Max), were100 90Ultrasound Mechanical agitationConversion price ( )70 60 50 40 30 20 10 0 1 2 3 4 five six 7CyclesFigure 5 Comparison among ultrasound and
Max), were100 90Ultrasound Mechanical agitationConversion price ( )70 60 50 40 30 20 ten 0 1 2 3 four 5 6 7CyclesFigure 5 Comparison among ultrasound and mechanistic agitation on reusing of Novozyme 435 for D- isoascorbyl palmitate synthesis.Cui et al. Chemistry Central Journal 2013, 7:180 http:journal.chemistrycentralcontent71Page 7 of0.4 0.y = 0.5697x 0.1117 R= 0.1[V0](hmM)0.three 0.25 0.two 0.15 0.1 0.05 0 0 0.1 0.two 0.y = 0.2924x 0.0392 R= 0.ShakingUltrasound0.0.1[B0](1mM)Figure six Lineweaver-Burk plot of reciprocal DDR2 custom synthesis initial reaction price against reciprocal palmitatic acid (B0) concentrations.were of analytical grade and obtained from Sinopharm Chemical Reagent Co., Ltd (Shanghai, China). Lipase of Novozym 435 (EC 3.1.1.3) from C. antarctica together with the catalytic activity of ten 000 PLUg (the activity of PLU refers to the millimoles of Lauric acid isopropyl acetate synthesized per minute at 60 ) had been purchased from Novozymes (Denmark). This lipase has the optimal reaction temperature of 40-70 . Methanol was of HPLCgrade bought from Tedia (Ohio, USA). All reagents were dehydrated by molecular sieve four (Shanghai planet molecular sieve Co., Ltd., Shanghai, China) and filtered using a membrane filter (0.45 m) prior to use.Ultrasound equipmentcalculated according to equation (two) as well as the LineweaverBurk plot. 1 Km 1 1 v vmax vmax The reaction was carried out in ultrasound gear (Model KQ-300DE, Ningbo, China) with 4-Lworking volume (Figure 7). The ultrasound gear was composed of water-bath, reactor and ultrasonic transducer. The ultrasound mAChR2 list energy was adjustable from 30 W to 200 W.Esterification reactionThe curve of initial velocity and palmitic acid concentration shows excellent linearity. Under the ultrasoundassisted therapy, Km and vmax values have been 7.49 mM and 25.64 mM h-1, which had been are 1.58 times and two.85 occasions of these using the mechanical shaking remedy, respectively. The comparison among ultrasound and mechanical shaking treatments was summarized in Table three. These remedy strategies resulted inside the considerable variations of reaction parameters, D-isoascorbyl palmitate productivity, and reaction price. Additional investigations will concentrate around the price assessments of energy input and improvement of large scale ultrasound assisted reaction method.Experimental SectionMaterialsD-Isoascorbic acid (purity 99 ) was supplied from Parchn Sodium Isovitamin C Co. Ltd (Dexing, Jiangxi, China). Palmitic acid, acetone, hexane and ethyl acetateThe esterification reaction under the mechanical shaking therapy was conducted as described previously [12], the reaction remedy incorporated the D-isoascorbic acid (two.five mM) and palmitic acid with a variety of molar ratios, the immobilized lipase together with the concentration from 0.five to 18.5 (ww on the substrates amount), 50 gL of molecular sieve 4 The synthesis reaction was conducted with temperature from 30 to 70 inside a temperaturecontrolled shaker at the speed of 150 rpm. As for the ultrasound remedy, the 150 mL flask was placed within the ultrasonic bath before the reaction was initiated as presented in Figure 7. The reaction answer and compositions are identical with those of the mechanical shaking treatment. The reaction temperature was controlled by adjusting the water bath temperature from 20 to 80 . The ultrasonic energy was set from 60 W to 180 W.Table 3 Comparison of D-isoascorbyl palmitate conversion overall performance in between ultrasound and mechanical shaking conditionsItems Reaction time (h) Temperature ( ) Substrate.
