FUEL
·
2025
·
IF 7.5
Junjie Liu,Jianmin Wu,Qiwen Sun,Jiancheng Wang,Yan Sun,Hengxuan Zhang
The high-viscosity poly-alpha-olefin was prepared from Fischer-Tropsch mixed α-olefins (FTO) polymerization under [EBIZrCl 2 /Al( i Bu) 3 /[Ph 3 C] + [B(C 6 F 5 ) 4 ] - system (EBI = rac -C 2 H 4 (1-Ind) 2 ), and its mechanism was investigated by in situ UV–Vis, 1 H NMR and ESI-MS. The results show that the kinematic viscosity at 100°C (KV 100 ), viscosity index (VI) and yield of product reach to 306.3 cSt, 244 and 81.12 % under optimum reaction condition, respectively. Through adjusting temperature to 20°C, in situ UV–Vis, 1 H NMR and ESI-MS are conducted to monitor the formation of origin species (EBIZr( i Bu) 2 + ), active species (EBIZr-σ-y n + (y = nonenyl, decenyl and undecenyl, n ≥ 1)), reactivated species and dormant species (EBIZr-η 3 -(1-R-C m H m+1 ) + (R = n-propyl and m = 6 or 7 or 8)). The simultaneous generation of active and dormant species is observed, and the reaction process is described as [FTO] + [catalyst] → [active species] + [dormant species]. This reaction fitting curve also conforms to the Boltzmann (R 2 ≥ 0.993). The effect of different types of olefins on catalytic evolution and product properties is investigated. The existence of multiple α-olefins inhibits the formation of the second inactivate species found in 1-decene polymerization. However, the multiple isomeric olefins further enhance the possibility of dormant species generation, because of the promotion of β-H concentration in catalytic system, leading to the higher activation energy (19.597kJ/mol) than pure 1-decene (10.949kJ/mol). Based on those findings, a possible mechanism in ansa-zirconocene catalyzed to prepare high-viscosity poly-alpha-olefin from Fischer-Tropsch mixed α-olefins is proposed.
研究领域:
高分子化学
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催化化学
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石油化学
·
材料科学
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工业化学
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反应机理
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流变性能
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 7
·1680
·
IF 3.1
Xiao Sang,Ke Han,Manfu Zhu,Liran Ma
Controlling friction by light field is a low-cost, low-energy, non-polluting method. By applying ultraviolet light on the surface of photosensitive materials, the properties of the friction pairs or lubricant can be influenced, thus achieving the purpose of reducing friction. In this study, TiO2, an inorganic photosensitive material, was selected to investigate the modulating effect of light fields on friction lubrication when using polyalphaolefin (PAO) base oil as a lubricant, and the modulation law of light fields on the friction lubrication behavior was investigated under different loads (1–8 N), different speeds (20–380 mm/s), and different viscosities (10.1–108.6 mPa·s) of PAO base oil. The experimental results showed that light treatment could reduce the friction coefficient of PAO4 base oil lubrication from 0.034 to 0.016, with a reduction of 52.9% under conditions of 3 N-load and 56.5 mm/s-speed, and the best regulation effect could be achieved under the mixed lubrication condition. After TiO2was treated with ultraviolet light, due to its photocatalytic property, PAO molecules were oxidized and adsorbed on the TiO2surface to form an adsorption layer, which avoided the direct contact of rough peaks and thus reduced the friction coefficient. This study combines photosensitivity, photocatalysis, and friction, presenting a method to reduce the friction coefficient by applying a light field without changing the friction pairs or lubricants, which provides a new direction for friction modulation and gives new ideas for practical applications.
研究领域:
材料科学
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摩擦学
·
光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Cong Wang,Gang Li,Zheng Huang,Anfeng Peng
The cumbersome air isolation process is one of the main constraints in the development of linear α-olefins prepared by ethylene oligomerization. An effective way to solve this problem is to eliminate the use of an alkyl-aluminum cocatalyst. Herein, two forms of Versailles/Santa Barbara-5 (VSB-5) (VSB-5-H3PO4 and VSB-5-NaH2PO2) are prepared and used as heterogeneous catalysts in ethylene oligomerization in the presence of LiAlH4 as a cocatalyst. Compared to other Ni-MOFs and Ni silica–aluminate catalysts, VSB-5s maintain a wider distribution of Linear α-olefin (LAO) products at relatively high activity. In the reuse test of the catalyst, the Al species from LiAlH4 cover the surface of the catalyst and decrease its activity, which could be removed by acid treatment. In situ IR studies show that active centers for ethylene oligomerization may form in VSB-5 assisted by LiAlH4. In addition, a Cossee–Arlman-type mechanism is proposed.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ORGANOMETALLICS
·
2016
·
IF 4.186
Wenlong Luo,Antai Li,Shaofeng Liu,Hongqi Ye,Zhibo Li
A series of chromium(III) complexes, LCrCl3 (Cr1–Cr4: L = 2-(N-R2-benzimidazol-2-yl)-6-(3,5-R1-pyrazol-1-yl)pyridine; Cr1: R1 = H, R2 = H; Cr2: R1 = Me, R2 = H; Cr3: R1 = Me, R2 = Me; Cr4: R1 = Me, R2 = Bn), were synthesized and characterized by IR spectroscopy and elemental analysis. The studies of the solid state of Cr2 and Cr3 revealed distorted octahedral geometries around the chromium centers by X-ray diffractions. In the presence of MAO, Cr1–Cr4 exhibited high activities toward ethylene oligomerization (up to 2.17 × 106 g·mol–1(Cr)·h–1) and ethylene polymerization (up to 6.78 × 105 g·mol–1(Cr)·h–1). The oligomers were produced with high selectivity for α-olefins (>99%), confirmed by FT-IR and 13C NMR, and the distributions followed the Schulz–Flory equation. Various reaction parameters including the amount of cocatalyst, reaction temperature, and time were evaluated in detail, and it was evident that the title complexes had good thermal stability and the substituents on imidazole-N of the ligands dramatically impacted the catalytic activities as well as the distribution of the products.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Siwei Chen,Qingqing Chen,Baogang Wang,Hongsheng Lu
The application of carbon dots (CDs) as lubricant additives of nonpolar oils such as poly-α-olefins (PAOs) has been greatly hindered because most of CDs derived from the bottom-up method were water-soluble. In this work, the oil-soluble polymer brushes grafted CDs were synthesized by the surface-initiated atom transfer radical polymerization of bis-alkyl chain monomers. As expected, the polymer grafted CDs exhibited the excellent long-term dispersion stability in PAO owing to the principle of similar compatibility. As the lubricant additives of PAO4, the CDs showed the best friction-reducing and anti-wear properties when the polymerization time was 2 h. Adding 1 wt% of CDs could make the coefficient of friction and wear volume of PAO4 reduce by 64.1 % and 49.6 %, respectively. Moreover, both the tribological properties and anti-rust performance of CDs were superior to the commercially used ZDDP. The distinguished friction-reducing and anti-wear properties of CDs were attributed to the synergistic lubrication of carbon cores and polymer brushes. The rolling, repairing and polishing action of carbon cores, together with the tribo-reactions of polymer brushes, resulted in the formation of tough lubricating films on the rubbing surfaces, thereby tremendously alleviating the friction and wear of tribopair. The impressive anti-rust performance of CDs could be assigned to their strong adsorption ability on metallic surfaces. The above results are hopeful to provide useful information for the design and development of efficient multifunctional additives such as polymer-grafted metallic or inorganic nanomaterials.
研究领域:
材料科学
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润滑工程
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2024
·Vol. 14
·期 1
·70
·
IF 3.8
Min Zhang,Hongwei Xiang,Xiaodong Wen
This investigation explores the synthesis of advanced catalysts for epoxidizing long-chain linear α-olefins, a pivotal process in the chemical industry for generating critical intermediates. Employing a hydrothermal technique, we developed four distinct catalysts (CS-1–4), methodically modulating the Ca/Sn ratio to elucidate its impact on the catalysts’ physicochemical properties. Our research uncovered that an escalated Ca/Sn ratio induces a morphological shift from octagonal to cubic structures, concomitant with a diminution in particle size and an enhancement in specific surface area. Significantly, the CS-3 catalyst outperformed others in 1-octene epoxidation, an efficacy attributed to its augmented surface alkalinity and proliferation of medium-strength alkaline sites, likely emanating from increased surface oxygen defects. Subsequent hydrogen reduction of CS-3 further amplified these oxygen defects, yielding a 10% uptick in catalytic activity. This correlation underscores the potential of oxygen defect manipulation in optimizing catalytic efficiency. Our findings contribute a novel perspective to the development of robust, high-performance catalysts for α-olefin epoxidation, seamlessly aligning with the principles of sustainable chemistry.Keywords:long-chain linear alpha-olefin;perovskite oxide;CaSnO3;oxygen vacancy;epoxidation
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Meng Chen,Wei Lu,Hejun Zhu,Leifeng Gong,Ziang Zhao,Yunjie Ding
Linear α-olefins (C8–C12 α-olefin, LAOs) are acknowledged as high-value-added chemicals in both lubricant production and the polyolefin industry. An alternative route to the synthesis of high-purity LAOs is the dehydration of linear long-chain n-alcohols, whereas elevating the activity and selectivity of catalysts remains a challenge. Herein, we presented that on using sodium-modified γ-Al2O3 as the catalyst, a high selectivity (up to 96.87%) to 1-decene was achieved, and an optimized experimental condition (329 °C and 0.25 h–1) was found using the response surface method. Characterization results including X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), pyrolysis (Py)-IR, NH3-temperature-programmed desorption (TPD), and CO2-TPD showed that a suitable ratio (∼0.4 wt %) of sodium impregnation could inhibit the strong acid sites of the catalyst, and sodium impregnation led to the formation of additional base sites, which accounted for the synergistic effect with other acid sites to promote further conversion of ethers to olefins. This work is of significance for the synthesis of LAOs from long-chain n-alcohols.
研究领域:
催化化学
·
材料科学
·
石油化工
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 27
·11968-11976
·
IF 3.591
Xingyu Yang,Xu Li,Jinxiang Dong
The epoxidation of linear-chain α-olefins over heterogeneous catalysts is still challenging, while epoxides as versatile raw intermediates are highly desirable. Here, we describe the facile preparation of farringtonite, obtained via the calcination of commercial anhydrous trimagnesium phosphate, and its novel application in the epoxidation of olefins. Farringtonite was characterized via XRD, FT-IR, SEM-EDS, and CO2-TPD studies. The CO2-TPD data exhibited that farringtonite mainly possesses medium-base sites. The catalytic activity of farringtonite was optimized via adjusting different parameters, including the solvent, temperature, amount of H2O2, farringtonite loading, stirring rate, and so on, using 1-octene epoxidation as the model reaction and 30% H2O2 as the oxidant. The results from 1-octene epoxidation indicated that the farringtonite catalyst exhibited efficient catalytic activity, with high conversion of up to 85.2% and epoxide selectivity of 87.6% under the optimal conditions. In addition to 1-octene, 1-decene and 1-heptene were also used, achieving good-to-excellent conversions with high selectivities. In addition, farringtonite could be recycled four times with the preservation of its high catalytic activity. From a mechanistic standpoint, the in situ generation and consumption of Payne's reagent is responsible for the epoxidation reaction. Therefore, farringtonite serves as an excellent catalyst for the epoxidation of α-olefins.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Ruida Zhao,Puke Mi,Sheng Xu,Suqin Dong
In this paper, poly-α-olefins (PAO) containing quaternary carbon centers were prepared by two-step oligomerization using a metallocene catalyst followed by a Ziegler–Natta catalyst. First, the 1-decene dimer was oligomerized with [t-BuN(Me)2C(η5-C5H4)]ZrCl2, and the effects of the oligomerization temperature, Al/Zr molar ratio, and catalyst loading on the oligomerization were investigated. In the second step, the obtained 1-decene dimers were copolymerized with 1-decene with TiCl4/Et2AlCl, and the effects of the catalysts, monomer/dimer ratio, and α-olefin species on the copolymerization were investigated. The composition and structure of the dimers and copolymerization products were characterized by gas chromatography (GC) and 1H NMR and 13C NMR spectroscopy. The results of GC and 13C NMR analyses indicated that the metallocene catalyzed the formation of the 1-decene oligomerization product, resulting in the branched olefin dimer being the major product, and the existence of quaternary carbons in the 1-decene/1-decene dimer copolymerization product could also be found. The polymerization mechanism for the formation of the quaternary carbon centers is proposed. The 1-decene/1-decene dimer copolymerization product containing quaternary carbon centers has a kinematic viscosity of 10.8 mm2/s at 100 °C, a viscosity index of 165, and a pour point of −52 °C; thus, the product with quaternary carbon centers has a better viscosity–temperature performance and low-temperature fluidity than those of the 1-decene oligomerization product and typical PAO products, but the kinematic viscosity is similar.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
WEAR
·
2023
·
IF 5
Hua Jiang,Xianjun Hou,Qifan Yu,Mohamed Kamal Ahmed Ali
This study comprehensively investigated physicochemical and tribological performance of polyalphaolefin (PAO4) oil introducing oleic acid (OA)-functionalized SiC/TiN hybrid nanomaterials . The dispersion stability , wettability , thermal stability, and friction properties of the nanolubricants (NL) system were greatly improved following the application of hybrid NL. Additionally, the anti-wear and reducing-friction behavior were assessed via a four-ball tribometer. The results showed that the COF and WSD values of wear scar lubricated by hybrid NL were greatly reduced by approximately 32.7% and 35.1%, respectively, compared with the base oil. Finally, it is strongly confirmed that the significant improvement of friction performance is mainly due to improved interfacial effect of NL, the stable chemical tribo-film generated onto the friction surface , and the synergistic effect among SiC, TiN nanoparticles , and OA surfactant .
研究领域:
材料科学
·
摩擦学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2019
·
IF 3.021
Su Q. Dong,Pu K. Mi,Sheng Xu,Jun Zhang,Rui D. Zhao
In this paper, a single-component poly-α-olefin (PAO) oil base stock of an α-olefin tetramer was prepared via two-step oligomerization using a metallocene catalyst and a Ziegler–Natta catalyst in sequence. The structure was characterized, the performance was investigated, and the effects of the molecular structure and composition on performance were evaluated. First, the α-olefins were dimerized with different metallocenes as the catalyst, and the effects of the oligomerization conditions (amount of catalyst, temperature, and ratio of Al/Zr) on the molecular weight distribution of the obtained polymers were investigated. The dimerization selectivity reached 83.1%, and the content of branched α-olefin was 91.7%. In the second step, the obtained α-olefin dimer was polymerized by a Ziegler–Natta catalyst, and the dimerization reaction was dominant. A PAO with a tetramer content of 89.6% was obtained, and at 100 °C, the kinematic viscosity was 6.4 cSt and the viscosity index was 148. Further results suggested that both molecular structure parameters (the length of the main chain and the length of the branches) affect the PAO properties when the number of branches and the branch position on the molecular skeleton are the same. It was also found that, as the length of the main chain and the length of the branches increased, the kinematic viscosity and viscosity index increased, while the pour point decreased; however, when the length of the main chain, the number of branches, and the length of the branches were the same, the presence of quaternary carbons in the main chain lowered the viscosity index and increased the pour point.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2025
·
IF 3.7
Yaqi Fu,Siyu Mao,Tianyue Liao,Wei Feng
The enzyme OleT can utilize H 2 O 2 as the co-substrate, and this biocatalysis is an H 2 O 2 -driven enzymatic catalysis. In this work, OleT was recombinated by being fused to an elastin-like polypeptide (ELP). The recombinant enzyme OleT-ELP exhibits higher stability and resistance to H 2 O 2 interference compared to native OleT. OleT-ELP showed improved catalytic efficiency in producing α-olefins via fatty acid decarboxylation. The recombinant 5-hydroxymethylfurfural oxidase ( HMFO-ELP) catalyzes the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), generating H 2 O 2 as a byproduct. Combining OleT-ELP with HMFO-ELP enabled simultaneous conversion of fatty acids and HMF. The in situ H 2 O 2 generated by HMFO-ELP was transferred to OleT-ELP, enhancing catalytic efficiencies for both α-olefins and FDCA production.
研究领域:
生物化学
·
酶工程
·
绿色化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）