查找使用阿拉丁产品的科研文献

Multistep cascade continuous flow synthesis of AOS based on microreactor

Yiming Xu,Ping Li,Haoran Ma,Ailing Huang,Wei Zhao,Xi Zhao

Sodium alpha-olefin sulfonate (AOS) is highly esteemed for its exceptional properties and widespread utility in diverse industrial applications. This study introduces a pioneering investigation into the sulfonation of olefins, employing an innovative microchannel continuous sulfonation setup. The primary focus lies in process intensification through a multistage continuous flow synthesis approach, exploring the fundamental laws governing the influence of various process conditions on the generation process. Key process parameters, including sulfonation temperature, molar ratio of raw materials, sulfonating agent concentration, material flow rate, residence time, hydrolysis temperature, and hydrolysis time, are systematically examined to elevate the final product's quality. By leveraging 1-tetradecene as the primary feedstock and successfully implementing the microreaction minipilot platform, we achieve continuous synthesis of olefin sulfonate. Notably, post-hydrolysis, we attain an outstanding content of active substances exceeding 90%. This research showcasing the successful application of microchemical technology. By focusing on process enhancement and exploring influential factors, our research results highlight the transformative potential of microchemical technology for process intensification. The developed multistep cascade continuous flow synthesis of AOS demonstrates promising prospects for process intensification in the production of valuable sulfonated compounds.

Morphological characteristics of the optic nerve head and impacts on longitudinal change in macular choroidal thickness during myopia progression

Guangyi Hu,Jiamin Xie,Ya Shi,Menghan Li,Luyao Ye,Qiuying Chen,Hanyi Lv,Yao Yin,Haidong Zou,Jiangnan He,Jianfeng Zhu,Ying Fan,Xun Xu

Purpose The aim of this study was to investigate the association between morphological characteristics of Bruch’s membrane opening distance (BMOD), border length (BL), border tissue angle (BTA), peripapillary atrophy (PPA) as well as axial length (AL) and incident decreased macular choroidal thickness (mChT) in young healthy myopic eyes. Methods A total of 323 participants aged 17–30 years were included in the current 2-year longitudinal study. Each participant underwent detailed ocular examinations at baseline and follow-up. Data of AL, refraction error, PPA area, BMOD, BL, BTA and mChT were measured individually. Incident decreased mChT was defined as follow-up mChT of participants decreased into the lowest quartile of baseline mChT. Results Subjects with longer AL, longer BMOD were more likely to have incident decreased mChT (odds ratio [OR], 1.56; 2.09, respectively, per 1 Z-score increment), whereas larger BTA was less likely to develop decreased mChT (odds ratio [OR], 0.51, per 1 Z-score increment). The area under the receiver operating curve (AUROC) of basic risk model for incident decreased mChT was 0.6284. After adding BMOD, BTA and AL separately to the basic risk model, the AUROC of the combination could reach 0.6967, 0.6944 and 0.7383, respectively. After combining BMOD, BTA and AL to the basic model, the AUROC of the combination showed the highest AUROC of 0.7608. Conclusions Bruch’s membrane opening distance and AL are significant risk factors for incident decreased mChT, whereas BTA played protective role in the deterioration of mChT. In addition, a combination of BMOD, BTA and AL could serve as earlier predictors of the attenuation of mChT in myopia progression.

Myopia outcome study of atropine in children: Two-year result of daily 0.01% atropine in a European population

James Loughman,Emmanuel Kobia-Acquah,Gareth Lingham,John Butler,Ekaterina Loskutova,David A. Mackey,Samantha S. Y. Lee,Daniel I. Flitcroft

Purpose The Myopia Outcome Study of Atropine in Children (MOSAIC) is an investigator-led, double-masked, randomized controlled trial investigating the efficacy and safety of 0.01% atropine eye drops for managing myopia progression in a predominantly White, European population. Methods Children aged 6–16 years with myopia were randomly allocated 2:1 to nightly 0.01% atropine or placebo eye drops in both eyes for 2 years. The primary outcome was cycloplegic spherical equivalent (SE) progression at 24 months. Secondary outcomes included axial length (AL) change, safety and acceptability. Linear mixed models with random intercepts were used for statistical analyses. Results Of 250 participants enrolled, 204 (81.6%) completed the 24-month visit (136 (81.4%) treatment, 68 (81.9%) placebo). Baseline characteristics, drop-out and adverse event rates were similar between treatment and control groups. At 24 months, SE change was not significantly different between 0.01% atropine and placebo groups (effect = 0.10 D, p = 0.07), but AL growth was lower in the 0.01% atropine group, compared to the placebo group (−0.07 mm, p = 0.007). Significant treatment effects on SE (0.14 D, p = 0.049) and AL (−0.11 mm, p = 0.002) were observed in children of White, but not non-White (SE = 0.05 D, p = 0.89; AL = 0.008 mm, p = 0.93), ethnicity at 24 months. A larger treatment effect was observed in subjects least affected by COVID-19 restrictions (SE difference = 0.37 D, p = 0.005; AL difference = −0.17 mm, p = 0.001). Conclusions Atropine 0.01% was safe, well-tolerated and effective in slowing axial elongation in this European population. Treatment efficacy varied by ethnicity and eye colour, and potentially by degree of COVID-19 public health restriction exposure during trial participation.

Superior enhancement of imbibition recovery by novel surfactant mixtures with a large hydrophobic group combined with nanosilica

Jian Zhang,Bo Huang,Chunhua Zhao,Wensheng Zhou,Yang Guang,Yizhuo Ge,Qiyao Shi,Minggui Chen

Low interfacial tension (IFT) drainage and imbibition are effective methods for improving oil recovery from reservoirs that have low levels of oil or are tight (i.e., exhibit low oil permeability). It is critical to prepare a high efficient imbibition formula. In this work, a novel 2,4,6-tris(1-phenylethyl)phenoxy polyoxyethylene ether hydroxypropyl sodium sulfonate (TPHS) surfactant was synthesized and evaluated for imbibition. Its structure was confirmed by Fourier transform infrared spectroscopy and the interfacial tension (IFT) of the crude oil/0.07% TPHS solution was 0.276 mN/m. When 0.1 wt% TPHS was mixed with 0.2 wt% alpha olefin sulfonate (AOS), the IFT was lowered to 6 × 10 −2 mN/m. The synergy between nanoparticles (NPs) and TPHS/AOS mixed surfactant was studied by IFT, contact angle on sandstone substrates, zeta potential, and spreading dynamics through microscopic methods. The results show that the surfactant likely adsorbs to the NP surface and that NP addition can help the surfactant desorb crude oil from the glass surface. With the addition of 0.05 wt% SiO 2 NPs (SNPs), the imbibition oil recovery rate increased dramatically from 0.32%/h to 0.87%/h. The spontaneous imbibition recovery increased by 4.47% for original oil in place (OOIP). Compared to flooding by TPHS/AOS surfactant solutions, the oil recovery of forced imbibition in the sand-pack increased by 12.7% OOIP, and the water breakthrough time was delayed by 0.13 pore volumes (PV) when 0.05% SNPs were added. This paper paves the way for enhanced oil recovery in low-permeability sandstone reservoirs using novel TPHS/AOS surfactants and SNPs.

Foam stabilized by SiO2/AOS adsorbed at the gas–liquid interface: influence of the degree of nanoparticle modification

Jiali Wang,Zhongbin Ye,Nanjun Lai,Yuaojie Huang,Hongwei Xu

Electrical tree inhibition characteristics of AOS grafted epoxy resin composites considering the coupling effects of high frequency and temperature

Yunxiao Zhang,Yuanzhang Zhang,Wenxin Lin,Yuhao Liu,Hao Hu

Encapsulation insulation materials for high-frequency transformers endure coupled electrothermal stresses from sustained high-frequency pulsed voltages and elevated operational temperatures, exhibiting inherent limitations in electrical treeing resistance that trigger premature insulation degradation. To address this, 4-acetoxystyrene (AOS) is chemically grafted onto E-51 bisphenol-A epoxy resin (DGEBA) via free radical grafting, forming DGEBA-g-AOS composites with varied AOS contents. The electrical tree growth characteristics under high-frequency (10 kHz) conditions at both room temperature (25°C) and high temperature (90°C) are systematically investigated through physicochemical characterization, quantum chemical calculations, and trap property analysis. The results demonstrate that at 25°C and 10 kHz, AOS effectively delays electrical tree initiation and propagation by trapping high-energy electrons and increasing trap density. Under 90°C and 10 kHz conditions, although the electrical tree growth rate shows no significant reduction, branch complexity decreases, and the damage area diminishes. This study provides critical insights for the development of advanced encapsulation insulation materials in high-frequency/high-temperature transformers.

Experimental Study on SiO2 Nanoparticles-Assisted Alpha-Olefin Sulfonate Sodium (AOS) and Hydrolyzed Polyacrylamide (HPAM) Synergistically Enhanced Oil Recovery

Jiani Hu,Meilong Fu,Yuxia Zhou,Fei Wu,Minxuan Li

The purpose of this study is to investigate the use of SiO2nanoparticles in assisting with surfactants and polymers for tertiary oil recovery, with the aim of enhancing oil recovery. The article characterizes the performance of SiO2nanoparticles, including particle size, dispersion stability, and zeta potential, evaluates the synergistic effects of nanoparticles with alpha-olefin sulfonate sodium (AOS) surfactants and hydrolyzed polyacrylamide (HPAM) on reducing interfacial tension and altering wettability, and conducts core flooding experiments in rock cores with varying permeabilities. The findings demonstrate that the particle size decreased from 191 nm to 125 nm upon the addition of SiO2nanoparticles to AOS surfactant, but increased to 389 nm upon the addition of SiO2nanoparticles to HPAM. The dispersibility experiment showed that the SiO2nanoparticle solution did not precipitate over 10 days. After adding 0.05% SiO2nanoparticles to AOS surfactant, the zeta potential was −40.2 mV, while adding 0.05% SiO2nanoparticles to 0.1% HPAM resulted in a decrease in the zeta potential to −25.03. The addition of SiO2nanoparticles to AOS surfactant further reduced the IFT value to 0.19 mN/m, altering the rock wettability from oil-wet to strongly water-wet, with the contact angle decreasing from 110° to 18°. In low-permeability rock core oil displacement experiments, the use of AOS surfactants and HPAM for enhanced oil recovery increased the recovery rate by 24.5% over water flooding. The recovery rate increased by 21.6% over water flooding in low-permeability rock core experiments after SiO2nanoparticles were added and surfactants and polymers were utilized for oil displacement. This is because the nanoparticles blocked small pore throats, resulting in increased resistance and hindered free fluid flow. The main causes of this plugging are mutual interference and mechanical entrapment, which cause the pressure differential to rise quickly. In high-permeability rock core oil displacement experiments, the use of AOS surfactants and HPAM for oil recovery increased the recovery rate by 34.6% over water flooding. Additionally, the recovery rate increased by 39.4% over water flooding with the addition of SiO2nanoparticles and the use of AOS surfactants and HPAM for oil displacement. Because SiO2nanoparticles create wedge-shaped structures inside highly permeable rock cores, they create structural separation pressure, which drives crude oil forward and aids in diffusion. This results in a comparatively small increase in pressure differential. Simultaneously, the nanoparticles change the rock surfaces’ wettability, which lowers the amount of crude oil that adsorbs and improves oil recovery.Keywords:SiO2nanoparticles;enhanced oil recovery;performance characterization;oil displacement experiment

Hyperbranched Copolymer as a Viscosity Reducer for Offshore Heavy Oil: From Optimization to Application

Mao Chen,Leiting Shi,Zhongbin Ye,Shanshan Zhu,Xiao Wang,Xuwei Liang,Zheng Shu,Hong Chen

This paper discussed the selection of functional monomers and optimal synthesis conditions for hyperbranched copolymer named as HVR, a novel polymer flooding chemical, intended to enhance offshore heavy oil recovery. The potential application of HVR as a polymer for oil displacement was also evaluated. Through experiments and molecular simulations, functional monomers AOS and OP-10 for Bohai heavy oil were screened out due to their high viscosity reduction rates for oil, both above 90%. Moreover, the interaction energy calculation results suggested that AOS and OP-10 were more likely to spontaneously disperse asphaltene aggregation. Furthermore, the influence of various factors on the synthesis of HVR was discussed using orthogonal design, and optimal synthesis conditions were determined. The optimal conditions for HVR synthesis are as follows: polymerization concentration of 30 wt %, initiator dosage of 1 wt %, initiation temperature of 50 °C, and system pH of 7; the sum of OP-10 and AOS accounts for 29.9 wt %, with a molar ratio of 1:1; the total amount of AM and AA accounts for 79.9 wt %, with a mole ratio of 6.5:3.5; and 3.0 G PAMAM accounts for 0.2 wt %. Moreover, HVR demonstrated good mobility control capacity and improved the recovery of heavy oil significantly in core flooding tests. Injecting a slug of 0.3 PV of HVR led to the additional recovery of 21.96 and 16.04% for oil viscosities of 350 and 500 cP, respectively. Notably, HVR’s additional recovery was over 7% higher than that of conventional hydrophobically associating polymer. These findings highlight the potential of HVR as a novel polymer to enhance the heavy oil recovery.

Optimization of Gas-Liquid Sulfonation in Cross-Shaped Microchannels for α-Olefin Sulfonate Synthesis

Yao Li,Yingxin Mu,Muxuan Qin,Wei Zhang,Wenjin Zhou

The gas-liquid sulfonation of α-olefin sulfonate (AOS) in falling film reactors faces significant limitations, primarily due to poor mass transfer efficiency and excessive byproduct formation. To overcome these challenges, a novel cross-shaped microchannel reactor was developed for the continuous gas-liquid sulfonation of α-olefin (AO) with gaseous sulfur trioxide (SO3). The influence of key process parameters, including gas-phase flow rate, reaction temperature, SO3/AO molar ratio, and SO3volume fraction, on product characteristics and their interactions was systematically investigated using the single-factor experiment and response surface methodology (RSM). A high-precision empirical model (coefficient of determination,R2= 0.9882) to predict product content was successfully constructed. To achieve multi-objective optimization considering product active substance content and energy efficiency, a strategy combining a two-population genetic algorithm with the entropy-weighted TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method was implemented. Optimal conditions were determined as follows: gas-phase flow rate of 228 mL/min, reaction temperature of 52 °C, SO3/AO molar ratio of 1.27, and SO3volume fraction of 4%. Compared to conditions optimized solely by RSM, this multi-objective approach achieved a significant 10% reduction in energy efficiency, with only a marginal 3.8% decrease in active substance content. This study demonstrates the feasibility and advantages of microreactors for the efficient and green synthesis of AOS.

Enhanced CO2 foam stabilization with fluorescent nano polymer microspheres for improved oil recovery: Insights from microscopic and macroscopic displacement studies

Hongbin Yang,Haocong Li,Hao Xu,Ruichao Wang,Yubin Zhang,Luyao Xing,Xin Chen,Liang Peng,Wanli Kang,Bauyrzhan Sarsenbekuly

CO 2 foam flooding is an effective enhanced oil recovery (EOR) technique that has been extensively studied for development of low-permeability reservoirs. However, during its application, poor foam stability often leads to severe gas channeling, resulting in lower recovery. In order to improve the foam stability, a CO 2 foam system was constructed by using fluorescent nano polymer microspheres (PARC(Flu-Ac)-5) and anionic surfactant sodium α-alkene sulfonate (AOS). The macroscopic and microscopic stability of the CO 2 foam system stabilized by PARC(Flu-Ac)-5 was investigated through its rheological properties, adsorption characteristics, and microscopic morphology. Furthermore, the sweep range of different foam systems and the stability of the foam in the channel were explored through the microscopic visualization model. Finally, the plugging and oil displacement performance of the CO 2 foam system stabilized by fluorescent nano polymer microspheres was evaluated through dynamic core flooding experiments conducted under CO 2 flooding reservoir conditions. Thus, the oil displacement mechanism of fluorescent nano polymer microspheres stabilizing CO 2 foam was revealed. The experimental results demonstrate that PARC(Flu-Ac)-5 microspheres greatly enhance the stability of CO 2 foam by adsorbing at the gas-liquid interface. It remains stable for 30 min when formed with 5 % oil content. The microspheres' distinctive elastic deformation characteristics enable their migration and subsequent plugging of the pores following foam rupture, thereby establishing a dual anti-gas channeling mechanism. The total recovery of CO 2 foam system stabilized by fluorescent nano polymer microspheres is 46.71 %. The oil displacement effect is better than that of the single AOS foam system, and the total recovery rate is increased by 12.02 %. By adsorbing at the gas-liquid interface of foam liquid film, PARC(Flu-Ac)-5, acting as a foam stabilizer, enhances both the stability and oil resistance of foam within porous media. This adsorption behavior thereby enabling the foam to maintain its integrity upon encountering crude oil and preventing foam coalescence and defoaming. Concurrently, under the Jamin effect of the foam, the foam preferentially occupies the pore space in high permeability layers, and the injected fluid is diverted toward unswept regions following the plugging of high permeability pathways. Consequently, the sweep range and the driving ability of the subsequent foam to enter the blind end are increased, and the recovery rate of crude oil is improved. This work lays a theoretical foundation for the field application of polymer microspheres stabilized CO 2 foam system.

Alginate oligosaccharide structures differentially affect DSS-induced colitis in mice by modulating gut microbiota

Shuang Lu,Kai Na,Jiani Wei,Ting Tao,Li Zhang,Ying Fang,Xiangyu Li,Xiaohua Guo

Alginate oligosaccharides (AOS) are divided by their monomer sequences into three types: oligomannuronate (MAOS), oligoguluronate (GAOS), and heterogeneous AOS (HAOS). However, how these AOS structures differentially regulate health and modulate gut microbiota is unclear. We explored the structure-function relationship of AOS both in an in vivo colitis model and an in vitro enterotoxigenic Escherichia coli (ETEC)-challenged cell model. We found that MAOS administration significantly alleviated the symptom of experimental colitis and improved the gut barrier function in vivo and in vivo . Nevertheless, HAOS and GAOS were less effective than MAOS. The abundance and diversity of gut microbiota are obviously increased by MAOS intervention, but not by HAOS or GAOS. Importantly, microbiota from MAOS-dosed mice through FMT decreased the disease index level, alleviated histopathological changes, and improved gut barrier function in the colitis model. Super FMT donors induced by MAOS but not by HAOS or GAOS, seemed to exert potential in colitis bacteriotherapy. These findings may aid in establishing precise pharmaceutical applications based on the targeted production of AOS.