Joseph Dean,Natalia Buckler Reinoso,Francesco Spiedo,Carola Romero Fernández,Bhaven Patel
Flow chemistry has shown significant versatility over the last two decades, offering advantages in efficiency, scalability, and sustainability. In this study, the continuous stirred tank reactor (CSTR) was used to optimise the synthesis of α-hydroxyphosphonates via the Pudovik reaction and their subsequent conversion to phosphates through the phospha-Brook rearrangement. The study highlights that using CSTRs allows for better control over reaction parameters, leading to reduced reaction times and improved yields compared to traditional batch methods. The optimised conditions successfully facilitated a range of organophosphates, including electron-rich and electron-poor derivatives, with high efficiency. Additionally, a one-pot tandem process combining the Pudovik reaction and the phospha-Brook rearrangement was developed, reducing reaction times to two hours while maintaining comparable yields. This work demonstrates the potential of CSTRs in flow chemistry for synthesising complex organophosphorus compounds, achieving higher reaction yields and shorter reaction times, highlighting the effectiveness of continuous flow methodologies.
Siyuan Wang,Guang Wang,Xi Yang,Hang Yang,Mengjian Zhu,Sen Zhang,Gang Peng,Zheng Li
Two-dimensional (2D) layered semiconductor materials, such as transition metal dichalcogenides (TMDCs), have attracted considerable interests because of their intriguing optical and electronic properties. Controlled growth of TMDC crystals with large grain size and atomically smooth surface is indeed desirable but remains challenging due to excessive nucleation. Here, we have synthesized high-quality monolayer, bilayer MoSe2triangular crystals, and continuous thin films with controlled nucleation density via reverse-flow chemical vapor deposition (CVD). High crystallinity and good saturated absorption performance of MoSe2have been systematically investigated and carefully demonstrated. Optimized nucleation and uniform morphology could be achieved via fine-tuning reverse-flow switching time, growth time and temperature, with corresponding growth kinetics proposed. Our work opens up a new approach for controllable synthesis of monolayer TMDC crystals with high yield and reliability, which promote surface/interface engineering of 2D semiconductors towards van der Waals heterostructure device applications.Keywords:transition metal dichalcogenides (TMDCs);MoSe2;controlled growth;reverse-flow chemical vapor deposition (CVD)
Hao Zhou,Qin Liu,Xiuhong Zhong,Yaqi Chu,Zhaojiang Wang,Yanqin Wang
To achieve the valorization of whole compositions of lignocellulosic biomass, flow fractionation (FF) was developed based on the flow chemistry of the major components of biomass, i.e., glucan, xylan, and lignin. Three kinds of solvent, i.e., water, formic acid, and p -toluenesulfonic acid (p-TsOH), were employed in FF treatments of poplar wood for an evaluation of performance in structure and yield of products. The advantage of FF was firstly confirmed by the nearly complete recovery of glucan in solid product, and the greatly enhanced digestibility of enzymatic hydrolysis as indicated by the glucose yield of 68.1 % at a low cellulase dosage of 10 FPU/g solid product from water treated poplar wood. The second advantage of FF was the rapid hydrolysis and very slight degradation of xylan for the three solvents explored, especially for water as indicated by the xylose yield of 80.3 % from poplar wood treated at 200 °C just for 15 min.. Last but not least, structure-preserved lignins were harvested from biomass with good yield, e.g., 40.3 % of lignin yield and 99.8 % of β-O-4 retention from poplar wood using water as solvent. Thus-obtained lignin (F72T130t30) was successfully transformed to hydrocarbons over Ru/Nb 2 O 5 catalyst with the yield of 21 wt%. In short, these remarkable performances of FF in products structure and yield build a feasible valorization of lignocellulosic biomass for sustainable biorefinery.
危险品化学品经营许可证（带存储）