Mechanistic insights into propylene oxidation to acrolein over gold catalysts

Direct epoxidation of propylene with H_(2)/O_(2),being the dream reaction for propylene oxide(PO)production,has raised wide scientific and industrial interests.Fundamentally understanding the formation mechanism of acrolein,as the main by-product of this epoxidation process,is very important to achieve the high yield of PO.In this study,we perform the spin-polarized density functional theory(DFT)calculations to investigate the reaction pathway from propylene to acrolein over two representative Au surfaces,that is,Au(111)and Au(100),which incorporates propylene adsorption,methyl hydrogen activation and acrolein formation.The results show that the oxygenated species(mainly O^(*),OH^(*)and OOH^(*))are able to stabilize the adsorption of propylene to decrease the energy barrier for its activation.It is demonstrated that the OOH^(*)on Au(111)surface emerges as the most easily formed oxygenated species via the H-assisted O_(2) dissociation,which is also the most active for the cleavage of methyl CAH bond in propylene.Furthermore,three pathways of acrolein formation activated by O^(*)/OH^(*)/OOH^(*)are analyzed,in which O^(*)is found as the key species to form acrolein.Finally,Bader charge analysis was conducted to explore the reasons behind the promotion effect of the oxygenated species.The insights reported here could be valuable in the design and optimization of gold catalysts for the direct epoxidation of propylene.

Critical role of mitochondrial aldehyde dehydrogenase 2 in acrolein sequestering in rat spinal cord injury

Lipid peroxidation-derived aldehydes,such as acrolein,the most reactive aldehyde,have emerged as key culprits in sustaining post-spinal cord injury(SCI)secondary pathologies leading to functional loss.Strong evidence suggests that mitochondrial aldehyde dehydrogenase-2(ALDH2),a key oxidoreductase and powerful endogenous anti-aldehyde machinery,is likely important for protecting neurons from aldehydesmediated degeneration.Using a rat model of spinal cord contusion injury and recently discovered ALDH2 activator(Alda-1),we planned to validate the aldehyde-clearing and neuroprotective role of ALDH2.Over an acute 2 day period post injury,we found that ALDH2 expression was significantly lowered post-SCI,but not so in rats given Alda-1.This lower enzymatic expression may be linked to heightened acrolein-ALDH2 adduction,which was revealed in co-immunoprecipitation experiments.We have also found that administration of Alda-1 to SCI rats significantly lowered acrolein in the spinal cord,and reduced cyst pathology.In addition,Alda-1 treatment also resulted in significant improvement of motor function and attenuated post-SCI mechanical hypersensitivity up to 28 days post-SCI.Finally,ALDH2 was found to play a critical role in in vitro protection of PC12 cells from acrolein exposure.It is expected that the outcome of this study will broaden and enhance anti-aldehyde strategies in combating post-SCI neurodegeneration and potentially bring treatment to millions of SCI victims.All animal work was approved by Purdue Animal Care and Use Committee(approval No.1111000095)on January 1,2021.

Effective VTeO/SBA-15 Catalyst Prepared by Precursor Method for the Selective Oxidation of Propane to Acrolein

Precursor decomposition was used for the preparation of VTeO/SBA-15 catalyst for the selective oxidation of propane to acrolein. The catalyst shows a better performance compared with those prepared by conventional impregnant method. A yield of 9.3% of acrolein was achieved with 2% V loadings at 500 ℃. XRD, N2-adsorption, H2-TPR, Py-IR and XPS measurements were used to unclose the relationship between the structure and performance of the catalyst.

Acrolein as a novel therapeutic target for motor and sensory deficits in spinal cord injury

In the hours to weeks following traumatic spinal cord injuries （SCI）, biochemical processes are initiated that further damage the tissue within and surrounding the initial injury site： a process termed secondary injury. Acrolein, a highly reactive unsaturated aldehyde, has been shown to play a major role in the secondary injury by contributing significantly to both motor and sensory defi- cits. In particular, efforts have been made to eluddate the mechanisms of acrolein-mediated dam- age at the cellular level and the resulting paralysis and neuropathic pain. In this review, we will highlight the recent developments in the understanding of the mechanisms of acrolein in motor and sensory dysfunction in animal models of SCI. We will also discuss the therapeutic benefits of using acrolein scavengers to attenuate acrolein-mediated neuronal damage following SCI.

Catalytic Dehydration of Glycerol under Mild Condition: An Environmentally Benign Acrolein Production

The increase of biodiesel production results in the accumulation of glycerol, which requires an increasing demand towards the study of chemical application of glycerol. Glycerol has to be transformed to other valuable chemicals, which can be used as starting materials for organic synthesis. With the final goal to find a reasonable solution for this problem we have studied the dehydration of glycerol in liquid phase using a supported HPA catalyst and developed an environmentally benign production of acrolein. Our method does not have any extreme conditions and produces a total conversion with high (93%) selectivity.

Heteropolyacid(H3PW12O40) Supported MCM-41： An Effective Solid Acid Catalyst for the Dehydration of Glycerol to Acrolein

The gas-phase dehydration of glycerol was conducted over HPW/MCM-41 catalysts,which were prepared by impregnation of different amount of H3PW（12）O（40）（HPW）on the MCM-41 support.The samples were characterized by XRD,N2 physisorption,FTIR,NH3-TPD,and pyridine-FTIR measurements.N2 physisorption results suggested that the uniform framework of MCM-41 could still be well maintained after modified with HPW.Pyridine-FTIR experiments indicate that HPW modified MCM-41 can generate rich Br？nsted acid sites.Moreover,Brnsted acid sites facilitated to improve acrolein selectivity.Under the optimized reaction conditions：40wt%HPW loading,20%glycerol concentration,and 320℃reaction temperature,the glycerol conversion and acrolein selectivity reach 85%and 80%,respectively.

THEORETICAL STUDY ON PHOTODECARBONYLATION REACTION OF ACROLEIN

Photodecarbonylation reaction of acrolein at 193nm was investigated by ab initio molecular orbital method.Our result supports photodecarbonylation mechanisms proposed by Fujimoto,and predicts that the reaction should occur in ~3ππ potential energy surface prior to the ~1ππ potential energy surface.

Kinetics and mechanism of propylene hydro-oxidation to acrolein on Au catalysts

Propylene epoxidation by H_(2)and O_(2)to propylene oxide(PO)over the Au-Ti bifunctional catalysts,as an ideal reaction for PO production,has attracted great interest.Revealing the mechanism of acrolein formation is of great importance for understanding the mechanism of molecular oxygen activation and the formation of hydroperoxo species on the Au sites.Here,we investigate the reaction mechanism of propylene oxidation to acrolein on the Au/uncalcined TS-1(Au/TS-1-B)catalyst through a combination of multiple characterization,H_(2)/D_(2)exchange,kinetics experiment,and modeling.The Ti sites are found to be non-essential to acrolein formation.Moreover,the acrolein formation on the Au/TS-1-B catalyst is confirmed to be promoted by H_(2)through hydroperoxo species formation,which includes two main steps:propylene dehydrogenation to*C_(3)H_(5)with the aid of*OOH species,and*C_(3)H_(5)oxidation by*OOH to acrolein.The latter step is determined to be the rate-determining step because the corresponding kinetics model gives the best description for experimental results.This work not only provides kinetics insights for the propylene hydro-oxidation to acrolein on the Au-Ti bifunctional catalysts,but also facilitates the rational design of Au catalysts with high activity and selectivity in the direct propylene epoxidation with H_(2)and O_(2).

铈掺杂对α-Bi_(2)Mo_(3)O_(12)纳米片催化剂丙烯选择性氧化性能的影响

采用快速微波辅助水热法制备了4种不同的Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂。在制备过程中通过调节铈的掺杂量可以改变合成催化剂的形貌和结构,成功地提高了Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂的比表面积。结果表明,煅烧温度为500℃、pH为3、掺杂量x=0.05时制备的Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂具有最高的丙烯选择性氧化性能,丙烯转化率为42.1%,丙烯醛选择性为88.3%。Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂的性能与结晶度呈负相关。用XPS表征了Bi_(2-x)Ce_(x)Mo_(3)O_(12)的氧迁移率,Bi_(2-x)Ce_(x)Mo_(3)O_(12)的催化性能与其氧流动性呈正相关。

辛弗林与橙皮苷等多酚联用抑制食品体系中丙烯醛的协同效用研究

目的 探究生物碱和黄酮单用以及多元联用对丙烯醛(acrolein, ACR)的抑制效果。方法 利用Chou-Talalay方法,采用高效液相色谱检测辛弗林(synephrine, SYN)、橙皮苷(hesperidin, HES)单用及二元联用[半抑制浓度(half maximal inhibitory concentration, IC50)恒定比例,沃柑中实际比例]对ACR的抑制活性,在此基础上与姜黄素(curcumin, CUR)、槲皮素(quercetin, QUE)、山奈酚(kaempferol, KAE)三元联用的抑制活性,采用CompuSyn软件对联用效果进行分析计算,并采用高效液相色谱-串联质谱法测定HES、SYN、CUR联用对ACR的捕获路径,分析其协同机制。最后从模型延展至食品体系,利用富含SYN和HES的柑橘和富含CUR的姜黄应用于烤鸭翅,验证多种物质叠加对ACR的抑制效果。结果 SYN与HES按照IC50恒定比例或沃柑中实际比例二元联用均具有协同抑制ACR的作用,且HES、SYN与CUR/QUE/KAE按照IC50恒定比例三元复配也对ACR的抑制具有协同增效性;相比于单用,联用时SYN、HES、CUR与ACR的加合物均有所提升,阐明协同机制为互相促进捕获更多的ACR形成加合物,从而协同抑制ACR。在烤鸭翅体系中,同时添加54.21 g/kg沃柑果肉和3.334g/kg姜黄对ACR的抑制率为57.22%。结论 SYN与HES、CUR等多酚联用对ACR的捕获具有协同增效性,协同机制为互相促进捕获更多的ACR形成加合物,且富含SYN和HES的沃柑和富含CUR的姜黄对烤鸭翅体系中生成的ACR能够达到较好的抑制效果。

Acrolein Induces Systemic Coagulopathy via Autophagy-dependent Secretion of von Willebrand Factor in Mice after Traumatic Brain Injury

Traumatic brain injury(TBI)-induced coagulopathy has increasingly been recognized as a significant risk factor for poor outcomes,but the pathogenesis remains poorly understood.In this study,we aimed to investigate the causal role of acrolein,a typical lipid peroxidation product,in TBI-induced coagulopathy,and further explore the underlying molecular mechanisms.We found that the level of plasma acrolein in TBI patients suffering from coagulopathy was higher than that in those without coagulopathy.Using a controlled cortical impact mouse model,we demonstrated that the acrolein scavenger phenelzine prevented TBI-induced coagulopathy and recombinant ADAMTS-13 prevented acrolein-induced coagulopathy by cleaving von Willebrand factor(VWF).Our results showed that acrolein may contribute to an early hypercoagulable state after TBI by regulating VWF secretion.mRNA sequencing(mRNA-seq)and transcriptome analysis indicated that acrolein over-activated autophagy,and subsequent experiments revealed that acrolein activated autophagy partly by regulating the Akt/mTOR pathway.In addition,we demonstrated that acrolein was produced in the perilesional cortex,affected endothelial cell integrity,and disrupted the blood-brain barrier.In conclusion,in this study we uncovered a novel pro-coagulant effect of acrolein that may contribute to TBI-induced coagulopathy and vascular leakage,providing an alternative therapeutic target.

Acrolein Aggravates Secondary Brain Injury After Intracerebral Hemorrhage Through Drp1-Mediated Mitochondrial Oxidative Damage in Mice

Clinical advances in the treatment of intracranial hemorrhage(ICH)are restricted by the incomplete understanding of the molecular mechanisms contributing to secondary brain injury.Acrolein is a highly active unsaturated aldehyde which has been implicated in many nervous system diseases.Our results indicated a significant increase in the level of acrolein after ICH in mouse brain.In primary neurons,acrolein induced an increase in mitochondrial fragmentation,loss of mitochondrial membrane potential,generation of reactive oxidative species,and release of mitochondrial cytochrome c.Mechanistically,acrolein facilitated the translocation of dynaminrelated protein 1(Drpl)from the cytoplasm onto the mitochondrial membrane and led to excessive mitochondrial fission.Further studies found that treatment with hydralazine(an acrolein scavenger)significantly reversed Drpl translocation and the morphological damage of mitochondria after ICH.In parallel,the neural apoptosis,brain edema,and neurological functional deficits induced by ICH were also remarkably alleviated.In conclusion,our results identify acrolein as an important contributor to the secondary brain injury following ICH.Meanwhile,we uncovered a novel mechanism by which Drpl-mediated mitochondrial oxidative damage is involved in acroleininduced brain injury.

顶空-气相色谱法与吹扫捕集-气相色谱法测定水中乙醛、丙烯醛、丙烯腈和吡啶的研究

建立了顶空-气相色谱法和吹扫捕集-气相色谱法测定水中乙醛、丙烯醛、丙烯腈、吡啶的方法。通过色谱条件、顶空条件和吹扫条件的参数优化,采用氢火焰离子化检测器,外标法定量。结果表明,顶空-气相色谱法和吹扫捕集-气相色谱法均能完全分离乙醛、丙烯醛、丙烯腈、吡啶,两种方法都有良好的线性关系,相关系数均大于0.999。顶空-气相色谱法的检出限为0.01~0.03mg/L,回收率为82.0%~113%,精密度为2.8%~7.1%。吹扫捕集-气相色谱法的检出限为0.002~0.008mg/L,回收率为87.8%~106%,精密度为2.3%~6.6%。在实际样品检测过程中,可根据实验室的配置及样品的实际特性来选择合适的分析方法。

饮料酒中丙烯醛前处理与检测方法研究进展

丙烯醛是一种高活性不饱和醛,其广泛存在于饮料酒中。丙烯醛容易和DNA、巯基化合物、蛋白质等细胞内活性物质发生反应,表现出细胞毒性、生殖毒性和遗传毒性,且已表明与多种疾病相关。本文综述了本世纪以来饮料酒中丙烯醛的研究现状,分别对样品前处理技术以及分析检测方法进行了详细介绍,并展望了饮料酒丙烯醛的研究趋势。

Performance of Mo-V-Te-P catalysts supported on the SiC for propane selective oxidation to acrolein

A series of MoTe_（0.15）V_（0.1）P_xO_n catalysts supported on the SiC were prepared by incipient wetness impregnation.The addition of P to MoTe_（0.15）V_（0.1）O_n/SiC catalysts improved the catalytic performance of selective oxidation from propane to acrolein（ACR）,and the catalyst showed highest selectivity（33.7%） and yield（10.7%） when x = 0.05.The MoTe_（0.15）V_（0.1）P_xO_n/SiC catalysts have been characterized by XRD,H_2-TPR,Raman,XPS and NH_3-TPD.The results indicated that a little H_3PMo_（12）O_（40） heteropoly acid and（VO）_2P_2O_7 formed and MoO_3 phase lessened after addition of P.The addition of P promoted the active species dispersed,increased the acidity on the surface,as well as might make the redox process easier.These significant differences improved the activity and selectivity of ACR.

Acrolein scavenger dimercaprol offers neuroprotection in an animal model of Parkinson’s disease:implication of acrolein and TRPA1

Background:The mechanisms underlying lesions of dopaminergic(DA)neurons,an essential pathology of Parkinson’s disease(PD),are largely unknown,although oxidative stress is recognized as a key factor.We have previously shown that the pro-oxidative aldehyde acrolein is a critical factor in PD pathology,and that acrolein scavenger hydralazine can reduce the elevated acrolein,mitigate DA neuron death,and alleviate motor deficits in a 6-hydroxydopamine(6-OHDA)rat model.As such,we hypothesize that a structurally distinct acrolein scavenger,dimercaprol(DP),can also offer neuroprotection and behavioral benefits.Methods:DP was used to lower the elevated levels of acrolein in the basal ganglia of 6-OHDA rats.The acrolein levels and related pathologies were measured by immunohistochemistry.Locomotor and behavioral effects of 6-OHDA injections and DP treatment were examined using the open field test and rotarod test.Pain was assessed using mechanical allodynia,cold hypersensitivity,and plantar tests.Finally,the effects of DP were assessed in vitro on SK-N-SH dopaminergic cells exposed to acrolein.Results:DP reduced acrolein and reversed the upregulation of pain-sensing transient receptor potential ankyrin 1(TRPA1)channels in the substantia nigra,striatum,and cortex.DP also mitigated both motor and sensory deficits typical of PD.In addition,DP lowered acrolein and protected DA-like cells in vitro.Acrolein’s ability to upregulate TRPA1 was also verified in vitro using cell lines.Conclusions:These results further elucidated the acrolein-mediated pathogenesis and reinforced the critical role of acrolein in PD while providing strong arguments for anti-acrolein treatments as a novel and feasible strategy to combat neurodegeneration in PD.Considering the extensive involvement of acrolein in various nervous system illnesses and beyond,anti-acrolein strategies may have wide applications and broad impacts on human health.

The First Catalytic Asymmetric Morita-Baylis-Hillman Reaction of Acrolein with Aromatic Aldehydes

We report the first example of catalytic asymmetric Morita-Baylis-Hillman reaction of acrolein with aromatic aldehydes. The use of 10 mol% of Hatakeyama＇s catalyst β-isocupreidine C4, in combination with 20 mol% of 2,6-dimethoxybenzoic acid, could catalyze the reaction to give the desired products in up to 81% ee.

吹扫捕集-气相色谱法测定水中乙醛、丙烯醛和丙烯腈的研究

建立了吹扫捕集-气相色谱法测定水中乙醛、丙烯醛和丙烯腈的分析方法,并对吹扫时间、温度、流速以及解析时间进行了优化。在优化条件下绘制工作曲线,对方法检出限、正确度和精密度进行实验。结果表明,乙醛、丙烯醛和丙烯腈的工作曲线线性相关系数均≥0.9998,检出限均为0.003 mg/L、测定下限均为0.012 mg/L,加标回收率分别为88.6%~119%、98.2%~118%、94.2%~119%,相对标准偏差分别为1.8%~9.6%、1.7%~5.3%、1.4%~4.7%。该方法前处理简单、分离效果好、检出限低、灵敏度高、正确度高、精密度好、目标组分线性相关性好,且不需要使用有机溶剂,对环境的污染和实验人员的伤害小,能满足《地表水环境质量标准》(GB 3838-2002)[1]和《生活饮用水卫生标准》(GB 5749-2022)[2]中的相关要求,可以用于地表水、生活饮用水中乙醛、丙烯醛和丙烯腈的测定。

CoTiO_(3)/g-C_(3)N_(4)复合材料的醇敏醛敏双功能特性研究

在临床医学诊断领域,基于半导体敏感的呼出气体检测具有灵敏度高、无创伤、可重复且快速等优势,其技术关键是半导体敏感材料对病程发展直接相关的典型标记物高度敏感.选用三聚氰胺、六水合硝酸钴为前驱体,利用溶胶-凝胶法以及热聚合法制得不同g-C_(3)N_(4)含量的CoTiO_(3)/g-C_(3)N_(4)气敏复合材料,采用XRD、SEM、XPS等对所得气体敏感材料进行表征和分析.结果表明,CoTiO_(3)/g-C_(3)N_(4)复合材料中,g-C_(3)N_(4)质量百分比为12%时,材料呈多孔球形结构,在不同工作温度下分别对乙醇和丙烯醛敏感,并可实现温控敏感性的转换.材料对50 ppm乙醇和丙烯醛的响应值分别可以达到32和23,展示了CoTiO_(3)/g-C_(3)N_(4)复合材料在临床呼出气检测当中潜在的应用前景.