A Novel SN1 Displacement: The Reaction of Tertiary Amines with Acetic Anhydride

1971 ◽  
Vol 49 (20) ◽  
pp. 3348-3351 ◽  
Author(s):  
R. P. Mariella ◽  
K. H. Brown
Keyword(s):  
Acetic Anhydride ◽  
Experimental Results ◽  
Methyl Ethyl ◽  
Tertiary Amines

The action of actic anhydride on tertiary amines at reflux may cause the displacement of one of the R groups from the amine. The groups which are displaced are benzyl, t-butyl, benzhydryl, trityl, and cinnamyl; the groups which are not displaced are methyl, ethyl, n-butyl, phenyl, α-naphthyl, iso-propyl, allyl, and propargyl. An SN1 mechanism with special steric requirements is consistent with the experimental results.

Comment: Concerning the Cleavage of Tertiary Amines With Acetic Anhydride

1973 ◽  
Vol 51 (13) ◽  
pp. 2177-2179 ◽  
Author(s):  
R. P. Mariella ◽  
K. H. Brown
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Methyl Acetate ◽  
Tertiary Amines

The failure of methyl-substituted tertiary amines to yield methyl acetate on cleavage by acetic anhydride indicates that the mechanism proposed by Gol'dfarb and Belen'kii cannot be correct. The results of cleavage of cinnamyldimethylamine are offered as support for the mechanism proposed by Mariella and Brown. Catalysis by acetic acid is not considered to be important.

Comment: Concerning the Paper of R. P. Mariella and K. H. Brown "A Novel SN1 Displacement: The Reaction of Tertiary Amines with Acetic Anhydride"

1973 ◽  
Vol 51 (13) ◽  
pp. 2174-2176 ◽  
Author(s):  
Ya. L. Gol'dfarb ◽  
L. I. Belen'kii
Keyword(s):  
Acetic Anhydride ◽  
Similar Data ◽  
Tertiary Amines

The remarks on the paper of Mariella and Brown (1) concern three points: (1) some similar data from the literature were not mentioned; (2) the mechanism proposed does not take into account the possibility of catalysis of the reaction; and (3) the interpretation of the process as SN1 displacement is not compatible with known data.

THE HYDROLYSIS OF ACETIC ANHYDRIDE IN WATER AND IN THE SYSTEM WATER: METHYL ETHYL KETONE

1950 ◽  
Vol 28b (11) ◽  
pp. 663-670
Author(s):  
E. N. Banks ◽  
A. E. Marshall ◽  
R. W. Vollett ◽  
R. R. McLaughlin
Keyword(s):  
Acetic Anhydride ◽  
Methyl Ethyl Ketone ◽  
Catalytic Effect ◽  
Methyl Ethyl ◽  
Initial Concentration ◽  
Velocity Constant ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Order Rate Equation ◽  
System Water

The rate of hydrolysis of acetic anhydride at 25 °C. in water (I), in solutions of methyl ethyl ketone (MEK) in water (II), and in solutions of water in MEK (III) have been studied. In I the observation of previous investigators that the velocity constant varies linearly with the initial concentration of acetic anhydride, but for any given initial concentration of acetic anhydride the reaction is pseudomonomolecular, was confirmed and extended. In II the velocity constant is lower than in I and decreases linearly with increasing concentration of MEK, but, again, the reaction is pseudomonomolecular for any given initial concentration of acetic anhydride. An equation and a nomogram that relate the velocity constant to the initial concentration of acetic anhydride, MEK, and water are presented. In III the second-order rate equation must be modified to compensate for the presumed catalytic effect of the hydrogen ion produced by hydrolysis.

Dipole moments of substituted chloroformates in dilute benzene solutions

1967 ◽  
Vol 45 (24) ◽  
pp. 3177-3179 ◽  
Author(s):  
E. Bock ◽  
D. Iwacha
Keyword(s):  
Chlorine Atom ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Experimental Results ◽  
Methyl Ethyl ◽  
Hydrocarbon Group

The dipole moments of methyl, ethyl, n-propyl, n-butyl, amyl, and phenyl chloroformate as well as n-butyl formate in dilute benzene solution at 25 °C were determined. The experimental results suggest that the configuration of the chloro-esters differs from the configuration of the unchloroinated esters, viz. the ester hydrocarbon group and the chlorine atom are cis to each other.

Electric moments and conformation of substituted fluoroformates in benzene solutions

1968 ◽  
Vol 46 (10) ◽  
pp. 1645-1648 ◽  
Author(s):  
E. Bock ◽  
D. Iwacha ◽  
H. Hutton ◽  
A. Queen
Keyword(s):  
Dipole Moment ◽  
Long Range ◽  
Fluorine Atom ◽  
Dipole Moments ◽  
Experimental Results ◽  
Spin Coupling ◽  
Coupling Mechanism ◽  
Methyl Ethyl ◽  
Hydrocarbon Group ◽  
Spin Spin Coupling

The dipole moments of methyl-, ethyl-, n-propyl-, n-butyl-, n-amyl-, and phenyl-fluoroformate were determined in dilute benzene solutions at 25 °C. The experimental results suggest that the conformation of the fiuoro-esters is similar to the conformation of the chloro-esters and differs from the conformation of the normal esters; viz. the ester hydrocarbon group and the fluorine atom are cis to each other. Results of fluorine and proton n.m.r. measurements on these molecules support the conclusions based on the dipole moment data if a "through-space" coupling mechanism is assumed for the long range spin–spin coupling JH–F1−5.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

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