantitative Analysis of Mixtures of Sugars by the Method of Partition Chromatography. Part V. Improved Methods for the Separation and Detection of the Sugars and Their Methylated Derivatives on the Paper Chromatogram. J. Chem. Soc., 1950, 1702. https://doi.org/10.1039/jr9500001702.
    CrossRef
45. W. E. Trevelyan; D. P. Procter and J. S. Harrison. Detection of Sugars on Paper Chromatograms. Nature, 1950, 166 (4219), 444–445. https://doi.org/10.1038/166444b0.
    CrossRef
46. V. Daier; S. Signorella; M. Rizzotto; M. I. Frascaroli; C. Palopoli; C. Brondino; J. M. Salas-Peregrin and L. F. Sala. Kinetics and Mechanism of the Reduction of CrVI to CrIII by D-Ribose and 2-Deoxy-D-Ribose. Can. J. Chem., 1999, 77 (1), 57–64. https://doi.org/10.1139/v98-210.
    CrossRef
47. K. K. Sen Gupta; and S. N. Basu. Kinetics and Mechanism of Oxidation of D-Erythrose and DL-Glyceraldehyde by Chromium(VI) and Vanadium(V) in Perchloric Acid Medium. Carbohydr. Res., 1980, 86 (1), 7–16. https://doi.org/https://doi.org/10.1016/S0008-6215(00)84576-0.
    CrossRef
48. K. K. Sengupta; T. Samanta and S. N. Basu. Kinetics and Mechanism of Oxidation of Ethanol, Isopropanol and Benzyl Alcohol by Chromium(VI) in Perchloric Acid Medium. Tetrahedron, 1986, 42 (2), 681–685. https://doi.org/https://doi.org/10.1016/S0040-4020(01)87470-6.
    CrossRef
49. A. C. Chatterji; and S. K. Mukherjee. Mechanism of Chromic Acid Oxidations. Zeitschrift für Phys. Chemie, 1965, 2280 (1), 166–172. https://doi.org/10.1515/zpch-1965-22823.
    CrossRef
50. F. Hasan; and J. Roček. The Chromic Acid Oxidation of Oxalic Acid: Evidence of Chromium(IV) Oxidation. Tetrahedron, 1974, 30 (1), 21–24. https://doi.org/https://doi.org/10.1016/S0040-4020(01)97211-4.
    CrossRef
51. C. A. Bunton; and G. Cerichelli. Micellar Effects upon Electron Transfer from Ferrocenes. Int. J. Chem. Kinet., 1980, 12 (8), 519–533. https://doi.org/10.1002/kin.550120803.
    CrossRef
52. G. P. Panigrahi; and B. P. Sahu. Micellar Effect on Oxidation of Acetophenones by Cerium (Iv). J. Indian Chem. Soc., 1991, 68 (4), 239–242.