ChemInform Abstract: PROTONENRESONANZSPEKTROMETRISCHE UNTERSUCHUNG DER KOMPLEXBILDUNG VON 1‐HYDROPEROXY‐1‐METHYL‐CYCLOHEXAN MIT CAESIUMSTEARAT

Smirnov, P. A.; Тимофеева, Т. Н.; Syroezhko, A. M.; Potekhin, V. M.; Proskuryakov, V. A.

doi:10.1002/chin.197447100

Cited by 2 publications

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“…These results are in a good agreement with published data [7,8,12314]. The products formed in decomposition of ROOH (alcohol and water) will competitively coordinate to the catalyst, which inhibits the reaction.…”

Section: Methodssupporting

confidence: 94%

“…(8) The dependences of the shifts Dd and broadenings Dg on the concentration of alcohol or hydroperoxide, typical of the complexes studied, are shown in Figs. 13 4.…”

Section: Methodsmentioning

confidence: 99%

“…In complex formation of lithium stearate with 1-MCHP, the shift of the electron density to the oxygen atom of the OOH group in ROOH [8] can be understood with account of the electrostatic effect of Li + ion, local polarity of the carboxylate anion, and polarizability of 1-MHCP as a result of formation of H-bond. In complexation of 3d transition metal stearates, this explanation is probably incorrect since the shifts of the 1 H NMR signals of OOH are significant.…”

Section: Methodsmentioning

confidence: 99%

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Complex formation of carbonyls, carboxylates, and acetylacetonates of main-group and transition metals with hydroperoxides and alcohols

Syroezhko

Proskuryakov

2004

Russ J Appl Chem

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The thermodynamic and structural parameters of complexes formed by secondary and tertiary alcohols and hydroperoxides with carbonyls, carboxylates, and acetylacetonates of variable-valence metals were determined. The complexes of s and 3d elements with hydroperoxides have different structures.The controlling role of 3d-element carboxylates and acetylacetonates in oxidation of n-alkanes and cycloalkanes is manifested in the stage of catalytic decomposition of hydroperoxides and in competitive reactions of RO . 2 radicals with the catalyst, initial substrate, and intermediates formed in oxidation [1]. The difference in the stability and lability of the resulting complexes is the key factor responsible for the specific controlling effect of these catalysts.The aim of this study was to examine the reaction of transition metal carbonyls, carboxylates, and acetylacetonates with secondary and tertiary alcohols and hydroperoxides and to compare the catalytic activities of s and 3d elements in decomposition of tertiary hydroperoxides. EXPERIMENTALThe objects of study (ligands) were 1-methylcyclohexyl hydroperoxide (1-MCHP), cyclohexyl hydroperoxide (CHP), cyclohexanol (CH), and 1-methyl-and 4-methylcyclohexanol (1-and 4-MCH). Maingroup and transition metal [Li(I), Co(II), Cr(III), Ni(II), Cu(II)] stearates and acetylacetonates, and also metal carbonyls Cr(CO) 6 and Mo(CO) 6 were used as complexing agents.The 1 H NMR spectra of hydroperoxides in CCl 4 and n-heptane (0.62532.0 M) were recorded on RYa-2310 and Tesla BS-497 spectrometers operating at 100 MHz in the temperature range from 350oC to 22oC; the 1 H NMR spectra of alcohols were taken at 15350oC.The broadening and shifts of signals in the 1 H NMR spectra of HO and HOO groups of alcohols and hydroperoxides dissolving the catalyst suggest the presence of labile paramagnetic complexes (Figs. 133). The position and linewidth of the NMR signals of hydroperoxide and alcohol molecules in complexes Fig. 1. Chemical shift d of HO and HOO groups in the 1 H NMR spectra of alcohols and hydroperoxides vs. their concentrations [ROH] and [ROOH] in heptane at (1, 1`) 320, (2, 2`, 4, 4`) 310, and (3, 3`) 23oC. Group: (1, 1`, 2, 2`) OOH in 1-MCHP, (3, 3`) OH in 1-MCH, and (4, 4`) OOH in CHP;(1`3 4`) in the presence of 2 0 10 !3 M Mo(CO) 6 . Fig. 2. Chemical shift d of the HOO group in the 1 H NMR spectra of CHP vs. its concentration [ROOH] in heptane at -20oC (1) in the absence of a catalyst and in the presence of 2 0 10 !2 M (2) Mo(CO) 6 and (3) Co(acac) 2 .

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Section: Methodssupporting

confidence: 94%

“…(8) The dependences of the shifts Dd and broadenings Dg on the concentration of alcohol or hydroperoxide, typical of the complexes studied, are shown in Figs. 13 4.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Complex formation of carbonyls, carboxylates, and acetylacetonates of main-group and transition metals with hydroperoxides and alcohols

Syroezhko

Proskuryakov

2004

Russ J Appl Chem

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“…Partial reaction orders with respect to the initial components in catalytic decomposition of CHP field stabilization energy CFSE = 0 [10]). Theoretically, two maxima should be observed in the case of octahedral complexes for d 4 …”

Section: Methodsmentioning

confidence: 95%

“…As shown previously [4,5], s-and 3d-metal carboxylates form with MCHP complexes ML n 0 mROOH (n, m = 1, 2). This is due to the fact that intermolecular hydrogen bonds in the complexes of s elements and the coordination bond between 3d metals and the a-O atom of hydroperoxide are stronger than the hydrogen bonds in peroxide self-associates.…”

mentioning

confidence: 85%

Kinetic features of catalytic decomposition of cyclohexyl hydroperoxide and 1-methylcyclohexyl hydroperoxide

Syroezhko

Begak

2004

Russ J Appl Chem

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Catalytic decomposition of cyclohexyl and 1-methylcyclohexyl peroxides in the presence of 3d-metal acetylacetonates was studied.A cyclohexanol3cyclohexanone mixture is commercially produced on a large scale by oxidation of cyclohexane with atmospheric oxygen on a cobalt catalyst [1]. Cyclohexyl hydroperoxide (CHP, ROOH) is formed in the first step of this process. Kinetic features of the oxidation and the composition of the oxidation products are mainly determined by the course of catalytic decomposition of this intermediate. Previously, we have shown that the selectivity of cyclohexanone formation in the presence of chromiumcontaining catalysts is higher than that in the presence of industrial cobalt-containing catalysts [2].The oxidation of methylcyclohexane depends on the catalyst present in the system. The reaction yields either a tertiary alcohol (1-methylcyclohexanol) or a mixture of methylcyclohexanols and methylcyclohexanones, formed by reaction of the secondary C3H bonds with oxygen and peroxy radicals [3]. In the latter case, the reaction kinetics and composition of the oxidation products are determined by the course of transformation of tertiary 1-methylcyclohexyl hydroperoxide (MCHP, ROOH) into secondary methylcyclohexyl hydroperoxides.In this study, we examined the catalytic decomposition of CHP and MCHP in the presence of 3d-metal compounds.As shown previously [4, 5], s-and 3d-metal carboxylates form with MCHP complexes ML n 0 mROOH (n, m = 1, 2). This is due to the fact that intermolecular hydrogen bonds in the complexes of s elements and the coordination bond between 3d metals and the a-O atom of hydroperoxide are stronger than the hydrogen bonds in peroxide self-associates. These complexes catalyze decomposition of the hydroperoxide into radicals and molecular products. The catalytic activity of s-metal carboxylates [e.g., stearates (St)] in MCHP decomposition decreases with a decrease in the cation radius in the following order: CsSt > BaSt 2 > NaSt~Na 1 pel > CaSt 2 > LiSt [6]. EXPERIMENTALCyclohexyl hydroperoxide was prepared via intermediate trialkyl borates [7] at 378oC, which were oxidized with H 2 O 2 . MCHP was prepared by the procedure described in [8]. The content of the available oxygen in the hydroperoxides was 100%.3d-Metal acetylacetonates were prepared by the procedure described in [9].Decomposition of CHP and MCHP at 853105oC in the presence of catalysts listed in Table 1 was studied in decane and methylcyclohexane solutions, respectively. The catalyst concentration ranged from 3 0 10 !5 to 3 0 10 !4 and from 6 0 10 !4 to 8.8 0 10 !3 M; and the concentration of hydroperoxides, from 0.01 to 0.1 M. The first concentration range of the catalysts was chosen so as to minimize their association at 853105oC.The representative kinetic curves of overall CHP decomposition are shown in Fig. 1. The fast decomposition in the first steps decelerates with time owing to catalyst deactivation. The limiting degrees of CHP decomposition are determined by the nature and con-ÄÄÄÄÄÄÄÄÄÄÄ 1 Na pelargona...

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ChemInform Abstract: PROTONENRESONANZSPEKTROMETRISCHE UNTERSUCHUNG DER KOMPLEXBILDUNG VON 1‐HYDROPEROXY‐1‐METHYL‐CYCLOHEXAN MIT CAESIUMSTEARAT

Cited by 2 publications

References 0 publications

Complex formation of carbonyls, carboxylates, and acetylacetonates of main-group and transition metals with hydroperoxides and alcohols

Complex formation of carbonyls, carboxylates, and acetylacetonates of main-group and transition metals with hydroperoxides and alcohols

Kinetic features of catalytic decomposition of cyclohexyl hydroperoxide and 1-methylcyclohexyl hydroperoxide

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