Ionization constants of benzoic acid from 25 to 250�C and to 2000 bar

1981 ◽  
Vol 10 (7) ◽  
pp. 437-450 ◽  
Author(s):  
A. J. Read
Keyword(s):  
Benzoic Acid ◽  
Ionization Constants

THE IONIZATION CONSTANTS OF p-NITROPHENYLACETIC AND PHENYLMALONIC ACIDS

1933 ◽  
Vol 8 (5) ◽  
pp. 447-449 ◽  
Author(s):  
Steward Basterfield ◽  
James W. Tomecko
Keyword(s):  
Benzoic Acid ◽  
Nitro Group ◽  
Malonic Acid ◽  
Phenylacetic Acid ◽  
Ionization Constants ◽  
Side Chain ◽  
Cooh Group ◽  
Conductivity Data ◽  
Nitrobenzoic Acid ◽  
Phenylmalonic Acid

The ionization constants of p-nitrophenylacetic and phenylmalonic acids have been determined from conductivity data. The value of K for p-nitrophenylacetic acid at 25 °C. is 1.04 × 10−4, about twice that of phenylacetic acid. The nitro group in the nucleus has not as powerful an effect on the ionization when the COOH group is in the side chain as it has when both nitro group and COOH are in the nucleus. K for p-nitrobenzoic acid is six times as great as K for benzoic acid. K for phenylmalonic acid is 2. 77 × 10−3 as compared with 1.6 × 10−3 for malonic acid.

The ionization constants of p-Aminobenzoic Acid in Aqueous solution at 25°C

1957 ◽  
Vol 10 (2) ◽  
pp. 128 ◽  
Author(s):  
RA Robinson ◽  
AI Biggs
Keyword(s):  
Aqueous Solution ◽  
Benzoic Acid ◽  
Ionization Constants ◽  
Aminobenzoic Acid ◽  
Zwitterion Formation

The ionization constants of benzoic acid and of four esters of p-aminobenzoic acid, as well as the two ionization constants of p-aminobenzoic acid itself, have been deter- mined by spectrophotometric measurements. The extent of zwitterion formation in p-aminobenzoic acid is discussed.

Ionization constants of benzoic and mononitrobenzoic acids in formamide

1972 ◽  
Vol 25 (5) ◽  
pp. 941 ◽  
Author(s):  
UN Dash ◽  
B Nayak
Keyword(s):  
Benzoic Acid ◽  
Ionization Constants ◽  
Weak Acids ◽  
General Behaviour ◽  
Nitrobenzoic Acid

The ionization constants of benzoic acid and of three mononitrobenzoic acids, at 25� in formamide, have been determined from the measurements of the electro-motive forces of the cells Pt,H2/HA(m1),KA(m2)KCl(m3)AgCl-Ag The values of the ionization constants for benzoic acid, o-nitrobenzoic acid, m-nitro-benzoio acid, and p-nitrobenzoic acid thus calculated from e.m.f. data are 4.37 x 10-7, 3.89 x 10-5, 3.98 x 10-6 and 1.32 x 10-6, respectively. These values are smaller than those in water, and are in agreement with a general behaviour exhibited by weak acids in solvents of this class.

Thermodynamics of Ionization of Benzoic Acid and Substituted Benzoic Acids in Relation to the Hammett Equation

1974 ◽  
Vol 52 (16) ◽  
pp. 2906-2911 ◽  
Author(s):  
Takeki Matsui ◽  
Hon Chung Ko ◽  
Loren G. Hepler
Keyword(s):  
Benzoic Acid ◽  
Ionization Constants ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
Good Linear ◽  
Calorimetric Measurements ◽  
Linear Relationships ◽  
Best Value ◽  
Substituted Benzoic Acids ◽  
Thermodynamics Of Ionization

We have made both ampoule and titration calorimetric measurements leading to ΔH0 of ionization of aqueous benzoic acid at 298 K, and have considered our results in relation to those from several earlier investigations in an effort to select the "best" value for this important quantity. We have also made calorimetric measurements leading to ΔH0 values for ionization of several substituted benzoic acids, and have selected "best" ΔH0 values for 15 meta- and para-substituted benzoic acids. It is found that there are good linear relationships between ΔG0, ΔH0, and ΔS0 values for most of these substituted benzoic acids. It is also found that the Hammett equation accounts well for ionization constants over the temperature range 278–318 K for all of these acids and accounts very well for ionization constants of those acids with positive σ substituent parameters.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

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