Synthesis of n-Butyl Lactate by Transition-Metal-Substituted Phosphotungstic Acid Salt

Abstract

Fatty acid ester perfume occupied an important position in food industry. The characteristics of them were variety, easy synthesis and low price. They were widely used in daily flavor, edible flavor and industrial flavor. POMs were a kind of stong acid bifunctional mild environment-friendly catalysts, their drawback was excellent solubility and could not be reused. Here, series of transition-metal-substituted phosphotungstate K 6 [PW 11 O 39 M Ⅱ (H 2 O)] (M = Cu, Co, Ni) Lewis acid heterogeneous phase catalysts based on mono-lacunary-Keggin type K 7 [PW 11 O 39 ] were prepared by stereoselect-eve method, K 6 [PW 11 O 39 M Ⅱ (H 2 O)] (M = Cu, Co, Ni) were abbreviated as PW 11 M Ⅱ (H 2 O) (M = Cu, Co, Ni). They were characterized by FT-IR, PXRD and element analysis. The coordinating water of transition metal was Lewis acid catalytic sites after activated. When mole ratio of butanol and lactic acid was 2: 1, amount of PW 11 M Ⅱ (H 2 O) (M = Cu, Co, Ni) was 0.125 g, volume of cyclohexane was 15 mL, the reaction temperature was 105°C, reaction time was 2 h, conversion rate of n-butyl lactate were in order: 85.9%, 79.6%, 66.3%. Activity of PW 11 X (X = Cu, Co, Ni) had no obvious changes after three times recycling. In addition, magnetic studies indicate that antiferromagnetic interactions exist in the three compounds.

Property Characterization and Mechanism Analysis of Polyoxometalates-Functionalized PVDF Membranes by Electrochemical Impedance Spectroscopy

“…(3-aminopropyl)trimethoxysilane (APTMS) purchased from Macklin, and nitric acid and iso-propyl alcohol (IPA) from Sinopharm Chemical were also used in the modification process. K 4 [PW 11 O 39 Co(H 2 O)] (PWCo) was synthesized according to the literature [ 35 , 36 ]. All reagents used to fabricate the membrane substrates and PWCo are of analytical reagent (AR) grade and used without further purification.…”