123-92-2Relevant articles and documents
Isoamyl acetate synthesis in imidazolium-based ionic liquids using packed bed enzyme microreactor
Cvjetko, Marina,Vorkapi?-Fura?, Jasna,?nidar?i?-Plazl, Polona
, p. 1344 - 1350 (2012)
The acylation of isoamyl alcohol with acetic anhydride catalyzed by immobilized Candida antarctica lipase B was studied in ionic liquids (ILs) based on quaternary imidazolium cations with alkyl, alkenyl, alkynyl, benzyl, alkoxyl or N-aminopropyl side chains. Among the tested ILs, the highest enzyme activity together with the highest isoamyl acetate yield were obtained in [C 7mmim][Tf2N]. No loss of lipase B activity was observed during one-month incubation in this hydrophobic IL without the presence of substrates. Isoamyl acetate synthesis using [C7mmim][Tf2N] as solvent was further studied in a continuously operated miniaturized enzymatic packed bed reactor at various flow rates and temperatures. Up to 92% isoamyl acetate yield could be obtained within 15 min by using 0.5 M acetic anhydride and 1.5 M isoamyl alcohol inlet concentrations at 55°C, corresponding to the volumetric productivity of 61 mmol l-1 min -1, which to the best of our knowledge is the highest reported so far for this reaction. No decrease in productivity was experienced during the subsequent runs of continuous microbioreactor operation performed within 14 consecutive days. The benefits of reactor miniaturization along with the green solvent application were therefore successfully exploited for the development of a sustainable flavour ester production.
Lipase-catalysed esterification in supercritical carbon dioxide and in hexane
Vija, Heiki,Telling, Artur,Tougu, Vello
, p. 259 - 262 (1997)
Isoamyl acetate was synthesised in high yields (>90%) via lipase catalysed acylation of the corresponding alcohol by ammonium acetate in supercritical carbon dioxide (SCCD) and by acetic acid in hexane, The esterification rate was higher in hexane. The product yield depended sharply on the reagent concentrations in hexane whereas it was nearly independent on the pressure and temperature of the SCCD.
Optimization of catalytic activity of sulfated titania for efficient synthesis of isoamyl acetate by response surface methodology
Afshar, Shahrara,Sadehvand, Maryam,Azad, Alireza,Dekamin, Mohammad G.,Jalali-Heravi, Mehdi,Mollahosseini, Afsaneh,Amani, Mansoor,Tadjarodi, Azadeh
, p. 1949 - 1957 (2015)
TiO2 nanoparticles were synthesized by sol-gel method using titanium tetraisopropoxide. Sulfate ions were introduced on the titania by impregnation method using sulfuric acid as precursor of sulfate ions. Fourier transform infrared and energy-dispersive X-ray spectroscopy, X-ray fluorescence as well as X-ray diffraction, scanning electron microscopy, and BET methods were used for the characterization of the obtained nanoparticles. The esterification of isoamyl alcohol with acetic acid was investigated to prove the catalytic activity of the TiO2 nanoparticles under solvent-free conditions. Response surface methodology was applied to optimize the effect of some parameters such as the molar ratio of acetic acid to alcohol, catalyst loading, reaction temperature, and reaction time on the yield of the isoamyl acetate. The TiO2 nanoparticles were proved to be an excellent heterogeneous catalyst for isoamyl acetate synthesis under solvent-free conditions affording a high yield of 94 % under the following optimal conditions: molar ratio of acetic acid to alcohol (1:7), catalyst loading (3.2 wt% with respect to the acetic acid), the reaction temperature (130 °C), and the reaction time (300 min). Graphical abstract: [Figure not available: see fulltext.]
Heterogeneous catalysed esterification of acetic acid with isoamyl alcohol: Kinetic studies
Teo,Saha
, p. 174 - 182 (2004)
Kinetics of heterogeneous catalyzed esterification of acetic acid with isoamyl alcohol was studied with a cation-exchange resin catalyst, Purolite CT-175, in a stirred batch reactor to synthesize a value added ester, isoamyl acetate. About 97% (wt/wt) of the catalyst particles were within the size range 600-850 μm, and the remainder were within 180-500μm. The equilibrium conversion of acetic acid increased from ～ 80% at a feed mole ratio (alcohol to acid) of 2:1 to 95% at a feed mole ratio (alcohol to acid) of 10:1. The optimum catalyst loading based on the current findings was 10% (wt/wt). The equilibrium conversion of acetic acid increased slightly with an increase in temperature and increased appreciably with an excess of isoamyl alcohol in the reacting system. CT-175 catalyst could be repeatedly used without sacrificing its catalytic activity. Langmuir-Hinshelwood-Hougen-Watson (LHHW) model gave a better representation of the kinetic behavior for all practical purposes on the reaction kinetics studied under the given conditions. According to the LHHW mechanism, acetic acid adsorbed on one catalytic center reacted with isoamyl alcohol adsorbed on another catalytic center to give isoamyl acetate and water each adsorbed on one center.
Enhanced synthesis of isoamyl acetate using an ionic liquid-alcohol biphasic system at high hydrostatic pressure
Eisenmenger, Michael J.,Reyes-De-Corcuera, Jose I.
, p. 36 - 40 (2010)
Isoamyl acetate has a banana flavor that can be considered a "natural" ingredient when synthesized using a lipase-catalyzed reaction. Production of isoamyl acetate was up to 10-fold higher with free lipase versus immobilized Candida antarctica lipase B (CALB) after 3 h at 300 MPa and 80 °C in 1-butyl-3-methylimidazolium hexafluoro-phosphate, isoamyl alcohol biphasic system. Rate of catalysis by free CALB was 15-fold greater at 500 MPa, 40 °C than at 0.1 MPa, 40 °C and 14-fold at 500 MPa, 80 °C than at 0.1 MPa, 80 °C. Activation energy of free lipase calculated between 40 and 80 °C at 0.1 MPa (55.6 ± 4.2 kJ mol-1) or 300 MPa (56.2 ± 4.6 kJ mol-1) was not significantly different. Similarly, activation volume (ΔV?) of free lipase calculated between 0.1 and 500 MPa at 40 °C (-16.1 ± 1.5 cm 3 mol-1) or 80 °C (-16.7 ± 1.4 cm3 mol-1) was not significantly different. After treatment at high pressure and upon pressure release, the free lipase was temporarily suspended in a semi-solid IL phase. This study is the first to combine the use of a room temperature ionic liquid (RTIL) and high hydrostatic pressure (HHP) for enhanced enzyme catalysis.
Novel nanostructured tin dioxide as promising carrier for Candida rugosa lipase
Guncheva, Maya,Dimitrov, Momtchil,Zhiryakova, Diana
, p. 2170 - 2177 (2011)
This is the first report on lipase immobilization on nanostructured tin dioxide. The material was applied as a support for Candida rugosa lipase. All biocatalytic characteristics obtained for this novel biocatalyst (nano-SnO 2-CRL) were compared with those for lipase immobilized on polypropylene (PP-CRL). Nano-SnO2-CRL has shown a specific activity eight times higher than that found for PP-CRL. The tin dioxide preparation preserved up to 45% of the initial lipase activity after 1 h incubation at pH 10.0, while PP-CRL was completely inactivated. The immobilization on the inorganic carrier enhanced lipase thermal stability. Upon heating for 1 h at 55 °C, nano-SnO2-CRL retained 77% active, while PP-CRL was half inactivated. The synthetic activity and the effect of several parameters on isoamyl acetate production for both biocatalysts were evaluated. Among four tested acyl donors, acetic anhydride was the most efficient for nano-SnO 2-CRL. The reaction proceeded with a high reaction rate and resulted in 88.2% yield of the target ester for 2 h. Among various solvents, n-decane proved to be the best for both catalysts. The increase in the reaction temperature from 50 °C to 60 °C enhanced the reaction rate 1.5 and 1.7 fold, for nano-SnO2-CRL and PP-CRL, respectively. A considerable decline in activity for both enzyme preparations was observed after the second esterification run due to prolonged heating and probably also to inhibition by substrates and product.
Synthesis, Characterisation, and Determination of Physical Properties of New Two-Protonic Acid Ionic Liquid and its Catalytic Application in the Esterification
Shahnavaz, Zohreh,Zaharani, Lia,Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie
, p. 165 - 172 (2020/10/26)
A new ionic liquid was synthesised, and its chemical structure was elucidated by FT-IR, 1D NMR, 2D NMR, and mass analyses. Some physical properties, thermal behaviour, and thermal stability of this ionic liquid were investigated. The formation of a two-protonic acid salt namely 4,4′-trimethylene-N,N′-dipiperidinium sulfate instead of 4,4′-trimethylene-N,N′-dipiperidinium hydrogensulfate was evidenced by NMR analyses. The catalytic activity of this ionic liquid was demonstrated in the esterification reaction of n-butanol and glacial acetic acid under different conditions. The desired acetate was obtained in 62-88 % yield without using a Dean-Stark apparatus under optimal conditions of 10 mol-% of the ionic liquid, an alcohol to glacial acetic acid mole ratio of 1.3: 1.0, a temperature of 75-100°C, and a reaction time of 4 h. α-Tocopherol (α-TCP), a highly efficient form of vitamin E, was also treated with glacial acetic acid in the presence of the ionic liquid, and O-acetyl-α-tocopherol (Ac-TCP) was obtained in 88.4 % yield. The separation of esters was conducted during workup without the utilisation of high-cost column chromatography. The residue and ionic liquid were used in subsequent runs after the extraction of desired products. The ionic liquid exhibited high catalytic activity even after five runs with no significant change in its chemical structure and catalytic efficiency.
A pronounce approach on the catalytic performance of mesoporous natural silica toward esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols
Abd El-Wahab, Mohamed M. M.,El-Gamal, Nadia O.,Goda, Mohamed N.,Said, Abd El-Aziz A.
, (2021/12/14)
Catalytic esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols in the liquid phase over unmodified natural silica catalyst has been studied. The virgin and calcined catalysts were characterized by thermal analyses (Thermogravimetry (TG) and diffrential thermal analysis (DTA)), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and N2 sorption analyses. The acidity of natural silica catalysts was investigated using isopropyl alcohol dehydration and chemisorption of pyridine and dimethyl pyridine. The results indicated that most of the acidic sites are of Br?nsted type and of intermediate strength. The effect of different parameters such as reaction time, molar ratio, catalyst dosage, and calcination temperature was studied. Natural silica catalyst exhibited excellent catalytic performance with a selectivity of 100% to acetate esters formation. The maximum yields of isoamyl, benzyl, and cinnamyl acetate esters obtained in the batch conditions were 80, 81, and 83%, respectively. Whereas on adopting a simple distillation technique, these yields were successfully improved to higher values of 97, 98, and 90%, respectively. Experimental results manifested that the reaction followed Langmuir–Hinshelwood mechanism. Finally, the catalyst could be completely recycled without loss of its activity after four cycles of the esterification reactions.
