CXIV.—The dissociation constants of oxalacetic acid and its phenylhydrazone
نویسندگان
چکیده
منابع مشابه
Determination of the acid dissociation constants of the p-sulphonato-calix[4]arene
The acid dissociation constants of the hydroxyl groups in 25, 26, 27, 28-tetrahydroxy-5, 11, 17, 23-tetrasulphonic-calix[4]arene (SC4) were determined at 25οC by a combination of potentiometric and spectrophotometric titration method. The first and second acid dissociation constants (pKa1, pKa2) were found to be 3.19 and 12.1, which demonstrated pKa shift due to intramolecular hydrogen bonding ...
متن کاملAcidic Dissociation Constants of Folk Acid, Dihydrofolic Acid, and Methotrexate
The acidic dissociation constants in the range H,, -1.3 to pH 7 of folic acid, dihydrofolic acid, methopterin (N(lO)methylfolic acid), and methotrexate have been measured by potentiometric and spectrophotometric titrations. Assignment of these dissociations was made by comparison to model compounds, by proton magnetic resonance measurements, and by examination of associated ultraviolet absorban...
متن کاملAcidic dissociation constants of folic acid, dihydrofolic acid, and methotrexate.
The acidic dissociation constants in the range HO--1.5 to pH 7 of folic acid, dihydrofolic acid, methopterin (N(10)methylfolic acid), and methotrexate have been measured by potentiometric and spectrophotometric titrations. Assignment of these dissociations was made by comparison to model compounds, by proton magnetic resonance measurements, and by examination of associated ultraviolet absorbanc...
متن کاملThe dissociation constants of tetrahydrofolic acid.
Six dissociable groups exist in tetrahydrofolic acid in the range Ho -3.0 to pH 14. The assignments in tetrahydrofolic acid by titrimetric and spectrophotometric comparisons with model compounds, +uninobenzoylglutamic acid and 2-amino-6,7-dimethyl-5,6,7,8-tetrahydro-4-pteridinone, are as follows: acidic ionization of amide, pK’ 10.5; Ns, pK’ 4.82; y-carboxyl, pK’ 4.8; cr-carboxyl, pK’ 3.5; N1, ...
متن کاملMultiwavelength spectrophotometric determination of acid dissociation constants of ionizable drugs.
A multiwavelength spectrophotometric approach has been developed to determine acid dissociation constants (pKa values) of sparingly soluble drug compounds. UV absorption spectra of the drug solution are acquired using a versatile device based on a fiber optics dip probe, a light source and a photodiode array (PDA) detector while the PH and the ionic strength of the chemical system is manipulate...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: J. Chem. Soc., Trans.
سال: 1902
ISSN: 0368-1645
DOI: 10.1039/ct9028101158