催化碱解蓖麻油制备癸二酸的研究

以蓖麻油为原料 ,在催化剂作用下碱解裂化制备癸二酸 ,同时得到副产品仲辛醇及甘油 ,探讨了催化剂及稀释剂等对癸二酸产率的影响 ,首次采用SnO2 -V2 O5作为催化剂、液体石蜡为稀释剂 ,消除以前用的催化剂Pb3O4 及稀释剂甲酚有毒的缺陷 。

蓖麻油催化裂解制备癸二酸的清洁工艺研究

传统的蓖麻油裂解制备癸二酸工艺因使用稀释剂邻甲酚和催化剂铅氧化物而导致严重的环境污染。以对环境温和的液体石蜡作稀释剂,筛选环境友好型催化剂制备癸二酸,开发清洁生产工艺,研究发现,采用氧化铁作催化剂可取得良好的裂解反应效果。最佳工艺条件为:催化剂用量为蓖麻油质量的1.00%,V(稀释剂)∶V(蓖麻油)=4∶1,V(碱液)∶V(蓖麻油)=1∶1,反应温度280℃,反应时间4 h。在此条件下,癸二酸收率达67.2%,分离后纯度达到99.0%。表明氧化铁作为催化剂配合液体石蜡作稀释剂可望开发一条蓖麻油裂解制备癸二酸的清洁生产工艺。

蓖麻油裂解制备癸二酸过程中碱的回收工艺探究

传统的蓖麻油裂解制备癸二酸工艺中由于使用过量的碱和稀释剂邻甲酚而产生了大量的含盐含酚废水。本文在制备癸二酸的工艺中,选用毒性较小的液体石蜡作为稀释剂,从而避免了含酚废水的污染问题,同时主要针对裂解过程中因过量碱的使用而产生的含盐废水问题,研究了溶剂种类、用量对碱浸出性能的影响。结果表明,选择溶剂甲醇为浸取剂时,对裂解液中的碱具有高选择性;当溶剂用量为V(甲醇)∶V(裂解液)=6∶1,浸取次数2次,碱的回收率达到了83.3%。

N2O Decomposition over K-Ce Promoted Co-M-AI Mixed Oxide Catalysts Prepared from Hydrotalcite-like Precursors

A series of mixed oxide catalysts with different composition of Co-M-Al and Co-M-Ce- Al （M=Zn, Ni, Cu） were prepared by co-precipitation method from hydrotalcite-like compounds. The experimental results revealed the catalytic activity of Co-Ni-Al is slightly higher than that of Co-Zn-Al and much higher than that of Co-Cu-Al for direct decomposition of N2O. Moreover, addition of small amounts of Ce02 improved the catalytic activity signif- icantly and made the decomposition temperatures at which the N2O conversion was 50% and 90% （T50 and Tgo） both decreased 80 ℃ than those of Co-M-Al catalysts without CeO2 added. Further, potassium-load also promoted the catalytic activity, and the decomposi- tion temperatures of T50 and T90 both decreased approximately 50 ℃. It is significant for decomposing N2O from industries and reducing carbon emission from atmosphere.

磷酸二异辛酯(P204)合成工艺研究

研究了以异辛醇与三氯氧磷为原料,先进行酯化,然后在催化剂的作用下碱解,再经酸化、水洗、减压蒸馏后得到磷酸二异辛酯（P204）。探讨了投料比、酯化条件、催化剂用量、硫酸用量等对产物的影响,确定了最佳工艺条件,其收率高于或等于94%,纯度高于或等于95%。并用红外光谱对合成出的产物P204进行了表征。

Effects of alkaline additives on the formation of lactic acid in sorbitol hydrogenolysis over Ni/C catalyst

Lactic acid is produced as a major byproduct during sorbitol hydrogenolysis under alkaline conditions.We investigated the effects of two different alkaline additives,Ca（OH）2 and La（OH）3,on lactic acid formation during sorbitol hydrogenolysis over Ni/C catalyst.In the case of Ca（OH）2,the selectivity of lactic acid was 8.9%.In contrast,the inclusion of La（OH）3 resulted in a sorbitol conversion of 99% with only trace quantities of lactic acid being detected.In addition,the total selectivity towards the C2 and C4 products increased from 20.0% to 24.5% going from Ca（OH）2 to La（OH）3.These results therefore indicated that La（OH）3 could be used as an efficient alkaline additive to enhance the conversion of sorbitol.Pyruvic aldehyde,which is formed as an intermediate during sorbitol hydrogenolysis,can be converted to both 1,2-propylene glycol and lactic acid by hydrogenation and rearrangement reactions,respectively.Notably,these two reactions are competitive.When Ca（OH）2 was used as an additive for sorbitol hydrogenolysis,both the hydrogenation and rearrangement reactions occurred.In contrast,the use of La（OH）3 favored the hydrogenation reaction,with only trace quantities of lactic acid being formed.

A high performance non-noble metal electrocatalyst for the oxygen reduction reaction derived from a metal organic framework

The development of a non-precious metal electrocatalyst （NPME） with a performance superior to commercial Pt/C for the oxygen reduction reaction （ORR） is important for the commercialization of fuel cells. We report the synthesis of a NPME by heat-treating Co-based metal organic frameworks （ZIF-67） with a small average size of 44 nm. The electrocatalyst pyrolyzed at 600 ~C showed the best performance and the performance was enhanced when it was supported on BP 2000. The resulting electrocatalyst was composed of 10 nm Co nanoparticles coated by 3-12 layers of N doped graphite layers which as a whole was embedded in a carbon matrix. The ORR performance of the electrocatalyst was tested by rotating disk electrode tests in O2-saturated 0.1 mol/L KOH under ambient conditions. The electrocatalyst （1.0 mg/cm~] showed an onset potential of 1.017 V （[vs. RHE] and a half-wave potential of 0.857 V （vs. RHE], which showed it was as good as the commer- cial Pt/C （20 BgPt/cm2）. Furthermore, the electrocatalyst possessed much better stability and re- sistance to methanol crossover than Pt/C.

Controllable synthesis of a self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) lily as a bifunctional electrocatalyst for large-current-density alkaline seawater electrolysis

Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllable synthesis remains a challenge.Here,self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) with a lily shaped morphology was synthesized on iron foam(RuNi-Fe_(2)O_(3)/IF)via a facile one-step hydrothermal process,in which the intact lily shaped RuNi-Fe_(2)O_(3)/IF was obtained by adjusting the ratio of Ru/Ni.Benefitting from the Ru/Ni chemical substitution,the as-synthesized RuNi-Fe_(2)O_(3)/IF can act as free-standing dual-function electrodes that are applied to electrocatalysis for the hydrogen evolution(HER)and oxygen evolution reactions(OER)in 1.0 mol L^(-1) KOH,requiring an overpotential of 75.0 mV to drive 100 mA cm^(-2) for HER and 329.0 mV for OER.Moreover,the overall water splitting catalyzed by RuNi-Fe_(2)O_(3)/IF only demands ultralow cell voltages of 1.66 and 1.73 V to drive 100 mA cm^(-2) in 1.0 mol L^(-1) KOH and 1.0 mol L^(-1) KOH seawater electrolytes,respectively.The electrodes show remarkable long-term durability,maintaining current densities exceeding 100 mA cm^(-2) for more than 100 h and thus outperforming the two-electrode system composed of noble catalysts.This work provides an efficient,economical method to synthesize self-standing bifunctional electrodes for large-current-density alkaline seawater electrolysis,which is of significant importance for ecological protection and energy exploitation.

Hierarchical coral-like FeNi(OH)_x/Ni via mild corrosion of nickel as an integrated electrode for efficient overall water splitting

Efficient,stable,and noble‐metal‐free electrocatalysts for both the oxygen evolution reaction and the hydrogen evolution reaction are highly imperative for the realization of low‐cost commercial water‐splitting electrolyzers.Herein,a cost‐effective and ecofriendly strategy is reported to fabricate coral‐like FeNi(OH)x/Ni as a bifunctional electrocatalyst for overall water splitting in alkaline media.With the assistance of mild corrosion of Ni by Fe(NO3)3,in situ generated FeNi(OH)x nanosheets are intimately attached on metallic coral‐like Ni.Integration of these nanosheets with the electrodeposited coral‐like Ni skeleton and the supermacroporous Ni foam substrate forms a binder‐free hierarchical electrode,which is beneficial for exposing catalytic active sites,accelerating mass transport,and facilitating the release of gaseous species.In 1.0 mol L^-1 KOH solution,a symmetric electrolyzer constructed with FeNi(OH)x/Ni as both the anode and the cathode exhibits an excellent activity with an applied potential difference of 1.52 V at 10 mA cm^-2,which is superior to that of an asymmetric electrolyzer constructed with the state‐of‐the‐art RuO2‐PtC couple(applied potential difference of 1.55 V at 10 mA cm^-2).This work contributes a facile and reliable strategy for manufacturing affordable,practical,and promising water‐splitting devices.

Integration of Ru/C and base for reductive catalytic fractionation of triploid poplar

Lignin,which is the most recalcitrant component of lignocellulosic biomass,is also the most abundant renewable aromatic resource.Herein,reductive treatment of triploid poplar sawdust by the integration of catalytic Ru/C and a base,which afforded high yields of phenolic monomers from the lignin component and a solid carbohydrate pulp,is reported.The introduction of Cs_(2)CO_(3) led to the generation of C2 side‐chained phenols through the cleavage of C_(β)–O and C_(β)–C_(γ) bonds inβ–O–4 units in addition to C3 side‐chained phenols;the relationship between C2 and C3 was dependent on the base dosage.The reaction conditions,including base species,temperature,time,and H_(2) pressure,were optimized in terms of phenolic product distribution,delignification degree,and carbohydrate retention.The carbohydrate pulps generated from reductive catalytic fractionation in the presence of Cs_(2)CO_(3) were more amenable to enzymatic hydrolysis,indicating that this treatment of biomass constituted the fractionation of biomass components together with the breakdown of biomass recalcitrance.

Enhanced photocatalytic performance of polymeric C_3N_4 doped with theobromine composed of an imidazole ring and a pyrimidine ring

Molecular doping has been proven to be an effective approach to adjusting the electronic structure of polymeric carbon nitride(PCN)and thus improving its optical properties and photocatalytic activity.Herein,theobromine,a compound composed of an imidazole ring and a pyrimidine ring,was first copolymerized with urea to prepared doped PCN.Experimental investigations and theoretical calculations indicate that,a narrowing in band gap and a positive shift in valence band positon happened to the theobromine doped PCN,owing to the synergistic effect between the pyrimidine ring and the imidazole ring in the theobromine molecule.Moreover,it is shown that the doping with theobromine at a suitable mass fraction makes the obtained sample exhibit decreased photoluminescent emission,enhanced photocurrent density,and reduced charge-transport resistance.Consequently,an enhancement in the photocatalytic activity for water oxidation is found for the sample,which oxygen evolution rate is 4.43 times higher than that of the undoped PCN.This work sheds light on the choice of the molecular dopants for PCN to improve its photocatalytic performance.

Ultrasound assisted electrocatalytic oxidation of 3-chlorophenol in aqueous solution

Ultrasound assisted electrocatalytic process was used for enhancing decomposition efficiency of organic compounds. In this paper, the effect of ultrasonic frequency, ultrasonic intensity and pH value on 3-chlorophenol decomposition were studied. It was found that 3-chlorophenol in aqueous solution can be markedly decomposed by ultrasound assisted electrocatalytic process. The rate of decomposition increased with the increase of frequency, and low frequency is proper in the ultrasound assisted electrocatalytic system. The removal of 3-chlorophenol increased visibly with the increase of ultrasonic intensity until the intensity of 1.56 W/cm2. Alkaline condition is beneficial to 3-chlorophenol decomposition, the rate at pH 9.08 was higher than pH 2.48 and 6.85. The major intermediate formed during 3-chlorophenol decomposition was 2-chloro-pbenzoquinone, which was readily decomposed by ultrasound assisted electrocatalytic process.