气相色谱-质谱法测定烟用香精香料中香兰素和乙基香兰素

采用气相色谱-质谱法测定烟用香精香料中香兰素和乙基香兰素的含量。烟用香精香料样品与萃取剂的比例为1g比100mL,在500W下超声萃取10min。在气相色谱分离中用DBWAXETR毛细管柱为固定相,在质谱分析中采用选择离子监测模式。以丙酸苯乙酯为内标物。香兰素和乙基香兰素的线性范围均为0.5~200mg·L-1,检出限(3S/N)分别为0.03,0.02mg·kg-1。加标回收率在91.4%~109%之间,测定值的日内相对标准偏差(n=5)在0.43%~2.2%之间,日间相对标准偏差(n=5)在0.67%~2.6%之间。     

Ultrasound‐Assisted Wittig Reaction: A Short,Efficient Synthesis of 2‐Methoxy‐6‐Alkyl‐1,4‐Benzoquinones

A short, efficient synthesis of 2‐methoxy‐6‐alkyl‐1,4‐benzoquinones is described. Ultrasound‐assisted Wittig reaction of alkyltriphenyl phosphonium bromides with o‐vanillin in basic aqueous conditions followed by reduction with Na/n‐BuOH gave 2‐methoxy‐6‐alkylphenols. Oxidation of 2‐methoxy‐6‐alkylphenols with Fremy's salt produced the title compounds.     

Studies on the Interaction Between Vanillin and β-Amyloid Protein via Fluorescence Spectroscopy and Atomic Force Microscopy

β-Amyloid(Aβ) plaques and intracellular neurofibrillary lesions in the brain are markers of Alzheimer's disease(AD). The ability to safely decrease Aβ concentrations is potentially important as a preventive strategy for AD. The interactions between vanillin and Aβ polypeptide were investigated via fluorescence spectroscopy and atomic force microscopy(AFM). The results of fluorescence and synchronous spectroscopies illustrate that the intrinsic fluorescence of tyrosine(Tyr) residues in Aβ_1-42 aggregates can be quenched strongly upon the formation of vanillin-Aβ_1-42 complex. Thioflavine T(ThT)-induced fluorescence changes indicated that Aβ_1-42 aggregates could be disaggregated by vanillin, and the AFM images of Aβ_1-42 enunciated the depolymerization of Aβ_1-42 aggregates by vanillin in a dose-dependent manner. Vanillin may be a potential pharmacological agent for the treatment of AD.     

Optimal production of vanillin and 4-hydroxybenzaldehyde from rice straw hydrolysis residue (RSHR) over TiO2/UV and ZnO/UV system

Numerous approaches and technologies have been used in the past few decades to produce value-added chemicals from waste lignin. However, the existing technologies were not efficient and economical to produce the value-added chemicals. Rice straw hydrolysis residue (RSHR) was subjected to alkali treatment followed by photocatalysis with a 125 W UV bulb. Producing vanillin and 4-hydroxybenzaldehyde was confirmed by GCMS. The process parameters, irradiation time (IT), and catalyst dose (CD) were optimized using RSM to obtain the maximum yields of responses. Experiments were designed as per matrix generated according to central composite design (CCD) over TiO₂ and ZnO photocatalyst. The formation of compounds first increased attained their maxima, and thereafter decreased with increasing irradiation time. The higher dose of catalysts gradually increased the formation of compounds in all cases. To get maximum production of compounds, ZnO photocatalyst was found better than TiO₂ photocatalyst. The statistical analysis was also carried out in terms of RMSE, R², AAD, and % error band that showed a good agreement with the experimental results in all cases. However, the RSM model showed excellence for 4-hydroxybenzaldehyde production as compared to vanillin production over both catalysts.     

邻香草醛缩邻苯二胺与Y(Ⅲ)、Pr(Ⅲ)、Er(Ⅲ)配合物的合成与表征

首次合成了稀土硝酸盐与双希夫碱邻香草醛缩邻苯二胺（以Ｌ表示）的３种新固体配合物。通过元素分析、红外光谱、紫外光谱、差热－热重、摩尔电导及Ｘ射线粉末衍射分析等手段，确定配合物的组成为［ＬｎＬ（ＮＯ３）２］ＮＯ３（Ｌｎ＝Ｙ，Ｐｒ，Ｅｒ），并对其结构和某些物理化学性质进行了研究。     

Ni Nanoparticles Supported Montmorillonite Clay for Selective Catalytic Transfer Hydrodeoxygenation of Vanillin into 2-Methoxy-4-methylphenol

The targeted catalytic transfer hydrodeoxygenation (CTHDO) of vanillin (VAN) to 2-methoxy-4-methylphenol (MMP) holds promise as a noteworthy subject in the domain of bio-oil utilization, offering potential as a future biofuel and finding versatile use in fragrances and pharmaceutical industry. In this study, stable, cost-effective Ni nanoparticles supported on montmorillonite (MMT) clay was synthesized for eco-friendly, alcohol-mediated CTHDO of VAN to MMP. The Ni(10 %)/MMT catalyst achieved >99 % VAN conversion and 95.2 % MMP selectivity using isopropanol (IPA) as a solvent and hydrogen donor. Characterization encompassing PXRD, SEM, TEM, and XPS confirmed successful Ni integration onto MMT. NH₃-TPD, pyridine-IR, and H₂-TPR analysis evaluated catalyst surface acidity and reducibility. The synergy between surface-modulated acidity of MMT and Ni nanoparticles collectively facilitated IPA and VAN activation, driving CTHDO performance. The Ni(10 %)/MMT catalyst displayed sustained activity over five recycles. Its exceptional stability and performance underscore its potential as an eco-friendly, sustainable, non-noble transition metal-based catalyst for the hydrogenating lignin bio-oil model compounds, contributing to greener catalytic advancements.