EFFECT OF PRESSURE AND TEMPERATURE ON THE RATE OF THE ACID-CATALYZED HYDRATION OF ETHYLENE

1965 ◽  
Vol 43 (9) ◽  
pp. 2453-2456 ◽  
Author(s):  
B. T. Baliga ◽  
E. Whalley
Keyword(s):  
Transition State ◽  
Perchloric Acid ◽  
Kcal Mole ◽  
Effect Of Pressure ◽  
Energy Entropy ◽  
Acid Catalyzed ◽  
Aqueous Perchloric Acid

The rate of hydration of ethylene in dilute aqueous perchloric acid has been measured in the range 170–190 °C at 100 bars and 100 to 3 000 bars at 180 °C. The energy, entropy, and volume of activation are 33.3 ± ~1 kcal mole−1, −5.7 ± ~2.5 cal deg−1 mole−1, and − 15.5 ± ~1.5 cm3 mole−1 respectively. The volume of activation shows that at least one molecule of water is strongly bound in the transition state.

PRESSURE EFFECT AND MECHANISM IN ACID CATALYSIS: VIII. HYDROLYSIS OF ACETAMIDE AND BENZAMIDE

1961 ◽  
Vol 39 (5) ◽  
pp. 1101-1108 ◽  
Author(s):  
A. R. Osborn ◽  
T. C-W. Mak ◽  
E. Whalley
Keyword(s):  
Water Molecule ◽  
Transition State ◽  
Perchloric Acid ◽  
Acid Catalysis ◽  
Pressure Effect ◽  
Protonated Form ◽  
Dilute Acid ◽  
Additional Information ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The effect of pressures up to 3 kbar on the rate of the acid-catalyzed hydrolysis of acetamide and benzamide in both dilute and concentrated perchloric acid has been measured. The volumes of activation in dilute acid are consistent with a transition state that is not highly polar. It follows from this that if the attacking water molecule adds to the amidium ion then the reactive amidium ion is the O-protonated form, and if the attacking water molecule substitutes then the reactive amidium ion is the N-protonated form.The volume of activation for acetamide in concentrated acid provides no additional information about the mechanism. That for benzamide in concentrated acid is tentatively interpreted as favoring the O-protonated benzamidium ion as the reactive ion.

PRESSURE EFFECT AND MECHANISM IN THE ACID-CATALYZED HYDRATION OF PROPYLENE AND ISOBUTYLENE

1964 ◽  
Vol 42 (5) ◽  
pp. 1019-1026 ◽  
Author(s):  
B. T. Baliga ◽  
E. Whalley
Keyword(s):  
Molecular Structure ◽  
Strong Evidence ◽  
Pressure Effect ◽  
Transition States ◽  
Effect Of Temperature ◽  
Kcal Mole ◽  
Effect Of Pressure ◽  
Entropy Of Activation ◽  
Acid Catalyzed ◽  
Arrhenius Energy

The effect of pressure up to 3 kbar on the rate of the acid-catalyzed hydration of propylene and isobutylene has been measured. The volumes of activation are: for propylene at 100 °C−9.6 ± ~1.0 cm3 mole−1, and for isobutylene at 35 °C− 11.5 ± ~1.0 cm3 mole−1. The effect of temperature in the range 90–120 °C on the rate of hydration of propylene at 100 bar was measured. At 100 °C the Arrhenius energy is 27.1 ± ~1.0 kcal mole−1 and the entropy of activation is −5.4 ± ~2.5 cal deg−1 mole−1. Both the volumes and entropies of activation strongly indicate that a molecule of water is present in the transition states, which can therefore be represented as [olefin. H+•H2O]≠. There appears to be no strong evidence regarding the molecular structure of the transition states.

Participation of 19-substituents in electrophilic additions to 6,7-unsaturated 5α-cholestane and B-homo 5α-cholestane derivatives; A case of competition between the participation of an ambident neighboring group and external nucleophile attack

1980 ◽  
Vol 45 (2) ◽  
pp. 559-583 ◽  
Author(s):  
Pavel Kočovský ◽  
Ladislav Kohout ◽  
Václav Černý
Keyword(s):  
Perchloric Acid ◽  
Hydrobromic Acid ◽  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Neighboring Group ◽  
Acid Cleavage ◽  
Neighbouring Group Participation ◽  
Aqueous Perchloric Acid ◽  
The Difference ◽  
Electrophilic Additions

Hypobromous acid action upon the 6,7-unsaturated 19-substituted 5α-cholestans Va-Vc results in the formation of two types of products, the cyclic ethers IX as products of 5(O)n participation of the 19-substituent, and the bromohydrins X. All these compounds are formed from the 6α,7α-bromonium ions Va'-Vc'. Under the same conditions the B-homo-5α-cholestane derivatives VIIa-VIIc afforded solely the cyclic ethers XIV as products of 5(O)n participation of the 19-substituent in the cleavage of the bromonium ions VIIa'-VIIc'. Acid cleavage of the 6α,7α-epoxides VIb and VIc with aqueous perchloric acid or hydrobromic acid gave two types of products, i.e. the cyclic ethers XI and the diols XII or bromohydrines XIII. The cyclic ethers XI arise by 5(O)n participation of the 19-substituent. The B-homo-6α, 7α-epoxide VIIIc on cleavage with aqueous perchloric acid have solely the cyclic ether XVc and by treatment with hydrobromic acid VIIIc afforded the mixture of XVc, as the main product, and of the bromohydrin XVIc. Discussed is the similarity of the bromonium ion cleavage with the fission of the corresponding epoxides, the mechanism of these reactions and the difference in the behaviour of the isomeric olefins Ia-c, IIIa-c, Va-c and VIIa-c and epoxides IIb,c, IVb,c, VIb,c and VIIIb,c. The competition between ambident neighbouring group participation and external nucleophile attack is discussed as well as the dependence of the products ratio on the nucleophilicity of the attacking species.

15N N.M.R. Study of Some Palladium(II) Ammine Complexes

1988 ◽  
Vol 41 (9) ◽  
pp. 1425 ◽  
Author(s):  
TG Appleton ◽  
JR Hall ◽  
SF Ralph ◽  
CSM Thompson
Keyword(s):  
Perchloric Acid ◽  
Chemical Shifts ◽  
Free Ammonia ◽  
Silver Ion ◽  
Single Peak ◽  
Donor Atom ◽  
Ammine Complexes ◽  
Initial Product ◽  
Aqueous Perchloric Acid ◽  
Dimethylformamide Solution

Palladium(II) ammine complexes enriched in 15N give sharp singlets in their 15N n.m.r . spectra. The 15N chemical shifts depend primarily on the trans donor atom, in a qualitatively similar way to those for platinum(II) ammine complexes. A dimethylformamide solution of Pd(NH3)2Cl2 prepared in the usual way gave a single peak, consistent with the presence of only one isomer (trans). Reactions of increasing amounts of aqueous perchloric acid with Pd(NH3)42+ allowed peaks to be identified for Pd(NH3)3(H2O)2+, cis -Pd(NH3)2(H2O)22+ and Pd(NH3)(H2O)32+. The initial product of the reaction of trans-Pd(NH3)2Cl2 with silver ion is trans-Pd(NH3)2(H2O)22+, which rapidly disproportionates to Pd(NH3)3(H2O)2+ and Pd(NH3)(H2O)32+. With standing, subsequent reactions ultimately produce a solution containing predominantly cis -Pd(NH3)2(H2O)22+ in equilibrium with small amounts of the tri- and mono-ammine complexes, and free ammonia.

Perchloric acid catalyzed acylation of anisole

1976 ◽  
Vol 10 (3) ◽  
pp. 363-364
Author(s):  
B. M. Savin ◽  
S. A. Kesler
Keyword(s):  
Perchloric Acid ◽  
Acid Catalyzed
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