Preparation and Characterization of Multiester Derivative from Plant Oil as Base Stock for Biolubricants

As an alternative to petroleum-based lubricants, which are harmful to the environment in excessive amounts, a biodegradable multiester derivative(OFANE) was obtained from plant oil through a chemical modification process with four steps as follows: hydrolysis, esterification, epoxidation, and ring-opening reaction. The physical and chemical properties of OFANE, such as viscosity, acid value, pour point, evaporation loss, and oxidation induction time were measured. Results showed that OFANE had good low-temperature fluidity, thermal-oxidative stability, and tribological properties. The tribological properties of OFANE with dimeric acid additive were evaluated. The final biodegradation experiment indicated that OFANE had excellent biodegradability. The prepared OFANE showed great potential as substitute for petroleum-based lubricating base oils.

The pseudocapacitance mechanism of graphene/CoAl LDH and its derivatives:Are all the modifications beneficial?

Cobalt-Aluminum layered double hydroxide(CoAl LDH) is a hopeful electrode material due to the advantage of easy modifiability for preparing LDH-based derivatives.However,there is short of modification methods to prepare the Co-based derivatives from CoAl LDH and also short of an intuitive perspective to analyze the pseudocapacitance mechanism of CoAl LDH and its derivatives.Herein,Graphene/CoAl LDH and its derivatives including Graphene/CoS,Graphene/CoS-1,Graphene/CoOOH,Graphene/CoP were prepared by reasonably using alkali etching treatment,sulfofication and phosphorization.The specific capacitance of Graphene/CoAl LDH,Graphene/CoS,Graphene/CoS-1,Graphene/CoOOH,Graphene/CoP at1 A g^(-1) are 260.7,371.3,440.8,61.4 and 122.2 F g^(-1),especially.The pseudocapacitance mechanism of Graphene/CoAl LDH and its derivatives was analyzed.Due to the positive effect of sulfofication on the electrical conductivity of GO and cobalt sulfide,the Graphene/CoS and Graphene/CoS-1 exhibit the optimal electrochemical performance and superior rate capability.In addition,due to the repulsion effect between Graphene and OH-,the Graphene/CoAl LDH exhibits optimal cycling stability of 224.1% capacitance retention after 20000 cycles.Besides,the reason of terrible specific capacitance of Graphene/CoOOH is that the presence of H bond in interlayer of CoOOH inhibits the interaction between Co3+ and OHspecies.Hence,not all modifications will increase the specific capacitance of the electrode materials.Overall,this work provides us with a detailed analysis of the electrochemical mechanism and correlation of CoAl LDH and its derivatives from the perspective of crystal structure and composition.

Active corrosion protection of super-hydrophobic corrosion inhibitor intercalated Mg-Al layered double hydroxide coating on AZ31 magnesium alloy

Magnesium alloys,the advanced lightweight structural materials,have been successfully applied in the manufacturing field.Unfortunately,their poor corrosion resistance restrains the potential wide applications.In this work,anti-corrosion coatings were fabricated via the insitu growth of the corrosion inhibitors intercalated magnesium-aluminum layered double hydroxide(Mg-Al LDH)on AZ31 magnesium alloy and then post-sealing it by a super-hydrophobic coating.SEM,XRD,EDS,FTIR,XPS and contact angle test were conducted to analyze physical/chemical features of these coatings.Potentiodynamic polarization curves and electrochemical impedance spectroscopy were recorded to assess the anti-corrosion performance of prepared coatings.Surprisingly,Mg-Al LDH with molybdate intercalation and lauric acid modification achieves the excellent corrosion inhibition performance(99.99%)due to the multicomponent synergistic effect such as the physical protection of Mg-Al LDH,the corrosion inhibition of molybdate and super-hydrophobic properties of lauric acid.This work presents a scientific perspective and novel design philosophy to fabricate the efficient anti-corrosion coating to protect magnesium alloys and then expand their potential applications in other field.

Catalytic conversion of biomass-derived compounds to various amino acids: status and perspectives

Amino acids are important nitrogen-containing chemicals that have a variety of applications.Currently,fermentation is the widely employed method to produce amino acids;however,the products are mostly limited to natural amino acids in the L-configuration.Catalytic synthesis is an alternative approach for the synthesis of amino acids with different types and configurations,where the use of renewable biomass-based feedstocks is highly attractive.To date,several lignocellulose and triacylglycerol-derived intermediates,typicallyα-keto acids andα-hydroxyl acids,have been transformed into amino acids via the amination reaction in the presence of additional nitrogen sources(i.e.,NH3·H2O).Making full use of inherent nitrogen in biomass(i.e.,chitin and protein)to produce amino acids avoids the use of extra nitrogen sources and meets the requirements of green chemistry,which is attracting increasing attention.In this review,we summarize different chemical-catalytic systems for the transformation of biomass to amino acids.An outlook on the challenges and opportunities for more effective production of amino acids from biomass by catalytic methods is provided.

A study on integrated design conjugation profiles application analysis of scroll profiles for automobile air conditioning

The research on scroll profiles theory at present mainly is aiming at the single profile and its amelioration or parameter optimization,not aiming at the natural characteristic of the profiles equation of scroll profiles itself.Thus,the intrinsic differential equation bearing on arc-length and tangent direction angle was studied.Using the inherent differential equation and general functional theory,the conversion ideas between the expression of intrinsic differential equation and the expression in Cartesian coordinate was studied,and the condition of involutes characteristic was presented.The detailed analysis of four typical scroll profiles was given.According to the four typical scroll profiles and based on the method of Taylor series,the unified formation of general functional integration scroll profiles was established,which perfected general theory of scroll profiles increasingly.The envelope method to seek conjugation engagement profiles was studied.The unified general functional equation of scroll profiles represented the admissible function scrolls and the conjugation engagement characteristic of which was studied.The engagement condition of conjugation scroll profiles and the expression in Cartesian coordinate of conjugation scroll profiles of general functional integration scroll profiles were educed.Therefore,the restriction of inherent characteristics of single scroll profiles model is broken through.Solid modeling and machine tool path simulation can bridge the gap between design and manufacture which is essential for the design and manufacture of scroll compressors.With this method a perfect solid model can be achieved,which leads to an optimal design in terms of quality,delivery time and cost.The presentation of unified formation of general functional integration scroll profiles represents foundation factor of instinct characteristics of scroll profiles,which widens the design method of scroll compressor for automobile air conditioning.

Promoting ring-opening efficiency for suppressing toxic intermediates during photocatalytic toluene degradation via surface oxygen vacancies

Aromatic ring-opening process is well recognized as the rate-determining step for catalytic toluene degradation. In photocatalytic toluene degradation, the toxic intermediates w让h harmful effects may be generated. To clarify the precise reaction mechanism and control the toxic intermediates generation, a closely combined in situ DRIFTS and DFT calculation is utilized to address these important issues. We construct the BiOCl w让h oxygen vacancies (OVs) and reveal the structure of OVs. The defect level caused by oxygen vacancies could promote the light adsorption and charge separation, which further boosts the activation of ring-opening species and enhances the generation process of free radicals. The reaction energy barriers of four possible ring-opening processes on defective BiOCl (OVBOC) are all declined in comparison with perfect BiOCl (BOC). The existence of oxygen vacancies could smooth the ratedetermining step so the ring-opening efficiency of photocatalytic toluene degradation is highly increased. Most importantly, the methyl species would be further oxidized and tend to open the benzene-ring at benzoic acid on BOC while the ring would be broken at the benzyl alcohol on OVBOC. These results indicate that the toluene degradation pathway is shortened via the surface OVs, which enables the production of radicals with high oxidation capability for the accelerated chain scission of the ring-opening intermediates. Finally, the efficiency of the key ring-opening process could be enormously improved and toxic intermediates are effectively restrained. The present work could provide new insights into the design of high-performance photocatalysts for efficient and safe degradation of VOCs in air.

Promoted reactants activation and charge separation leading to efficient photocatalytic activity on phosphate/potassium co-functionalized carbon nitride

Photocatalytic technology has been widely adopted to address the issue of air pollution. The separation of photogenerated carriers and the activation of reactants on catalyst surface are the main factors that affect the photocatalytic efficiency. Here, the phosphate/potassium(PO_4/K) cofunctionalized carbon nitride(labeled as PO_4-CN-K) was synthesized via a one-step in situ copyrolysis of thiourea and potassium phosphate. The unique electronic structure of PO_4-CN-K could significantly improve the performance of photocatalytic NO purification. The enhanced activity of PO_4-CN-K can be attributed to the promoted activation capacity for O_2, NO and H_2O on the catalyst surface,the decreased of carriers recombination, benefiting from the co-functionalization of phosphate groups on the surface of CN and the construction of K channels between CN layers. The photocatalytic NO conversion pathway is disclosed through time-dependent in situ FT-IR, indicating that PO_4-CN-K can efficiently convert NO molecules into harmless nitrate via the NO→NO+→nitrate/nitrite routes. The research provides a novel strategy to impel the development of photocatalytic technology for efficient air purification.