查找使用阿拉丁产品的科研文献

Speed of sound measurement in ethyl tert-butyl ether and tert-amyl methyl ether by Brillouin light scattering

Xiong Zheng,Ying Zhang,Maogang He

Ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) have been considered as the potential fuel additives as the replacement of methyl tert-butyl ether (MTBE). Now it is necessary to supplement and perfect the thermophysical properties of oxygenates, including acoustic property. In this paper, speed of sound in ETBE and TAME were measured by Brillouin light scattering from 293.15 K to 680 K and from saturated vapor pressure to 10 MPa, including saturated liquid/vapor, compressed liquid and supercritical region. It is estimated that u ( T ) = 0.01 K under saturated condition; u ( T ) = 0.02 K, u ( p ) = 0.015 MPa for p  < 5.5 MPa, u ( p ) = 0.03 MPa for p  > 5.5 MPa under compressed liquid and supercritical conditions; and the relative expended uncertainty in the speed of sound is estimated to be less than 0.5% with coverage factor of k to be 2. Moreover, the reference relations of the speed of sound for saturated liquid, vapor and compressed state are presented for interpolation with the average absolute deviation of 0.23%, 0.07% and 0.33% for ETBE and 0.34%, 0.24% and 0.29% for TAME, respectively.

Catalyst-free Synthesis of 2-(tert-Butyldisulfanyl) Heterocycles from tert-Butanesulfinamide and Mercapto-substituted Imidazoles, Tetrazole, Pyrimidine and Pyridine

Yue Zhou,Xingzhao Tu,Zhijie Li,Lihong Zhou,Qingle Zeng

NaOH-Treated Hβ Zeolite: A Highly 4-Tert-butyl-phenol Selective Catalyst for Alkylation of Phenol with Tert-Butanol

Liu Kande,Wang Sitan,Zheng Lishan,Lou Shifeng,Meng Xuan,Cao Fahai,Liu Naiwang,Shi Li

The catalytic performance of Hβ zeolite treated with different concentration of NaOH on the alkylation of tert-butanol with phenol was studied. The effect of NaOH concentration on the crystallinity, morphology, textural property and acidity of Hβ zeolite was studied by X-ray diffraction (XRD), scanning electron microscope characterization (SEM), N 2 adsorption–desorption, Fourier transform infrared spectroscopy (FT-IR) and pyridine adsorption infrared spectra (Py-IR) techniques. A certain concentration of NaOH treatment can regulate the pore structure of Hβ zeolite and remove part of framework aluminum and framework silicon, thus achieving the purpose of regulating the pore structure and acidity of the catalyst. Though lower Bronsted to Lewis acid amount ratio when treated NaOH concentrations were 0.15 mol/L, leading to the increasing of selectivity to 4-TBP. The Hβ-0.2 M showed the high selectivity of 90.21% for synthesis of 4-tert-butyl-phenol (4-TBP), compared with the unmodified parent zeolite, the selectivity of 4-TBP improved 16.7%. Graphical Abstract

Isobaric Vapor–Liquid Equilibrium for Binary and Ternary Systems of tert-Butanol + tert-Butyl Acetate + Chlorobenzene at 101.33 kPa

Kai Fan,Feng Zhou,Changxu Chen,Ye Li,Weisong Li,Bo Xiao,Chunjian Xu

Isobaric vapor–liquid equilibria of tert-butanol + chlorobenzene and tert-butyl acetate + chlorobenzene binary systems and the tert-butanol + tert-butyl acetate + chlorobenzene ternary system at 101.33 kPa were measured using a circulation VLE still. The data of binary systems passed the thermodynamic consistency test of the Herington method and the Van Ness point test, and the experimental data of the ternary system also passed the Wisniak consistency test. These binary systems’ VLE data were fitted by the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models with minor deviations. Furthermore, the obtained binary interaction parameters from the binary systems were used to predict the VLE behavior of the tert-butanol + tert-butyl acetate + chlorobenzene ternary system. The rmsd of vapor and the temperature between the experimental and predicted values for the ternary system were smaller than 0.0304 and 0.81K, respectively. The results indicated that the relative volatility between tert-butanol and tert-butyl acetate obviously increased when adding chlorobenzene as a solvent. Thus, chlorobenzene is a promising solvent for the separation of the tert-butanol and tert-butyl acetate mixture system by extractive distillation.

Process and safety study of tert-butyl hydroperoxide

Dongjin Yu,Yuantong Hao,Chunsheng Cheng,Xu Ming,Jie Hu,Xiaohua Ma

Process safety for synthesis of tert -butyl hydrogen peroxide (TBHP) by tert -butyl alcohol (TBA) to react with H 2 O 2 was studied in this paper. On-line Raman spectroscopy and gas chromatography jointed analysis method was researched to monitor and analyze the changes of each components during the process to study reaction mechanism. The reaction kinetics was reproduced by apparent thermodynamics study and simulation for whole process, and the kinetics model of TBHP synthesis was obtained and with the first reported. The process safety parameter of the maximum temperature of the synthesis reaction(MTSR) and yield were predicted by response surface methodology (RSM) method and go through experimental verification further. It was found that the sulfuric acid and the concentration of TBA had great influences to reaction selectivity and yield. According to our research results, we supposed that the mechanism of TBHP synthesis would be followed by SN 1 +SN 2 . Focus on process safety, process risk assessment was done and pipe reaction to optimize TBHP synthesis was developed to change the batch process to pipe continuously. The yield of TBHP was 91.1%, conversion of TBA was 93.1%, and the selectivity of TBHP was 97.8%. The process safety parameters of heat accumulation and MTSR decreased 40.5% and 37.7% respectively comparison of the pipe continuous reaction and batch process. This study will provide guidance for intrinsic safety improvement of peroxidation reactions.

A straightforward green synthesis of N-(tert-butylsulfinyl)imines

Xirui Lv,Yue Zhou,Anguo Zhang,Lihong Zhou,Qingle Zeng

A straightforward and environment-friendly protocol for the synthesis of valuable chiral N-(tert-butylsulfinyl)imines has been developed. Different from traditional process with benzaldehydes as substrates, arylmethyl alcohols, benzylthiol, dibenzyl ether, thioether, and disulfide are used as alternative substrates to react with tert-butanesulfinamide in the presence of KOtBu under air for the synthesis of chiral N-(tert-butylsulfinyl)imines. This is a transition metal-free, mild, cost-effective, and simple process.

Distribution of 2-tert-butyl-1,4-benzoquinone and its precursor, tert-butylhydroquinone, in typical edible oils and oleaginous foods marketed in Hangzhou City, China

Ningxiang Yu,Qin Ye,Xiaohua Nie,Chaosheng Xia,Xianghe Meng

This study aimed to obtain a reliable evaluation about addition of tert -butylhydroquinone (TBHQ), and distribution of TBHQ and 2 -tert -butyl-1,4-benzoquinone (TBBQ) contents in typical edible oils and oleaginous foods marketed in Hangzhou City. Briefly, the probability of labeled with addition of TBHQ in foods decreased from 36.45 ± 2.6% to 28.78 ± 3.7% in the period from 2018 to 2020. In the 135 analyzed samples, TBHQ contents were far less than the maximum legal additive amount, and TBBQ contents ranged from below its limit of quantification (LOQ) to 13.54 ± 1.15 mg/kg. The conversion rate from TBHQ to TBBQ in edible oils was 2.94 ± 1.17%, much lower than that in other food categories. Further research determined that the process method and food composition were the main factors for different conversion rates from TBHQ to TBBQ in various food categories. In addition, oil consumption was found to be the primary source of dietary intake of TBHQ and TBBQ.

Developing an electrochemical sensor for the detection of tert-butylhydroquinone

Wei Cao,Yong Wang,Qianfen Zhuang,Luyao Wang,Yongnian Ni

In the work, a ratiometric electrochemical sensor for tert-butylhydroquinone (TBHQ) detection is constructed based on the modified electrode consisting of manganese dioxide (MnO 2 ) and electrochemically reduced graphene oxide (ERGO) nanocomposite film. MnO 2 was electrodeposited onto the electrochemically reduced graphene oxide (ERGO) placed on a glassy carbon electrode (GCE) to form the MnO 2 /ERGO/GCE. The construction process of the MnO 2 /ERGO/GCE electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The electrochemical signal responses of the TBHQ sensor were recorded by differential pulse voltammetric measurements. The experimental results demonstrate that MnO 2 can be used as the inner reference electrochemical probe, and ERGO can improve the sensitivity for TBHQ detection. It can be found that as the TBHQ concentration increases, the anodic peak current of TBHQ at the MnO 2 /ERGO/GCE increases, but the anodic peak current of MnO 2 at such the modified electrode almost remains unchangeable. The net peak current ratio between TBHQ and MnO 2 is chosen for quantitative detection of TBHQ. The developed ratiometric sensor exhibits two linear ranges of 1.0–50.0 μM and 100.0–300.0 μM for detecting TBHQ. The detection limit for TBHQ detection is estimated to be 0.8 μM on the basis of signal-to-noise ( S / N ) of 3. Moreover, the ratiometric electrochemical sensor is successfully applied for TBHQ detection in real edible oil samples.

Thermal stability evaluation of tert-butyl peroxybenzoate mixed with impurities

Yilin Zhao,Nengcheng Zhou,Min Hua,Xiuxia Guo,Wenxing Zhang,Huichun Jiang,Xuhai Pan,Juncheng Jiang

In this article, the thermal stability of tert-butyl perbenzoate (TBPB) mixed with different concentrations of toluene and p-tert-butylcatechol (TBC) was investigated. The exothermic onset temperature (T0), the heat of decomposition (ΔH), and the adiabatic temperature rise (ΔTad) of the samples were obtained by differential scanning calorimetry (DSC) and Phi-TEC II adiabatic calorimetry. The apparent activation energy (Ea) and the maximum reaction rate arrival time under adiabatic conditions were obtained by adiabatic kinetic calculations for 8 h (TD8) and 24 h (TD24). Based on Semenov’s theory, the self-accelerated decomposition temperature was calculated as a support for safe storage and transport. The results of DSC and Phi-TEC II showed that toluene was effective in reducing the thermal hazard during the decomposition of TBPB. The addition of TBC caused side reactions. The moderate addition of toluene and TBC improves the thermal stability of TBPB and can improve the safety of TBPB in industrial applications.

How to Efficiently Remove tert-butylhydroquinone from Commercial Soybean Oils to Obtain Stripped Oils: Eliminating tert-butylhydroquinone's Influence on Oxidative Stabilities of Model Oil-in-Water Emulsions

Jiaxin Chen,Xin Li,Baohua Kong,Jinglin Ma,Meiyue Liu,Chengguo Liu,Qian Liu

The present study proposes an efficient method to effectively strip tert -butylhydroquinone (TBHQ) from commercial soybean oils. Ethanol, a typically common and relatively safe organic solvent, can successfully strip TBHQ by employing a liquid-liquid extraction strategy. The results show that the volume ratio of ethanol to oil is a key factor for stripping efficiency (SE), and 4:1 (v/v) is considered the optimal parameter. When compared with traditional stripping methods via adsorbing materials (such as activated charcoal or alumina powder), the proposed ethanol extraction method can more effectively strip TBHQ from commercial oils with lower adsorption loss and higher SE. Moreover, the model O/W emulsion systems prepared using ethanol stripped oils showed the highest degree of lipid oxidation. The method can completely strip TBHQ from commercial soybean oils, thereby eliminating its influence on oxidative stabilities of model oil-in-water emulsions. Practical Applications : The ethanol stripping method can be applied as a pretreatment method to completely strip TBHQ from commercial soybean oils, and subsequently eliminate the influence of TBHQ on lipid oxidation in model O/W emulsion systems during storage.

DNA microarray-based resonance light scattering assay for multiplexed detection of DNA mutation in papillary thyroid cancer

Yaoqi Wang,Jiaxue Gao,Xianying Meng,Zhenxin Wang

Highly accurate analysis of single-nucleotide polymorphisms (SNPs) plays an important role in both disease diagnostics and personalized medicine development. In this work, a DNA microarray-based resonance light scattering (RLS) assay has been developed for multiplexed detection of papillary thyroid carcinoma (PTC) related mutation points including BRAFV600E (t1m), NRAS codon 61 (t2m), TERT promoter g.1295228 (t31m) and TERT promoter g.1295250 (t32m) with high sensitivity and selectivity by the attachment of polyvalent ssDNA modified 13 nm gold nanoparticles (ssDNAs@GNPs) followed by silver deposition for signal enhancement. The microarray-based RLS assay provides a detection limit (S/N = 3) at the sub-nanomolar level for the target ssDNAs and determines allele frequencies as low as 0.2% for t1m, 0.2% for t2m, 0.5% for t31m, and 0.5% for t32m in the cocktail of target ssDNAs, respectively. The practicability of the DNA microarray-based RLS assay is demonstrated by profiling of t2m in 50 clinical thyroid tissue samples of PTC patients, and satisfactory results are obtained.

Detecting the phase transitions of tert-butanol hydrate by terahertz spectroscopy

Yuyue Yan,Liyuan Liu,Guanhua Ren,Xueqian Zhang,Chunmei Ouyang,Hongwei Zhao,Jiaguang Han

The co-solvent system of tert -butanol and water is commonly employed in the field of freeze-drying pharmaceuticals. Investigating the phase composition and behavior of this system at low temperatures contributes to furthering its applications. In this study, THz-TDS was used to investigate the melting process of the frozen tert -butanol-water binary system for the first time. Utilizing the THz fingerprint peaks, we discovered that following the initial freezing, the system only formed metastable dihydrate tert -butanol, but near the melting point, it transformed into stable heptahydrate tert -butanol. This transition did not occur at high tert -butanol contents. Combining DFT calculations, all observed absorption peaks were attributed to the low-frequency vibration modes of each crystal. A phase diagram of the tert -butanol-water binary system was constructed based on the difference in absorbance intensity between the solid and liquid phases. The results demonstrate the potential of THz spectroscopy for applications in pharmaceutical freeze-drying.