The demand for oil and natural gas energy is increasing dramatically, and the extraction of conventional oil and gas reservoirs is in a stage of exhaustion. In order to stabilize the functionalized properties of oil-based drilling fluids (OBDF) during the extraction of oil and gas reservoirs in ultra-deep wells, the present experiments were carried out on the material (EG-NIT/CB[7]) obtained by encapsulating nitrate (NIT) in expanded graphite (EG) with porous structure through the supramolecular self-assembly property of cucurbit[7]uril (CB[7]). The structural properties were analyzed using various analytical tools and the results showed that our material synthesis was successful. And the effect of mass fraction of EG, CB[7] on the heat transfer and storage of EG-NIT and EG-NIT/CB[7] materials was investigated. The increase in mass fraction of EG can increase the thermal conductivity of EG-NIT up to 7.4 times and the introduction of CB[7] further improves the thermal conductivity of EG-NIT/CB[7] by up to 1.38 W/m·k. The latent heat value of EG-NIT/CB[7] decreased by only 4.7% after 200 cycles. Meanwhile, under the condition of 150 °C, adding EG-NIT/CB[7] to drilling fluids can reduce the temperature of drilling fluids by 2.8 °C. And it improves the stability of drilling fluids, the viscosity almost does not change, and it can also play a certain role in inhibiting the leakage of drilling fluids. Therefore, the EG-NIT/CB[7] developed by us can be practically applied in ultra-deep drilling projects.
A detailed study has been carried out on monohydroxycucurbit[7]uril-based stir-bar sorptive extraction (SBSE). A polydimethylsiloxane coating was produced by a sol–gel technique and doped with monohydroxycucurbit[7]uril ((HO) 1 Q [7]) as a selective sorbent phase. (HO) 1 Q [7] was chemically bound to the sol–gel silica substrate through hydrolysis and polycondensation. The coating possesses a porous surface, shows strong solvent resistance and good thermal stability, and has a long lifespan. Four groups of compounds, with polarities ranging from apolar polycyclic aromatic hydrocarbons to polar ketones, aromatic amines and phenols, were selected as test analytes. They were extracted with the coated stir bar, then desorbed with methanol and quantified by high-performance liquid chromatography with ultraviolet detection. The limits of detection range between 1.3 and 15 μg L −1 , the linear ranges extend from 5 to 10,000 μg L −1 , and the relative recoveries from spiked samples range between 76.4 and 97.9%. The intraday relative standard deviations range from 2.3 to 8.6% (for n = 3, at 500 μg L −1 ). Compared with a commercial PDMS-coated stir bar and a polyether sulfone-coated stir bar, the new stir bar shows wider applicability and better extraction efficiency for each group of compounds. In addition, the stir bar can simultaneously extract mixtures of chemicals of different polarities. This endows it with the potential for recovering a broad group of polar organic compounds.
A stir bar for sorptive extraction based on monohydroxycucurbit[7]uril has been prepared by a sol–gel technique. The stir bar coupled with HPLC with UV detection allows for the determination of a variety of polar compounds and multicomponent mixtures, respectively.
Xiao Tian,Li Xia Chen,Yu Qing Yao,Kai Chen,Min-Dong Chen,Xi Zeng,Zhu Tao
Upon mixing of aqueous solutions of the freely soluble building blocks cucurbit[7]uril (Q[7]) and 4-sulfocalix[4]arene (SC[4]A), white microcrystals instantly separate in near-quantitative yield. The driving force for this assembly is suggested to be the outer-surface interaction of the Q[n]. Dynamic light scattering, scanning electron microscopy, and NMR (diffusion-ordered NMR spectroscopy) analyses have confirmed the supramolecular aggregation of Q[7] and SC[4]A. Titration 1H NMR spectroscopy and isothermal titration calorimetry have shown that the interaction ratio of Q[7] and SC[4]A is close to 3:1. Moreover, the Q[7]/SC[4]A-based supramolecular assembly can accommodate molecules of some volatile compounds or luminescent dyes. Thus, this work offers a simple and highly efficient means of preparing adsorbent or solid fluorescent materials.
危险品化学品经营许可证（带存储）