Catalyst grading technology for promoting the diesel hydrocracking to naphtha

This paper reports the application of multi-component hydrocracking catalyst grading technology in diesel hydrocracking system to increase naphtha,and studies the influence of catalyst systems with different number of graded beds on the reaction process of diesel hydrocracking.Three hydrocracking catalysts with different physicochemical properties as gradation components,the diesel hydrocracking reaction on catalyst systems of one-component,two-component and three-component graded beds with different loading sequences are carried out and evaluated,respectively.The catalytic mechanism of the multi-component grading system is analyzed.The results show that,with the increase of the number of grading beds,the space velocity of reaction on each catalyst increases,which can effectively control the overreaction process;along the flow direction of feedstock,the loading sequences of catalysts with acidity decreasing and pore properties increasing can satisfy the demand of different catalytic activity for the conversion of reactant with changing composition to naphtha,which has a guiding role in the conversion of feedstock to target products.Therefore,the conversion of diesel,the selectivity and yield of naphtha all increase significantly on the multi-component catalyst system.The research on the grading technology of multi-component catalysts is of great significance to the promotion and application of catalyst systems in various catalytic fields.

Next generation sequencing reveals co-existence of hereditary spherocytosis and Dubin–Johnson syndrome in a Chinese gril: A case report

BACKGROUND Hereditary spherocytosis(HS)is a hereditary disease of hemolytic anemia that occurs due to the erythrocyte membrane defects.Dubin–Johnson syndrome(DJS),which commonly results in jaundice,is a benign hereditary disorder of bilirubin clearance that occurs only rarely.The co-occurrence of HS and DJS is extremely rare.We recently diagnosed and treated a case of co-occurring HS and DJS.CASE SUMMARY A 21-year-old female patient presented to our department because of severe jaundice,severe splenomegaly,and mild anemia since birth.We eventually confirmed the diagnosis of co-occurring DJS and HS by next generation sequencing(NGS).The treatment of ursodeoxycholic acid in combination with phenobarbital successfully increased hemoglobin and reduced total bilirubin and direct bilirubin.CONCLUSION The routine application of NGS can efficiently render a definite diagnosis when inherited disorders are suspected.

Copper-Catalyzed Oxidative Dearomatization of 2-Naphthols via Etherification

Copper-catalyzed intermolecular oxidative-etherification type dearomatization reaction of 2-naphthols was developed.With air as the terminal oxidant,the reaction proceeded in excellent yields under mild conditions.In addition,the reaction between two different naphthol substrates occurred smoothly.A series of multifunctionalized β-naphthalenones,important scaffold existed widely in natural products and biologically active molecules,were synthesized efficiently.

Rh(III)-Catalyzed Enantioselective Intermolecular Aryl C—H Bond Addition to Aldehydes

The direct addition of aryl C—H bond to carbon-heteroatom double bond by transition-metal-catalyzed C—H activation has been extensively investigated in the past decade. However, the enantioselective intermolecular C—H addition to aldehyde has not yet been reported and is of significant challenge. Rh(III)-catalyzed highly enantioselective intermolecular C—H addition of aryl oxime ethers to glyoxylates is reported. Chiral mandelic acid esters were obtained in excellent yields (up to 98%) and enantioselectivity (up to 99% ee) in the presence of a chiral CpRh(III) catalyst under mild conditions. The substituents on the Cp ring and BINOL skeleton were responsible for the high enantioselectivity observed. The method displays a broad substrate scope and good functionality tolerance. These results provide not only a promising C—H addition approach but also a proof of concept for developing broader asymmetric C—H addition reactions.

Electrochemical Rhodium-Catalyzed Enantioselective C–H Annulation with Alkynes

The synergistic use of transition metal catalysis and electrochemistry is an attractive strategy for oxidative site-selective C–H functionalization since the use of stoichiometric chemical oxidants can be avoided and novel reactivity can be achieved.However,metalcatalyzed electrochemical C–H functionalization is mainly limited to arene C(sp^(2))–Hfunctionalization,and enantioselective C–H functionalization is uncommon and remains challenging.

Rhodium-Catalyzed Pyridine-Assisted C-H Arylation for the Synthesis of Planar Chiral Ferrocenes

Planar chiral ferrocenes are widely applied in organic synthesis,materials science,and medicinal chemistry,but their synthesis is not trivial.Herein,a highly efficient synthesis of planar chiral ferrocene-based pyridine derivatives via Rh(I)-catalyzed direct coupling of pyridylferrocenes with aryl halides was developed.Good yields and excellent enantioselectivity(95–>99%ee)are obtained for a wide range of substrates.The compatibility of gram-scale synthesis and relatively low catalyst loading(down to 1 mol%based on[Rh])enhance the practicality of the current method.The generated coupling products can be readily transformed into chiral ligands.Mechanistic studies suggest that the C–H bond cleavage of pyridylferrocene may be a reversible step and not the rate-determining step.Significant nonlinear effects indicate the existence of multiple metals or ligands in the active catalyst.