ter Meulen Method for Direct Determination of Oxygen in Organic Compounds

Russell, W. Walker; Fulton, John W.

doi:10.1021/ac50086a008

Cited by 22 publications

(15 citation statements)

References 9 publications

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“…The acetals and alcohols were passed with a stream of dry hyclrogen a t -100" C. over a thoria-promoted nickel catalyst (11). Water, formecl in GO-80% ).ields, was purified by distillation, and its OI8 content determined by equilibration with carbon dioxide follo~ved by a mass-spectrometric analysis of the oxygen isotopes in the carbon dioxide (3).…”

Section: Fiydrogenolysis Of Organic Compounds and Mass-spectrometric mentioning

confidence: 99%

An Oxygen-18 Study of Acetal Formation and Hydrolysis

Stasiuk¹,

Sheppard²,

Bourns³

1956

Can. J. Chem.

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A tracer study has been made of acetal formation and hydrolysis. Benzaldehyde and la-butyraldehyde, enriched in 018, on reaction with 71-butyl and allyl alcohols, gave acetals of norn~al isotopic abundance. The label appeared in the water of condensation. Hydrolysis of benzaldehyde di-71-butyl acetal and nbutyraldehyde di-72-butyl acetal in 018 enriched water gave alcohols of normal isotopic content. r \ slight enrichment due to isotopic exchange \vas found in allyl alcohol produced by the hydrolysis of benzaldehyde tliall> l acetal. 'l'hese results establish that the reversible reaction proceeds by a fission of the aldehyde-carbon to osygen bond.'The rate-determining step in the acid-catalj-zed formation of an acetal from aldehyde and alcohol is generally assumed t o be the reaction of the second alcohol n~olecule with the conjugate acid of an interinecliate hemiacetal. In the reverse of this reaction, that is, in acetal hj-drolysis, the formation of the hemiacetal from the conjugate acicl of the acetal is collsidered to be the slo~v step (4).On the basis of the relative hydrolysis rates observed for a number of formaldehj d e acetals (12), Harnmett has suggested a unirnoleci~lar mechanism in \vhich there is formecl a carbonium ion intermediate derived from the alcohol component of the molecule (4). H!drol>sis rates, however, are much more sensitive t o structural changes in the aldeh) de component. For example, the follo\ving relative rates have been observecl i l l the l~>drolysis of acetals of pentaerj.thritol: formaldehyde, 1; acetaldeh)cle, (j X 10'; acetone, 1 X 10' (13). Ingold (5) has pointed out t h a t this kinetic effect can be understood if the carbonium ion is derived from the aldeh!de coinpoilent since then the methyl substituents \voulcl be joined direct11 to the electron cleficient carbon.This mechanism also accounts lor the ~n a r k e d l j~ greater ease of h j d r o l~ sis of acetals compared to orclinary ethers. l~lIairr~scr~pl receioed J r i~l e 14, 1 D Z .

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Section: Fiydrogenolysis Of Organic Compounds and Mass-spectrometric mentioning

confidence: 99%

An Oxygen-18 Study of Acetal Formation and Hydrolysis

Stasiuk¹,

Sheppard²,

Bourns³

1956

Can. J. Chem.

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“…The technic of determining oxygen in organic compounds by catalytic hydrogenation received a major advancement in the suggestion made by Russell and coworkers (44,73,74,75) that the nickel methanation catalyst prepared by the reduction of nickel oxide be replaced by a promoted nickel catalyst obtained by the reduction of a mixture of nickel and thorium oxides prepared in a special manner.…”

Section: The Ter Meulen Methodsmentioning

confidence: 99%

Determination of Oxygen in Organic Compounds.

Elving¹,

Ligett²

1944

Chem. Rev.

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“…The method of analysis was in general similar to that described elsewhere (6), except that the rate of hydrogen flow was reduced to 40 cc. per minute, although the catalyst temperature remained at 350°C.…”

Section: Apparatus Materials and Methodsmentioning

confidence: 99%

“…

PREVIOUS studies (2,6,7) the authors found that, when certain modifications were made, the ter Meulen method (3, 4, 5) for the direct determination of oxygen in organic compounds by catalytic hydrogenation gave satisfactory results. Thus when a very active thoria-promoted nickel catalyst was used, all oxygen was quantitatively converted to water in the analysis of compounds containing only carbon, hydrogen, and oxygen (6), and this was equally true when nitrogen (7) or small amounts of sulfur (ß) were also present.

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confidence: 99%