The Analysis of Aliphatic Amine Mixtures; Determination of Tertiary Aliphatic Amines in the Presence of Primary and Secondary Amines and Ammonia

Abstract

Most of the methods proposed for determining tertiary aliphatic amines in the presence of primary and secondary amines have depended on the isolation and titration of unreacted tertiary amine after treatment 'of the mixture with nitrous acid.*s3 Mitchell, Hawkins and Smith4 determined primary and secondary amines in the presence of tertiary amines by acetylating the amines with a definite amount of acetic anhydride, hydrolyzing the excess acetic anhydride with a known amount of water, and determining the unused water with Karl Fischer reagent. Tertiary amine content of the sample could then be calculated from the total base value by difference.Blumrich and Elandel5 have proposed a simple method for the direct determination of tertiary amines, namely, the acetylation of primary and secondary amines and ammonia in the mixture by means of acetic anhydride, followed by potentiometric titration of unreacted tertiary amine by means of perch1ori.c acid in acetic acid. They reported application of the procedure to only one aliphatic amine mixture, composed of diethylamine and triethylamine.Additional data have now been obtained to determine the applicability of Blumrich's original procedure to other aliphatic amines, and the method has been found to be generally applicable except in the cases involving secondary amines with the nitrogen atom attached to secondary alkyl groups. With these sterically-hindered molecules, more drastic acetylation conditions are necessary. In testing several aliphatic amines, it was found that by acetylating under more vigorous conditions (reflux for one hour instead of allowing the mixture to stand three hours a t room temperature), such sterically-hindered secondary amines are quantitatively acetylated. It was also observed that under these conditions in the absence of acetic acid in the reaction mixture, certain tertiary amines are destroyed a t a significant rate. However, they undergo only slight, if any, deterioration when acetic acid is present in the acetic anhydride in amounts equivalent to the amines in the mixture. Water in the sample apparently does not interfere in the procedure, since the presence of as much as two grams of water does not prevent complete acetylation.(1) Present address: Reagents and Apparatus.-The standard 0.1 N acid is prepared by mixing the required amount of C . P. 70% perchloric acid with glacial acetic acid. The solution is standardized against anhydrous sodium carbonate (heat C. P. material at 400-450" for three t o four hours) dissolved in acetic acid and titrated potentiometrically or to the crystal violet end-point.A potentiometric titrometer of the direct-reading type, such as the Beckman Model M or the Precision-Shell,6 using glass and calomel electrodes, is convenient and very satisfactory for use in this analysis.General Procedure.--A sample weighing not more thaii 2 g. and containing no more than 1 g. of water is added t o 20 ml. of acetic anhydride containing 2 ml. of acetic acid. The mixture is allowed t o stand three hours a t room temperature....

Stability of polyethylenimine solution‐in‐liquid paraffin emulsion for preparing polyamine microspheres with potential adsorption for ionic dyes

“…A 2, 2′‐bicinchoninic acid (BCA) assay method was used to determine the quantity of the primary and secondary amine group of the microsphere . The tertiary amino groups were determined by titration with perchloric acid . The swelling ability of the microsphere was measured gravimetrically by swelling the microsphere in ultrapure water, alcohol, acetone and cyclohexane respectively at 298K and measuring the changes in their weight during swelling …”

Adsorption of ethoxylated cationic surfactants on self-assembled monolayers of alkanethiols on gold using surface plasmon resonance detection

“…The amine ethoxylates surfactants were analyzed for total basic amine before and after quaternization by potentiometric titration of the surfactant dissolved in 25 ml acetic acid by 0.1 M HClO 4 . To determine tertiary amine a sample of the surfactant was first acetylated by reflux with acetic anhydride (25 ml) and acetic acid (2 ml) for 30 min and then additional 25 ml of acetic acid was added and the sample was titrated with 0.1 M HClO 4 [16,17].…”

Acid-Base Method for Determining Mixtures of Diethylene Triamine with Hydrazine or Substituted Hydrazines.

“…This is due to the presence of two positive charges on the primary amino groups which decrease the basicity of the secondary amino group. The reactions for the DETA titration with 0.1N HC1 in isopropanol with methanol as a solvent were previously reported by Wagner et al (8) and were postulated as follows : Table I shows that the DETA titrates as a diamine in methanol. The N-0 aminoethylpiperaeine reacts also with salicylaldehyde to form N-/3 (N-salicylidene) aminoethylpiperazine.…”

“…HE REACTION of salicylaldehyde T with primary amines was first used by Wagner et al(8) to distinguish primary amines from secondary amines. Since then many investigators have used this same technique with modifications.…”