Hydrothermal hydrogenation/deoxygenation of palmitic acid to alkanes over Ni/activated carbon catalyst

To produce paraffin from hydrogenation/deoxygenation of palmitic acid,model compound of bio-oil obtained by hydrothermal liquefaction(HTL)of microalgae has been an attractive focus in recent years.In order to avoid energy-intensive separation process of water and bio-oil,it is of importance that deoxygenation upgrading of fatty acids under hydrothermal conditions similar to HTL process.Herein,it is the first time to explore the application of activated carbon(AC)-supported non-noble-metal catalysts,such as Ni,Co,and Mo,and so on,in the hydrothermal hydrogenation/deoxygenation of long-chain fatty acids,and the obtained Ni/AC-H(the Ni/AC was further H_(2)pre-reduced)is one of the best catalysts.In addition,it is found that the catalytic activity can be further improved by H_(2)pre-reduction of catalyst.Characterization results that are more low valences of nickel and oxygen vacancy can be obtained after H_(2)pre-reduction,thus significant promoting the deoxygenation especially the decarbonylation pathway of fatty acids.The total alkanes yield can reaches 95.9%at optimal conditions(280℃,360 min).This work confirmed that the low-priced AC-supported non-noble-metal catalysts have great potential compared with the noble-metal catalyst,in hydrothermal upgrading of bio-oil.

Tuning the selectivity of natural oils and fatty acids/esters deoxygenation to biofuels and fatty alcohols:A review

The chemical transformation of natural oils provides alternatives to limited fossil fuels and produces compounds with added value for the chemical industries.The selective deoxygenation of natural oils to diesel-ranged hydrocarbons,bio-jet fuels,or fatty alcohols with controllable selectivity is especially attractive in natural oil feedstock biorefineries.This review presents recent progress in catalytic deoxygenation of natural oils or related model compounds(e.g.,fatty acids)to renewable liquid fuels(green diesel and bio-jet fuels)and valuable fatty alcohols(unsaturated and saturated fatty alcohols).Besides,it discusses and compares the existing and potential strategies to control the product selectivity over heterogeneous catalysts.Most research conducted and reviewed has only addressed the production of one category;therefore,a new integrative vision exploring how to direct the process toward fuel and/or chemicals is urgently needed.Thus,work conducted to date addressing the development of new catalysts and studying the influence of the reaction parameters(e.g.,temperature,time and hydrogen pressure)is summarized and critically discussed from a green and sustainable perspective using efficiency indicators(e.g.,yields,selectivity,turnover frequencies and catalysts lifetime).Special attention has been given to the chemical transformations occurring to identify key descriptors to tune the selectivity toward target products by manipulating the reaction conditions and the structures of the catalysts.Finally,the challenges and future research goals to develop novel and holistic natural oil biorefineries are proposed.As a result,this critical review provides the readership with appropriate information to selectively control the transformation of natural oils into either biofuels and/or value-added chemicals.This new flexible vision can help pave the wave to suit the present and future market needs.

Reductive Deoxygenation of Carbonyl to Methylene by LiAlH4/InBr3

The reductive deoxygenation of aldehydes and ketones into the corresponding alkanes is accomplished by LiAlH4, in the presence of Lewis acid InBr3. It provides a convenient method to complete the transformation from carbonyl compounds to alkanes.

Mechanism of dibenzofuran hydrodeoxygenation on the Ni(1 1 1)surface

The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compound is one of the most efficient methods to upgrade coal tar.In this study,density functional theory calculations are employed to assess and analyze in detail the hydrodeoxygenation of dibenzofuran,as a model compound of coal tar,on the Ni(111)surface.The obtained results indicate that dibenzofuran can be firstly hydrogenated to tetra hy d rod i be nzofura n and hexahydfodibenzofufan.The five-membered-ring opening reaction of tetrahydrodibenzofuran is more straightforward than that of hexahydrodibenzofuran(Ea=0.71 eV vs.1.66 eV).Then,both pathways generate an intermediate 2-cyclohexylphenoxy compound.One part of 2-cyclohexylphenoxy is hydrogenated to 2-cyclohexylphenol and consecutively hydrogenated to cyclohexylcyclohexanol,and another part is directly hydrogenated to cyclohexylcyclohexanone.The hydrogenated intermediates of2-cyclohexylphenol have higher deoxygenation barriers than 2-cyclohexylphenol and cyclohexylcy clohexanol.During the hydrogenation process of cyclohexylcyclohexanone to cyclohexylcyclohexanol,the intermediate 26,formed by adding H to O atom of cyclohexylcyclohexanone,exhibits the lowest deoxygenation barrier of 1.08 eV.High hydrogen coverage may promote the hydrogenation of tetrahydrodibenzofuran,hexahydrodibenzofuran,and intermediate 26 to generate dodecahydrodibenzofuran and cyclohexylcyclohexanol.This dibenzofuran hydrodeoxygenation reaction mechanism corroborates well with previous experimental results and provides a theoretical basis for further optimization of the design of nickel-based catalysts.

Cyclopropanation Versus Deoxygenation in the Reactions of Halocarbenes with pre-Aromatic Ketones

The reactions of halocarbenes with pre-aromatic ketones 1, 2 resulted in cyclopropanation and deoxygenation products. The varying product ratio could be accounted for by a mechanism involving the carbonyl ylide intermediate.

Studies on the Aromatic Dihalocarbonyl Ylides and Their Deoxygenation

The deoxygenation reaction of heptanones, cycloheptanone, cycloheptatrienone or substituted cycloheptatrienone with dihalo-carbene results in carbon monoxide and corresponding halides. The yield of CO produced by 2 , 4 , 6-triphenylcycloheptatrienone is 2.6-3.5 times as high as that produced by the saturated heptanones. The structures, energies, charge distributions, bond orders, and other relative parameters of the dihalocarbonyl glides were calculated by using the SCF-MNDO method. The obtained data reveal that the ylides from cycloheptatrienone have aromatic structure and are different from those produced from saturated cycloheptanone. The reactivities of the dihalocarbonyl ylides are discussed. It is proposed that this aromatic structure should be responsible for the high yield of CO from the reaction of cycloheptatrienone with dihalocarbene.

Impact of Chain Length of Saturated Fatty Acids during Their Heterogeneously Catalyzed Deoxygenation

Fatty acids with different chain length were deoxygenated in the absence of hydrogen (caprylic acid (CA), lauric acid (LA) and stearic acid (SA)). The catalytic tests were carried over Pd-containing catalysts out in a batch reactor under inert gas for 6 h at 250&degC to 350&degC and pressures from 18 to 75 bar in the absence of additionally fed hydrogen. Pd-containing catalysts were tested;the best performing catalyst was 10% Pd/C with 63% undecane yield at 327&degC. These catalysts were used for a comparative decarboxylation of CA, LA and SA. At equal reaction conditions (300&degC, 6 h), the chain length of the fatty acid had a strong impact on the conversion, which was steadily increasing, whereas the alkane selectivity ran through a maximum. This work demonstrated the usability of Pd-containing catalysts for the decarboxylation of various fatty acids in the absence of additionally fed hydrogen with respect to the manufacture of hydrocarbons that can be used as blending components for fuels.

Comparison of Four Deoxygenation Techniques for Cyclodextrin Induced Room Temperature Phosphorescence

The traditional deoxygenation techniques for cyclodextrin induced room temperature phosphorescence (CD-RTP) include N-2(g)purging([1]) and Na2SO3 chemical deoxygenation. In this paper, with 1-bromocyclohexane (1-BrCH) as an external heavy atom perturber, 7,8-benzoquinoline (7,8-BQ) was used as a model compound, hydrogen and carbon dioxide are used for deoxygenation in CD-RTP and compared with two traditional deoxygenation techniques. The results show that the new deoxygenation techniques have obvious advantages such as simpler facilities, faster speed of deoxygenation and wider acidity range etc.

Factors Controlling Deoxygenation of "Floodwater" Overlying an Acid Sulfate Soil: Experimental Modeling

An incubation experiment was conducted to simulate the effect of flooding on water deoxygenation in acid sulfate soil floodplain systems. The originally oxygenated 'floodwater' could be deoxygenated immediately following 'flooding' and it is likely that this was caused mainly by decomposition of organic debris from the inundated plants. Deoxygenation eventually led to the depletion of dissolved oxygen (DO) in the 'floodwater'and it is highly possible that this resulted in the transformations of ferric Fe to ferrous Fe, sulfate to hydrogen sulfide, and organic nitrogen to ammonia (ammonification). The accumulation of these reduced substances allows the 'floodwater' to develop DO-consuming capacity (DOCC). When the 'floodwater' is mixed with the introduced oxygenated water, apart from the dilution effects, the reduced substances contained in the 'floodwater' oxidize to further consume DO carried by the introduced water. However, it appears that the DO drop in the mixed water can only last for a few hours if no additional DO-depleted 'floodwater' is added.Entry of atmospheric oxygen into the water can raise the DO level of the mixed water and lower water pH through the oxidation of the reduced substances.

Coking of Pt/γ-Al_(2)O_(3) catalyst in landfill gas deoxygen and its effects on catalytic performance

Catalytic oxidation of CH_(4) has been proved to be an attractive option for landfill gas(LFG) upgrading.However, coking of catalysts in catalytic LFG deoxygen has been clearly observed in industrial applications. In this regard, it is necessary to investigate whether coke deposition originates from CH_(4) or volatile organic compounds present in LFG, and the influence of coke deposition on catalytic performance. Herein,we evaluate the LFG deoxygen on Pt/γ-Al_(2)O_(3) catalyst in simulated LFG(CH_(4), CO_(2), O_(2), N_(2)) and its co-feed with representative volatile organic compounds, ethylbenzene, toluene, benzene and cyclohexane. The results show that the coking of the catalyst is originated from volatile organic compounds rather than CH_(4). The Pt/γ-Al_(2)O_(3) catalyst does not deactivate during LFG deoxygen process, even significant amount of coke deposited, up to 18.15%(mass). Characterization analyses reveal that although coke deposition overall covers the catalyst surface, resulting in mesopores blockage and a reduced number of accessible Pt sites, however, the coke formed, H-rich carbonaceous components, behaves as counterpart for O_(2) elimination. Besides, the coke deposited is mainly filamentous. Thus, coke formation has little negative effect on the overall catalytic performance of Pt/γ-Al_(2)O_(3) catalyst ultimately. The results obtained in this work are helpful for the rational design of robust Pt based catalysts for LFG deoxygen without undue attention to their coking properties, and also favor the innovation of more attractive purification scheme configurations.

Case Study-Performances of a Masonry House-Energy Consumption and Air-Tightness

Air-tightness and energy consumption was measured in a one-family house built in 2009 and 2010.The air-tightness fulfilled the goals,which was set to 0.3 L/s·m^(2).The energy consumption was measured from the start in May 2010.The figures in this report refer to measurements between May 2010 and October 2013 and are well below the authority demand of 55 kWh/m^(2)·year.

生物质气压烘焙技术研究进展

气压烘焙技术具备反应条件温和、能耗低、脱氧效率高、能量回收率高、半焦燃料品质近似次烟煤等优势,是一种有希望替代传统烘焙的新型技术之一。本文介绍了气压烘焙的发展脉络,综述了气压烘焙工况优化(包括原料种类、温度、压力、时间)、产物组成与理化特性,阐述了气压烘焙宏观反应路径和微观反应机理,着重介绍了半焦的燃烧、热解、气化利用途径,回顾了气压烘焙的反应器设计及其在含氯固废、污泥等处置中的拓展。最后对气压烘焙技术可将生物质转化为高品质固体燃料,直接替代煤炭进行了总结和展望。

基于高温HF/H_(2)法的YF_(3)∶Yb^(3+),Er^(3+)上转换发光性能增强研究

近年来,稀土材料因其独特的上转换光致发光特性备受关注。采用共沉淀法制备了掺杂Yb^(3+)和Er^(3+)的YF_(3)上转换发光材料。为了提高晶体结晶度和消除氧杂质的影响,采用500℃高温和HF/H_(2)气氛进行脱水除氧处理。通过X射线衍射(XRD)、氧分析仪、红外吸收光谱和荧光光谱等手段进行全面表征。结果表明:经过HF/H_(2)气氛高温脱氧处理的样品具有更高的结晶度和更优异的发光性能,表现出更高的量子产率。揭示了氧杂质对YF_(3)∶Yb^(3+),Er^(3+)上转换发光材料性能的负面影响,而采用高温HF/H_(2)气氛处理是提高发光性能的有效途径,为类似发光材料的研究提供了新思路。

高硅钢不同脱氧工艺下精炼渣系控制

针对“转炉→RH精炼→连铸”工艺流程生产的高硅钢精炼渣精准控制的难题,借助FactSage7.2商业热力学计算软件,计算了两种不同脱氧工艺下合理的精炼渣系控制范围。采用A脱氧工艺(铝脱氧硅合金化工艺)时,合理精炼渣系控制范围为氧化钙含量为53%~55%,二氧化硅含量在15%~18%,三氧化二铝含量为25%~30%,氧化镁含量为3%~5%,碱度为3~5;采用B脱氧工艺(硅脱氧铝合金化工艺)时,合理的精炼渣系的主要成分范围为:氧化钙含量为53%~56%,二氧化硅含量为12%~17%,三氧化二铝含量为25%~30%,氧化镁含量为3%~5%,碱度为3~4.5。采用工业两种对不同脱氧工艺精炼渣系吸附夹杂能力进行分析,结果表明B脱氧工艺下夹杂物数量、尺寸分布方面均优于A脱氧工艺。

全身麻醉病人术后苏醒期发生去氧饱和风险的影响因素

目的:分析全身麻醉病人在术后苏醒期发生去氧饱和风险的影响因素。方法:选取2023年1月—3月于我院接受全身麻醉手术治疗的病人268例,对病人在全身麻醉术后苏醒期可能发生的各类导致病人出现去氧饱和风险的影响因素进行单因素分析与多因素Logistics回归分析,探究全身麻醉病人在术后苏醒期发生去氧饱和风险因素。结果:268例病人中,发生去氧饱和48例,发生率为17.91%;单因素分析结果显示,美国麻醉医师协会(ASA)分级、合并呼吸系统相关疾病、合并高血压、疼痛评分、呼吸频率、咳嗽强度、术前吸入空气血氧饱和度(SpO2)<95%均为影响全身麻醉病人术后苏醒期存在的去氧饱和的影响因素(P<0.05)。多因素Logistic回归分析结果显示,ASA分级、合并呼吸系统相关疾病、合并高血压、疼痛评分、呼吸频率、咳嗽强度、术前吸入空气SpO2<95%均为病人术后苏醒期去氧饱和的独立危险因素(P<0.05)。结论:通过对全身麻醉病人术后苏醒期存在的去氧饱和风险进行分析,及时对病人可能出现去氧饱和症状的因素进行针对性的监护管理,在病人术后快速苏醒的同时,在病人苏醒安全减少去氧饱和对病人手术治疗效果的影响,帮助病人快速恢复。

沼气中氧氮气脱除方法进展

总结了从沼气或填埋气中脱除氧气和氮气的常用方法,指出了当前研究的热点方向。立足于现阶段的技术,介绍了通过物理吸附法同时脱除O2和N2的理论基础,辅以2个工业实施案例进行了详细分析。为沼气深度提纯后制成附加值更高的产品提供了一些可借鉴的方法。

铁水成分对成品氮含量影响的分析

从铁水各成分元素着手,深入探讨对成品氮含量的控制。通过对现场数据进行统计分析,得出控制成品氮含量的有效控制方向,并从脱氧、造渣等方面提出了改进措施。

研究除氧器工艺消除“小白龙”

浙江石油化工有限公司450万t/a重油催化裂化装置开工初期除氧水溶解氧一直不合格,严重影响给水管道汽包等设备的使用寿命。本文简述了目前给水除氧的主要除氧方式,分析了采样因素、除氧剂以及除氧器设备本身、操作温度、排气量、运行负荷对除氧水溶解氧的影响,并制订出对应的解决措施。通过更换除氧剂以及增加在线溶解氧分析仪,摸索除氧器最佳的工艺运行条件,解决了除氧水溶解氧不合格以及现场蒸汽“小白龙”噪音大的问题。

甘油三酯催化转化为柴油、喷气燃料和润滑油基础油

将生物质转化为可持续燃料和化学品对于解决环境问题、减少碳排放、增强能源安全以及促进经济和社会发展至关重要.在众多生物质原料中,来自不同来源的甘油三酯,如植物油、动物脂肪和微藻油,因其低氧含量和脂肪酸单元中的高度石蜡骨架,与石油衍生烃的结构相似,而特别适合生产可持续的烃燃料和化学品.这意味着通过相对简单的催化转化过程,就能有效地将甘油三酯转化为烃类产物.本文概述了甘油三酯通过加氢过程转化为无氧燃料(如柴油和喷气燃料)以及润滑油基础油等高附加值产品的过程.此外,还根据反应机理讨论了所需催化剂的重要结构性质,以及甘油三酯的不同脂肪酸组成对催化转化过程的影响.