JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2021
·
IF 4.291
Jiamin Pan,Jie Ma,Lian Liu,Denghui Li,Yuting Huo,Hui Liu
Based on the known deprotection reaction of thioacetal initiated by Hg 2+ , a new type of fluorescent probe 3-(4-(1,3-dithiolan-2-yl) phenyl)-9H-carbazole (DTCB) is designed and synthesized successfully. The probe shows a good fluorescence response to Hg 2+ in THF-H 2 O ( f w = 5%) mixed system. The addition of Hg 2+ greatly enhances the fluorescence intensity of the probe and changed from dark blue to green fluorescence. Within a large Hg 2+ concentration range (0–6×10 −5 mol·L −1 ), the fluorescence intensity at 480nm presents good linear with the Hg 2+ concentration (R 2 = 0.993), and the detection limit of the probe to Hg 2+ is below 2.05×10 −7 mol·L −1 . The DTCB probe shows good selectivity and anti-interference performance, and many metal ions and anions hardly effect on its detection performance. The sensing mechanism is confirmed by theory calculation based on DFT and TD-DFT theories, and the intramolecular charge transfer (ICT) is responsible for the significant fluorescence change of probe DTCB. Meanwhile, the probe is applied to the detection of Hg 2+ in real water samples; and it is interesting that the DTCB-based test strip firstly reveals the strong fluorescence from solid-state 3-(4-formylphenyl)-9H-carbazole (FCB) with Hg 2+ adding. The results show that the probe based on DTCB has potential application prospect in actual sample analysis.
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2023
·
IF 5.3
Xu Zhang,Haowen Cui,Qinfang Li,Haian Xia
It is of great significance to develop an affordable and environmentally friendly method for producing 5-hydroxymethylfurfural (HMF) and furfural from inexpensive and abundant agricultural waste. Herein, FePO4 combined with organic acids such as mandelic acid were used as catalysts in a one-pot catalytic conversion of untreated wheat straw into HMF and furfural in a two-phase system of THF/H2O saturated by NaCl. H+, Fe(OH)2+, and Fe(OH)2+ originated from partially dissolved FePO4 in hot water together with organic acids provided Brønsted and Lewis acid sites for the cascade conversion of wheat straw. Whereas organic acid could regulate the concentrations of Lewis and Brønsted acid sites to promote the dehydration process of fructose and hinder the production of by-products and humins, boosting the yield of HMF and furfural. The response surface methodology (RSM) was used to optimize the reaction conditions. The highest yield of HMF was 62.9% at 200 °C and 120 min, which is higher than the reported yield of HMF using lignocellulose as raw material in the current literature. Furfural has also achieved a higher yield (93.9%) at 180 °C and 90 min. This study demonstrates the rationality of the deployment of lignocellulose to produce furan compounds by organic acids and FePO4, providing the possibility for efficient production of HMF and furfural from recalcitrant agricultural waste.
研究领域:
化学工程
·
绿色化学
·
生物炼制
·
可持续化学
✓ 已验证
产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2017
·
IF 3.473
Mingguang Zhu,Youzhen Zhuo,Kaicong Cai,Hongyu Guo,Fafu Yang
A novel perylene liquid crystal with diphenylacrylonitrile groups on 1,7-bay positions was synthesized in high yield. This highly decorated perylene bisimide showed the ordered hexagonal columnar liquid crystalline behaviour between 124.9 and 189.5 °C. Upon excitation of 480 nm, an attenuation of fluorescent intensity was observed with the increase of water fraction in THF/H 2 O mixtures. However, the fluorescence intensity enhanced dramatically and attained a maximum value at water fraction of 40% in THF/H 2 O systems when excited at 330 nm. The fluorescence intensity increased by 10 times and the pseudo Stokes shift achieved 251 nm. These phenomena were well elucidated by the AIE and FRET effect, which were supported by the investigation of fluorescence quantum yield and fluorescence lifetime .
研究领域:
材料科学
·
化学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Armin Rezayan,Ke Wang,Renfeng Nie,Tianliang Lu,Jianshe Wang,Yongsheng Zhang,Chunbao Charles Xu
Catalytic transformation of carbohydrates to bio-chemicals such as 5-Hydroxymethylfurfural (HMF) has become a hot research topic, but development of cost-effective/efficient catalysts and processes remains a challenge for industrial application. In this study, efficient bifunctional Sn/KIT-1/C catalysts with controllable acid sites were synthesized and applied for glucose-to-HMF conversion. Strong Lewis acid sites were introduced into the framework of disordered mesoporous silica by liquid-phase grafting of tin chloride, and Bronsted acid sites were generated by inserting carbon into the mesopores, followed by controlled oxidation of the carbon. Characterizations revealed that optimizing the amount of carbon source, and carbonization and oxidation temperature provided a proper amount and strength of acidity that could significantly catalyze glucose dehydration reaction to HMF with suppressed byproducts formation. The best catalyst Sn/KIT-1/C(75–400-300) demonstrated superior catalytic performance at 175 °C for 2 h under THF/H 2 O biphasic system, obtaining 78.4 ± 2.1% and 82.9 ± 2.4% HMF yield and selectivity, respectively. The high activity may be attributed to catalyst high surface area/porosity, and the presence of well-balanced amounts and strength of Lewis/Bronsted acid sites. The catalyst could maintain its excellent catalytic activity for five consecutive runs, suggesting the high physical–chemical stability of the catalyst. The results obtained in this work demonstrated that bifunctional metal-supported silica–carbon composites can be a promising catalyst for simple/complex carbohydrates conversion to HMF/bio-based chemicals.
研究领域:
催化
·
化学工程
·
材料科学
·
生物化学
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2021
·
IF 4.089
Jiajun Chen,Zhinan Fan,Chi Zhang,Huatian Duan,Li-Juan Fan
To detect neomycin, one of the common antibiotics in the environment and in food and which may pose harm to human health, a fluorescence sensing system based on an amphiphilic conjugated polyelectrolyte (CPE) was constructed. The CPE, PFPE-COONa, with poly[fluorenyl-alt-p-phenyleneethynylene] (PFPE) as the backbone and carrying four pendant hydrophilic carboxylate groups and two long hydrophobic alkoxyl chains in each repeat unit, was successfully synthesized. The photophysical study found that PFPE-COONa emission was solvent dependent, displaying a 58 nm red shift in wavelength and a nearly 150-fold enhancement in intensity for the emission maximum, by varying the ratios of the mixed solvent. Based on an understanding of the photophysics, the sensing condition was optimization to dissolve PFPE-COONa in the THF/H2O mixed solvent with a ratio of 1:1. The sensing system displayed excellent sensing performance toward neomycin at a neutral pH value. The blue-to-green fluorescence color change of the polymer solution, which can be clearly observed by the naked eye, upon around 0.7 μM of neomycin and the limit of detection (LOD) was calculated to be 0.78 nM. In addition, other possible interferents had no significant influence on the detection of neomycin. The mechanism study confirmed that the polymer aggregation, which induced strong electrostatic static interaction between the carboxylate groups of high density in the polymer and the dense positively charged primary amino groups in neomycin, was the main reason for such a visually fluorescent color change. This study provides a general strategy for the future design of sensing systems for organic pollutants.
研究领域:
分析化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）