Experimental and theoretical study on N-hydroxyphthalimide and its derivatives catalyzed aerobic oxidation of cyclohexylbenzene

The liquid phase oxidation of cyclohexylbenzene(CHB)is a new green synthetic approach to cyclohexylbenzene-1-hydroperoxide(CHBHP),a key intermediate for preparing phenol and cyclohexanone.In this work,aryl-substituted(Cl and Br)derivatives of N-hydroxyphthalimide(NHPI)were synthesized and their catalytic performances for CHB oxidation were studied.In addition,geometric optimization and transition state search were performed using DFT calculations.Both experimental and theoretical studies have proven that chloro-substitution on NHPI can significantly improve its catalytic effects on the oxidation of CHB by oxygen.Compared with NHPI,CHB conversion and selectivity of CHBHP over Cl;NHPI were increased by 10.47%and 13.24%.The strategy of aryl-substituting NHPI with halogen atoms proposed in this study would provide a potential way to the development of new NHPI-based catalysts for aerobic oxidation reactions.

Hypocotyl elongation based on HY5 transcription factor in cold resistant winter rapeseed(Brassica napus L.)

Winter rape(Brassica napus L.)is better than other edible oil crops in China,but poor cold resistance is the key factor restricting its development.Hypocotyl length was found closely related to cold tolerance.The correlation between hypocotyl length and semi-lethal low temperature was significant,and the highest correlation between hypocotyl length and LT50 of autumn sowing was 0.9557.When the hypocotyl were treated at low temperature,the cells were seriously damaged and formed cavity structures,with cell walls seriously damaged or merged into each other.The positive regulation gene of hypocotyl length in resistant line of VHTSG 10 was identified as HY5(transcription factor HY5-like)by qPCR,and bZIP transcription factor was found to be its conserved domain.Fused gene by GFP and HY5 from VHTSG 10 was transient transferred into Nicotiana benthamiana cells.Corresponding to the 35S:GFP widely distributed in plasma membrane of leaf epidermis,the fusion protein 35S:HY5-GFP was mainly distributed in nucleus.Thus we regarded BnHY5 gene is a key gene related to cold tolerance and hypocotyl length in B.napus.

Optimization of Extraction Method of Triterpenoids from Artemisia selengnesis Turcz

[Objectives]The research aimed to optimize the extraction method of triterpenoids from A. selengnesis. [Methods]The ultrasonic extraction of triterpenoids in A. selengnesis was optimized by single factor analysis( including infusion time,ethanol concentration,ultrasonic power,extraction time,and liquid-solid ratio) and response surface method. [Results]The optimum extracting process of triterpenoids was as follows: infusion time of 65 min,ethanol concentration of 80%,ultrasonic power of 275 W,extraction time of 30 min,and liquid-solid ratio of 34 m L/g. Under the optimized condition,the extraction content of triterpenoids reached( 18. 26 ± 0. 10) mg/g. [Conclusions] The optimized extraction had a good modal on practice in developing and utilization.

Fusion bonding and microstructure formation in TiB_(2)-based ceramic/metal composite materials fabricated by combustion synthesis under high gravity

The novel ceramic/metal composite materials were successfully fabricated by combustion synthesis in high gravity field.In this paper,the Ti-B_(4)C was selected as the main combustion reaction system to obtain TiB_(2)-TiC ceramic substrate,and the 1Cr18Ni9Ti stainless steel was selected as the metal substrate.It was found that the TiB_(2)-TiC/1Cr18Ni9Ti composite materials exhibited continuously graded composition and hybrid microstructure.The TiC1-x carbides and TiB_(2)platelets decreased gradually in size and volume fraction from the ceramic to stainless steel.Due to the rapid action of thermal explosion as well as the dissolution of the molten stainless steel into TiB_(2)-TiC liquid,the diffusion-controlled concentration gradient from the ceramic liquid to the alloy liquid was observed.Finally,as a result of the rapid sequent solidification of the ceramic liquid and the melt alloy surface,the laminated composite materials were achieved in multilevel,scale-span hybrid microstructure.

The influence of solute atom ordering on the deformation behavior of hexagonal close packed Ti-Al alloys

A framework of compositionally graded Ti-Al alloys was proposed to elucidate the Al alloying dependent deformation mechanism at room temperature.Slip trace analysis demonstrated low-alloyed Ti-Al model materials were plastically deformed by prismatic slip,pyramidal slip,stacking faults,and deformation twins.Increasing Al concentration promoted chemical ordering,thus suppressing the dislocation motion and deformation twinning.The mechanism behind such a kind of composition-mediated deformation physics was discussed.Our findings are expected to be applicable in the design of next-generation high-performance structural materials through the tailoring of the chemical ordering of solute atoms in substitutional solid solution.