Efficient hydrogenolysis of fructose to 1,2-propanediol over bifunctional Ru-WO_(x)-MgO_(y) catalysts under mild reaction conditions via enhancing the chemoselective cleavage of C-C bonds

Selective conversion of fructose to 1,2-propanediol(1,2-PDO)is considered as a sustainable and cost-effective alternative to petroleum-based processes,however,this approach still faces challenges associated with low efficiency and harsh reaction conditions.Here,we have successfully synthesized a novel bifunctional Ru-WO_(x)-MgO_(y) catalyst through a facile'one-pot'solvothermal method.Remarkably,this catalyst exhibits exceptional catalytic performances in the conversion of fructose to 1,2-PDO under mild reaction conditions.The yield of 1,2-PDO is up to 56.2%at 140°C for 4 h under an ultra-low hydrogen pressure of only 0.2 MPa,surpassing the reported results in recent literature(below 51%).Comprehensive characterizations and density functional theory(DFT)calculations reveal that the presence of oxygen vacancies in the Ru-WO_(x)-MgO_(y) catalyst,serving as active acidic sites,facilitates the chemoselective cleavage of C-C bonds in fructose,which leads to the generation of active intermediates and ultimately resulted in the high yield of 1,2-PDO.

Cu,N codoped carbon nanosheets encapsulating ultrasmall Cu nanoparticles for enhancing selective 1,2-propanediol oxidation

In the selective oxidation of biomass-based 1,2-propanediol(PDO)with oxygen as the terminal oxidant,it is challenging to improve the lactic acid(LA)selectivity for nonnoble metal nanoparticles(NPs)due to their limited oxygen reduction rate and easy C-C cleavage.Given the high economic feasibility of nonnoble metals,i.e.,Cu,in this work,copper and nitrogen codoped porous carbon nanosheets encapsulating ultrafine Cu nanoparticles(Cu@Cu-N-C)were developed to realize highly selective of PDO oxidation to LA.The carbon-encapsulated ultrasmall Cu^(0)NPs in Cu@Cu-N-C have high PDO dehydrogenation activity while N-coordinated Cu(Cu-N)sites are responsible for the high oxygen reduction efficacy.Therefore,the performance of catalytic PDO conversion to LA is optimized by a proposed pathway of PDO→hydroxylacetone→lactaldehyde→LA.Specifically,the enhanced LA selectivity is 88.5%,and the PDO conversion is up to 75.1%in an O_(2)-pressurized reaction system(1.0 MPa O_(2)),superior to other Cu-based catalysts,while in a milder nonpressurized system(O_(2)flow rate of 100 mL min-1),a remarkable LA selectivity(94.2%)is obtained with 39.8%PDO conversion,2.2 times higher than that of supported Au nanoparticles(1%Au/C).Moreover,carbon encapsulation offers Cu@Cu-N-C with strong leaching resistance for better recycling.

Na_2CO_3-ZnO半熔融—EBT-1,2-丙二醇光度法测定高岭土中微量镁

本文建立了对高岭土中镁含量测定的Na2CO3+ZnO半熔融—EBT-1,2-丙二醇水溶液光度法。试样与碱性熔剂半熔融,熔块用水浸取后的酸性溶液中,用钨酸钠消除Ca2+、三乙醇胺(TEA)-四乙烯五胺(TEPA)掩蔽Al3+、Fe3+等干扰离子后,在pH值10.5的氨性缓冲溶液中,镁与EBT-1,2-丙二醇生成可溶于水的酒红色络合物,在分光光度计波长为520nm处测定其吸光度。结果表明,改进后的本法,操作简单、测定快捷、准确度高,测定结果的相对标准偏差(RSD)为2.44%,加标回收率(R)在97.5%～100.6%之间。

EBT-1,2-丙二醇光度法测定食品中微量镁研究

建立了EBT-1,2-丙二醇水溶液光度法准确测定食品中镁含量的新方法。试样用HNO3-HClO4湿消化,并用钨酸钠消除Ca2+、三乙醇胺-四乙烯五胺混合掩蔽剂掩蔽Te3+、Al3+等干扰离子后,在pH10.5的氨性缓冲溶液中,Mg2+与EBT生成可溶于水的酒红色络合物,在分光光度计波长为520nm处测定其吸光度。测定结果的相对标准偏差小于1.0%,加标回收率在95.4%～102.4%之间。结果表明,改进后的方法操作简便、测定快捷、准确度高、干扰小,测定结果与国家标准方法相符,相对偏差小于2.0%。

Catalytic synthesis of cyclohexanone 1,2-propanediol ketal with H_4SiW_(12)O_(40)/PAn

A new environmental friendly catalyst, H_4SiW_(12)O_(40)/PAn was prepared andidentified by means of FT-IR, XRD and TG/DTA. Cyclohexanone 1,2-propanediol ketal was synthesizedfrom cyclohexanone and 1,2-propanediol in the presence of H_4SiW_(12)O_(40)/PAn The factorsinfluencing tlie synthesis were discussed and the best conditions were found out. The optimumconditions are: molar ratio of cyclohexanone to 1,2-propanediol is 1:1.4, the quantity of catalystis equal to 1.0 percent of feed stocks, and the reaction time is 40 min. H_4SiW_(12)O_(40)/PAn is anexcellent catalyst for synthesizing cyclohexanone 1,2-propanediol ketal and its yield can reachover 96.5 percent.

Synthesis of propylene carbonate from urea and 1,2-propanediol

The production of propylene carbonate （PC） from urea and 1,2-propanediol （PG） was investigated in a batch process. The catalytic performances of zinc chloride and magnesium chloride were investigated for this reaction system. The influences of various operation conditions on the PC yield were explored. In this work, MgCl2 and ZnCl2 showed the excellent catalytic activity toward PC synthesis, and the yields of propylene carbonate reached 96.5% and 92.4%, respectively. The optimum reaction conditions were as follows： ethanol/urea molar ratio of 4, catalyst concentration of 1.5%, reaction temperature of 160 ℃, reaction time of 3 h, respectively. The route from urea and 1,2-propanediol shows advantages, such as mild reaction condition and safe operation. The catalytic system is environmentally benign.

Interaction between Pd and Cu nanoparticles in bimetallic CuPdx nanoparticles and its impact on oxidation of 1,2-propanediol to aliphatic acids

Bimetallic CuPdx nanoparticles synthesized by the wet chemical reduction method were used as the catalysts in the catalytic oxidation of 1,2-propanediol with gaseous oxygen to aliphatic acids.The palladium and copper nanoparticles in the bimetallic CuP dxnanoparticles had an alloying trend.The catalytic activity of the palladium nanoparticles in the bimetallic CuP dxnanoparticles was enhanced by the interaction between the palladium and copper nanoparticles.When the bimetallic CuPd7 nanoparticles catalyzed the oxidation of 1,2-propanediol in an alkaline aqueous solution at 100℃for 3h,lactic,formic,and acetic acids were dominantly produced with the total selectivity of above 99%at the 1,2-propanediol conversion of 85.9%.The simulation of the reaction kinetic equation on the CuPd7 catalyst showed that the reaction activation energy was 29.4kJ·mol^-1,indicating that the bimetallic CuPd7 nanoparticles had a high catalytic activity in the oxidation reaction between 1,2-propanediol and gaseous oxygen.

Detection and Analysis of 1,2-propanediol Content in Whole-crop Silage Corn

[ Objective ] The paper was to investigate the content of 1,2-propanediol in silage feed. [ Method ] Whole-crop corn was stored in laboratory bag silos and outdoor bunker silos. Bag silos were stored for 3, 7, 14, 28, 56 and 120 d, respectively, and fermentation products were analyzed after opening; the fermentation products, which were from three 500 t above-ground outdoor bunker silos stored for 120 d, were detected. Eight sampling points were selected for each bunker silo. [ Result] No 1,2-propanediol was detected out in laboratory bag silos, and lactic acid was dominant in fermentation products. The acetic acid content significantly increased （ P 〈 0.05 ） with the extension of storage time, whereas the acetic acid content was kept below one-third of the lactic acid content ; 1,2-propanediol and a small amount of 1-propanol were detected out in three bunker silos, and lactic acid was dominant in fermentation products, whereas the content of acetic acid was slightly lower than that of lactic acid. The differences in fermentation products from different silos and different sites in silos presented heterogeneity; except to propanediol, lactic acid bacteria and yeast, there was no significant difference in fermentation products at the top and bottom layers of silos （ P 〉0.05 ） ; there were significant differences in contents of lactic acid, acetic acid, 1,2-propanediol, and yeast between the outer and inner parts of silos （P 〈 0.05 ） ; except to pH values and acetic acid, there were significant differences in fermentation products between hunker silos （P 〈0. 05）. [ Conclusion] No 1,2-propanediol is detected out in laboratory bag silos due to relatively simple fermentation products. However, 1,2-propanediol can be detected in the bunker silos due to complex outdoor environment for silage, and the microorganisms producing 1,2-propanediol exist in silos.

Au/Mg(OH)_2:Highly efficient for selective oxidation of 1,2-propanediol to lactic acid with molecular oxygen

The catalytic oxidation of biomass-derived polyhydroxyl compounds provides an efficient and green route for biomass resource utility.Gold nanocrystals supported on Mg(OH)2 were synthesized by sol-immobilization method,characterized by XRD,TEM,UV-vis DRS,and tested in the selective oxidation of 1,2-propanediol to lactic acid.The gold particle size and the ratio of Au to 1,2-propanediol strongly influenced the catalytic activity.Over Au/Mg(OH)2 with the majority of gold particles concentrated in 14-18 nm,excellent catalytic performance with 94.4% conversion and 89.3% selectivity to lactic acid has been achieved under 0.3 MPa O2 at 60°C for 6 h.

Asymmetric synthesis of L-carnitine from (R)-3-chloro-1,2-propanediol

A practical chemical synthesis of L-camitine （1） has been accomplished from （R）-3-chloro-1,2-propanediol （（R）-4）, which is a main by-product originated from （R,R）-Salen Co（III） catalyzed hydrolytic kinetic resolution （HKR） of （±）-epichlorohydrin. （R）-4 was utilized as a chiral starting material to prepare the key intermediate cyclic sulfite （（R）-S）. The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of bioactive compounds.

Robust CoAl Alloy： Highly Active, Reusable and Green Catalyst in the Hydrogenolysis of Glycerol

CoAl alloy catalyst is found, for the first time, to be highly active, selective and reusable for the synthesis of diols via the hydrogenolysis of glycerol under mild conditions. The products and the catalyst could be self-separated from the reaction system through a simple reactor.

Derivation of Oridonin with Bioreduction-Responsive Disulfide Bond

A novel oridonin derivative substituted with 3-((2,3-dihydroxypropyl)dithio)-propionyl group at 14-O position was synthesized through a two-step procedure:Esterification of oridonin with 3-(2-pyridyldithio)propanoic acid and the subsequent thiol-disulfide exchange reaction with 3-mercapto-1,2-propanediol.The bioreduction-responsive di-sulfide bond in the compound leads to high leaving ability of the 14-O acyl moiety when treated with glutathione as monitored by reverse phase high-performance liquid chromatography.