Extraction of Carboxylic Acids by Amine-Based Extractants:  Apparent Extractant Basicity According to the pH of Half-Neutralization

Abstract

This article analyzes the extraction of hydrochloric, trichloroacetic, propionic, lactic, and acetic acids by nine amine-based extractants, including Primene JMT, tris(2-ethylhexyl)amine (TEHA), and tri-n-octylamine (TOA), in various diluents. The extractants were half-loaded with the acids, and the pH values (pH hn ) of the aqueous phases were determined. The IR spectra of the organic phases were also recorded. The results were analyzed according to our theory, which was developed in a previous article, and a good correlation was found. Ion-pair formation is the main mechanism for systems in which the basicity of the amine is higher than that of the extracted acid's anion, and H-bonding of the undissociated acid becomes important only for the extraction of weak acids by weak bases. Thus, one can predict the acid form in the organic phase from the difference between the apparent basicity of the extractant on extracting HCl, pH hn(HCl,D) , and the pK a of the extracted acid.

Effects of processing on the phenolic contents, antioxidant activity and volatile profile of wheat bran tea

“…Carboxylic acids content in soak‐roasted samples were increased and nonanoic acid appeared in cellulase‐roasted samples. As aforementioned, this may due to the elevated extraction rate at higher temperature (Canari & Eyal, ).…”

“…One possible explanation is that steaming accelerated the oxidation of linoleic acid at high temperature (Zhang et al ., ). Octanoic acid was also detected in cellulase pretreated samples, likely due to the elevated extraction rate of carboxylic acid at higher temperature (Canari & Eyal, ). For the aroma compounds of ketones, 2‐butanone disappeared from all samples after the steaming process due to its low boiling point of 79.64 °C (Pubchem.ncbi.nlm.nih.gov, ).…”

Simulation and Experiment of the Homogeneously Catalyzed Production of Terpenyl Amine

“…Acetic acid in aqueous solution forms a water‐soluble complex with terpenyl amine in the organic phase. This complexation mechanism is well known in literature . Thereby, the complex was soluble in water and based on the insolubility of β ‐myrcene in water the separation of terpenyl amine and β ‐myrcene could be done by simple phase separation after the complexation reaction.…”

Membrane Extraction for Biofuel Production

“…As described in our earlier work, the organic phase consists of Alamine 336, a long chain water insoluble tri-octyl/decyl amine dissolved in octanol. Long chain aliphatic amines may be used for the extraction of carboxylic acids from dilute aqueous solutions [18][19][20][21][22][23][24][25][26][27]. Table 10.1 summarizes the various lignocellulosic biomass hydrolysates we have investigated.…”