A Novel Oxidation of Salicyl Alcohols Catalyzed by Lipase

Zhao, Ziyuan; Zhang, Liu; Li, Fengxi; Tang, Xuyong; Ma, Yuguang; Wang, Qianqian; Wang, Zhi; Zhao, Rui; Wang, Lei

doi:10.3390/catal7120354

Cited by 10 publications

(3 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, hot deformation behavior of as-cast 30Cr2Ni4MoV steel using processing maps was discussed by Zhou [12]. Grain boundary segregation and precipitation during the plastic deformation of 30Cr2Ni4MoV steel were studied [13].…”

Section: Intrduction mentioning

confidence: 99%

Evolution and Evaluation of Duplex Grain of As-cast 30Cr2Ni4MoV Steel during Heat Treatment

Zhang¹,

Liu²,

Liu³

et al. 2020

View full text Add to dashboard Cite

As the main microstructure flaw of heavy forging, duplex grain (the grain size is non-uniform) may result in producing a reject. In this paper, the influences of heat treatment temperature and isothermal holding time on the duplex grains evolutions of as-cast 30Cr2Ni4MoV steel were studied using optical microscope and scanning electron microscope aided with XRD and EDS. It is shown that the globular austenite grains appear at 750 °C and the austenite grains in the regions rich in C, Cr, Ni, and Mo are smaller than that in other regions. Duplex grains appear in the heating process. Moreover, in the isothermal heat treatment process, grains with different grain size number also developed at all of the temperatures performed in the study. But the distribution of the grains with different sizes cannot be evaluated precisely using proper method commonly used now. On the basis of analysis of the sizes of the duplex grains, a new approach for evaluating the level of the mixture of different size grains was proposed, the result obtained are consistent with the experimental results. The microstructure of 30Cr2Ni4MoV could be more uniform by increasing the temperature and extending the heat-preservation time.

show abstract

Section: Intrduction mentioning

confidence: 99%

Evolution and Evaluation of Duplex Grain of As-cast 30Cr2Ni4MoV Steel during Heat Treatment

Zhang¹,

Liu²,

Liu³

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Recently, a novel asymmetric synthesis method to prepare an enantiomerically enriched precursor of lamivudine through whole cell catalysis mediated by Klebsiella oxytoca was reported . Among numerous biocatalysts, a family of lipases are widely used in the synthesis of chiral molecules, which are known to have catalytic promiscuity showing good catalytic abilities in C–C, C–N, C–O, and C–S bond formations. − Subtilisin was also applied to the asymmetric synthesis of lamivudine. Hu et al presented a cascade addition–cyclization–acetylation reaction to prepare the enantioenriched 1,3-oxathiolane structure via a novel surfactant-treated subtilisin Carlsberg (STS)-catalyzed dynamic kinetic resolution protocol in which the racemic substrate was continuously converted to the desired target enantiomer by efficiently coupling with enzyme catalysis. , Dynamic kinetic resolution protocols were used in many complex resolution systems. ,− The stereoconfiguration of the 1,3-oxathiolane intermediate could be effectively controlled by different types of enzymes.…”

Section: Introductionmentioning

confidence: 99%

One-Pot Enzymatic Synthesis of Enantiopure 1,3-Oxathiolanes Using Trichosporon laibachii Lipase and the Kinetic Model

Zhang

Sun

Tang

et al. 2020

Org. Process Res. Dev.

View full text Add to dashboard Cite

The dynamic covalent kinetic resolution protocol was efficiently used for the synthesis of the enantiopure ((R)-5acetoxy-1,3-oxathiolan-2-yl)ethyl benzoate (P R ) from substrates 2-(phenylmethoxy)acetaldehyde (A), 1,4-dithiane-2,5-diol (B), and phenyl acetate (D) by a one-pot process with 99.6% conversion, 97.3% yield, and 96.5% ee through the combination of reversible hemithioacetal transformation and enantiomer-selective lactonization catalyzed by immobilized lipase from Trichosporon laibachii. A proposed kinetic model consisting of transformation and lactonization was developed herein for the first time, fitting the experimental data very well. It was concluded that (1) the transformation in a chemical fashion may follow a power law. (2) The enzymatic lactonization may follow a sequential mechanism with product inhibition. The reaction kinetic data reveal that phenol (P 1 ) would have strong product inhibition, while noncompetitive inhibition, product inhibition of P R , and substrate inhibition were not recognized. The model suggests that there is a common limitation of both enzyme and chemistry in the chemo-enzymatic system, and thus the amount of lipase was increased to accelerate the enzymatic lactonization and to reduce the limitation caused by the enzymatic reaction, resulting in the increase of the yield of P R significantly. The experimental results demonstrate that both the internal and external mass diffusion resistance could be negligible, and thus the kinetic model developed is the inherent kinetic one.

show abstract

“…Over the past few years, many reports have demonstrated that lipase could catalyze the in situ generation of peracids through a perhydrolysis of carboxylic acids or esters (6,7). And the in situ formed peracids have been successfully utilized in many oxidations, such as epoxidation of alkenes, Baeyer-Villiger reaction, Dakin oxidation, oxidations of amines, alcohols and sulfanyl compounds (8)(9)(10)(11)(12)(13)(14)(15). These oxidative processes are representative examples of enzyme catalytic promiscuity, which is a term used to describe an enzyme that can catalyze chemical reactions fully different than physiological ones (16).…”

Section: Introductionmentioning

confidence: 99%

Lipase-mediated epoxidation of alkenes in supercritical carbon dioxide

Zhang

Qian

Wang

et al. 2018

Green Chemistry Letters and Reviews

Self Cite

View full text Add to dashboard Cite

In this work, supercritical carbon dioxide was used as reaction media in the lipase-mediated epoxidation of alkenes for the first time. Under the optimal conditions (alkene (1 mmol), novozym 435 (15 mg), H 2 O 2 (50% aqueous solution, 1.4 mmol), n-caprylic acid (0.05 mmol), 40°C, scCO 2 (10 MPa, 25 mL)), high yields (83-98%) of epoxidation of alkenes could be obtained in a short reaction time. Furthermore, novozym 435 exhibited a satisfactory reusability in the epoxidations. Thus, this work not only presents a green and mild method of lipase-mediated epoxidation with higher yield and reaction rate than other lipase-mediated routes ever reported but also expands the application of supercritical carbon dioxide in enzyme catalytic promiscuity.

show abstract

A Novel Oxidation of Salicyl Alcohols Catalyzed by Lipase

Cited by 10 publications

References 37 publications

Evolution and Evaluation of Duplex Grain of As-cast 30Cr2Ni4MoV Steel during Heat Treatment

Evolution and Evaluation of Duplex Grain of As-cast 30Cr2Ni4MoV Steel during Heat Treatment

One-Pot Enzymatic Synthesis of Enantiopure 1,3-Oxathiolanes Using Trichosporon laibachii Lipase and the Kinetic Model

Lipase-mediated epoxidation of alkenes in supercritical carbon dioxide

Contact Info

Product

Resources

About