Catalysts
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2022
·Vol. 12
·期 1
·104
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IF 4.501
Ying Duan,Qianqian Luo,Renfeng Nie,Jianshe Wang,Yongsheng Zhang,Tianliang Lu,Chunbao Xu
The production of methyl lactate as a degradable polymer monomer from biomass was an important topic for a sustainable society. In this manuscript, glycerol was oxidated to methyl lactate catalyzed by the combination of Au-CuO and Sn-Beta. The influence of Sn content, Sn source, and the preparation conditions for Sn-β was studied. The Au content in Au/CuO was also investigated by varying the Au content in Au/CuO. The catalysts were characterized by XRD, FTIR spectroscopy of pyridine adsorption, and TEM to study the role of Sn and the influence of different parameters for catalyst preparation. After the optimization of reaction parameters, the yield of methyl lactate from glycerol reached 59% at 363 K after reacting in 1.6 MPa of O2for 6 h.Keywords:glycerol;oxidation;methyl lactate;Sn-Beta;Au/CuO
研究领域:
催化化学
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生物质转化
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可持续化学
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产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
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2024
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IF 6.3
Qiuyang Liu,Rulin Yang,Bingzhe Dong,Hongguang Sun,Guangqiang Xu,Qinggang Wang
The depolymerization of waste plastics into high-value products is a promising solution to address the plastic crisis. Among this field, catalytic activity and selectivity of depolymerization catalyst are of great concerns. Accordingly, in this work, a simple catalytic system was explored in detail to achieve the fast and selective chemical recycling of PLA into methyl lactate. Using commercially available M[bis(trimethylsilyl)amide] (MHMDS, M = Li, Na, K) as catalysts, the depolymerization of PLA was completed within a few minutes at room temperature. The selectivity and optical purity of the depolymerized product methyl lactate are greater than 99 %. The effect of conditions such as metal center, catalyst form, and solvent on depolymerization was investigated. Moreover, the gram-grade depolymerization, selective depolymerization of blended or mixed PLA plastic, and the recyclability of catalyst were further explored. This work accomplishes the path of highly selective and active depolymerization of PLA under mild conditions, thereby promoting sustainable development of PLA.
研究领域:
材料科学
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环境科学
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化学工程
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产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
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2022
·
IF 4.778
Xiaomei Yang,Xu Chen,Bin Lv,Yunlai Su,Lipeng Zhou
Sn-Beta zeolite is an excellent catalyst for the transformation of biomass derived carbohydrates. However, the long synthesis time restricted its application. Here, alkaline (earth) salt was used as promoter to accelerate the crystallization of Sn-Beta. Different alkaline (earth) salts and the amount of MgCl 2 were investigated. The properties of the synthesized samples were characterized by various techniques and compared with Sn-Beta, and the catalytic performance was investigated for the conversion of glucose to methyl lactate (MLA). The results indicate that a small amount of alkaline (earth) salt, especially MgCl 2 , promoted dramatically the crystallization of Sn-Beta. The full crystallization time was shortened from 15 d to 5 d with the aid of MgCl 2 ( n Mg / n Sn of 1.0) for Sn-Beta with n Si / n Sn of 100. Sn 4+ cations were incorporated into the framework sites, while Mg 2+ cations replaced the protons of silanol defects. Mg–Sn-Beta with strong Lewis acid sites and less silanols showed high activity and selectivity for glucose conversion to MLA. The yield of MLA is 20% over the fully crystallized Sn-Beta at 120 °C for 15 h and glucose concentration of 3.1 wt%, which increased significantly to 44% over the fully crystallized 1 Mg–Sn-Beta. Furthermore, Mg–Sn-Beta is stable and recyclable.
研究领域:
催化化学
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生物质转化
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DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
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2024
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IF 4.7
Yingdan Ye,Han Wang,Yibin Zhang,Huaiyuan Zhao,Weichen Du,Ping Chen,Zhaoyin Hou
Chemical upcycling of end-of-life plastics is an economically and environmentally feasible way to tackle plastics crisis. Among them, methanol alcoholysis of polylactic acid (PLA) is a promising approach, which can produce methyl lactate (MLA) that can be further converted to lactide to achieve a sustainable development. In this work, a series of WO x /ZrP catalysts with WO x active sites in low coverage and high surface area were synthesized via anchoring WO x species on the surface of zirconium phosphate (ZrP). Characterizations indicated that the strong interaction between WO x and ZrP promoted the formation of WO x active sites in low coverage. In particular, 10 %WO x /ZrP catalyst was highly active and stable for the alcoholysis of PLA plastics under mild conditions due to the abundant WO x active sites and strong acidity. The yield of MLA over 10 %WO x /ZrP catalyst reached 94.5 % within 4 h at 160 °C, which was superior to the performance of traditional solid acids ( α -ZrP, HZSM-5, H β and Amberlyst-45). In addition, 10 %WO x /ZrP was versatile for the alcoholysis of discarded PLA-based products and could be recycled at least five times. The prominent performance of 10 %WO x /ZrP catalyst and the possible reaction mechanism were discussed.
研究领域:
化学工程
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环境科学
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材料科学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
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2020
·Vol. 10
·期 24
·8437-8444
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IF 5.721
Xiaomei Yang,Liuyong Wang,Tianliang Lu,Beibei Gao,Yunlai Su,Lipeng Zhou
Hydrothermally synthesized Sn-Beta is an excellent catalyst for the conversion of sugars to alkyl lactates. However, its catalytic performance is highly dependent on the synthesis parameters. In this work, the effects of the synthesis parameters such as the water amount of the synthesis gel and the crystallization time on the synthesis and properties and catalytic performance of Sn-Beta in the conversion of glucose to methyl lactate (MLA) were investigated. The crystallization rate was accelerated remarkably by reducing the water amount of the synthesis gel. With the aid of the Si-Beta seed, Sn-Beta was almost fully-crystallized after one day with nH2O/nSiO2 of 4.5, but seven days were needed with nH2O/nSiO2 of 7.5. However, Sn-Beta synthesized with nH2O/nSiO2 of 4.5 has more extraframework SnO2 due to the fast formation of the *BEA structure and the slow incorporation of Sn4+ into the framework sites, which resulted in the lower activity of MLA formation. More Sn4+ species were incorporated into the framework sites and thus more Lewis acid sites were generated with increasing crystallization time. At the same time, the ratio of open to closed Sn sites (RO/C) increased, which led to the decrease in the activity of MLA formation and due to that, the open Sn site with a proximal silanol is unfavorable for the conversion of glucose to MLA. During recycling study, it is surprisingly found that the yield of MLA increased gradually over the fully-crystallized Sn-Beta catalyst. Characterization results of the recovered catalyst from the eighth run indicate that the structure was preserved well, but the value of RO/C reduced due to the change of the state and microenvironment of Sn species.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2024
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IF 6.5
Shengqiang Zhou,Tianliang Lu,Lipeng Zhou,Xiaomei Yang
Au/Sn-zeolite catalysts showed high activity for selective conversion of glycerol to methyl lactate, but suffered from poor stability under the reaction conditions in our previous report (ACS Catal. 2017, 7, 7274). Encapsulation of Au nanoparticles within zeolite is a promising strategy to enhance their stability in catalytic reaction. Herein, one-pot synthesis of Au@Snβ was achieved by a mercaptosilane-assisted hydrothermal synthesis method. The protocol involves crystallization of Snβ synthesis gels around coordinated Au precursors, resulting in Snβ framework constraining Au coordination complexes. The confinement of small (∼2.89 nm) and uniform Au particles within Snβ was achieved. The bifunctional catalyst composed of oxidative sites (Au) and Lewis acid sites (Sn) gave 77.3 % methyl lactate (MLA) yield from the base-free selective conversion of glycerol (GLY). The TOF value of Au@Snβ was higher than that of Au/Sn-zeolite in our previous report. Moreover, the special structure protects Au nanoparticles from sintering or agglomeration and improves the stability and recyclability in selective oxidation of GLY to MLA.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2021
·Vol. 96
·期 8
·2238-2248
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IF 3.174
Xiao-Yang Yue,Hui-Fang Ren,Chengming Wu,Jun Xu,Jifan Li,Chun-Ling Liu,Wen-Sheng Dong
BACKGROUND Methyl lactate is widely applied in the chemical, food, cosmetics and pharmaceutical industries. The conversion of carbohydrates over heterogeneous catalysts to methyl lactate is a promising environmentally benign process. RESULTS Hierarchical Sn-Beta zeolite (Sn-Beta) and corresponding bimetal-doped Beta zeolites (M-Sn-Beta; M = Zn, In, La, Ga, Ni) were prepared via a novel modified hydrothermal synthesis method to convert carbohydrates into methyl lactate. The introduction of Zn into Sn-Beta considerably improved the yield of methyl lactate from glucose, while for the catalysts containing In, La, Ga and Ni, such improvements were not observed. CONCLUSIONS A methyl lactate yield reaching up to 66.7% was obtained over Zn-Sn-Beta at 220 °C for 6 h. The enhanced catalytic performance was attributed to high Lewis acid density and strength, together with synergistic effects between framework Sn 4+ and Zn 2+ ions of Zn-Sn-Beta. Additionally, Zn-Sn-Beta demonstrated fructose and sucrose conversion into methyl lactate with yields of 68.4% and 70.0%, respectively. The Zn-Sn-Beta catalyst could be re-used at least five times with only a slight loss of methyl lactate yield. © 2021 Society of Chemical Industry (SCI).
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
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2021
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IF 4.094
Shengqiang Zhou,Lipeng Zhou,Yunlai Su,Xiaomei Yang,Hao He
Sn-Beta zeolite is a promising heterogeneous Lewis acid catalyst. Hydrothermal synthesis of Sn-Beta(TEOS) using tetraethyl orthosilicate (TEOS) as silica source is a classical method. However, the hydrolysis of TEOS generates considerable ethanol, which is unfavorable for scalable production of Sn-Beta. Herein, cheap fumed silica and silica sol were used as Si sources to synthesize Sn-Beta and compared with that synthesized from TEOS . The crystalline phase, morphology, physicochemical properties, and the state of Sn were characterized. It was found that Sn-Beta can be successfully prepared with fumed silica and silica sol as well as TEOS as silica source. Sn was introduced into the framework of these samples. Sn-Beta synthesized from fumed silica (Sn-Beta(FS)) and silica sol (Sn-Beta(Sol)) had similar crystallization behavior and full crystallization time as well as morphology, crystal size with that from TEOS. Sn-Beta(Sol) has less silanols and lowest ratio of open/closed tin site among these samples. It exhibited higher catalytic activity for the conversion of glucose to methyl lactate and lower catalytic activity for the isomerization of glucose as compared with the other two samples. Sn-Beta(FS) showed similar catalytic performance in the studied reactions with Sn-Beta(TEOS).
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 95
·期 3
·798-805
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IF 2.659
Dan Luo,Shengnan Liu,Wang Yin,Shuqian Xia
BACKGROUND Fast pyrolysis of lignocellulosics has provided an abundant sugar source for production of value-added chemicals, and levoglucosan is the most representative sugar in pyrolysis liquid (bio oil). This paper explored the potential for producing methyl lactate from levoglucosan by employing the mixed catalysts of zeolite tin beta (Sn-Beta) and zeolite hydrogen beta (H-Beta). RESULTS Under the optimal conditions (at 200 °C and mixed catalysts with H-Beta:Sn-Beta ratio of 1:5), the yield of methyl lactate obtained from levoglucosan conversion was as high as 35%. And the yield was comparable to that of methyl lactate obtained from glucose conversion under the similar conditions (at 200 °C and pure Sn-Beta). In order to investigate the reason, a contrasting experiment with glucose as substrate also was carried out with the mixed catalysts. The results indicated that during the levoglucosan conversion process, ‘the methanolysis of levoglucosan’ was likely to compete with ‘the dehydration of glucose’ for the Brønsted acid sites of H-Beta. In addition, the catalytic functions of H-Beta and Sn-Beta, and the reaction pathway were deeply investigated through tracking and comparing the conversion of levoglucosan over mixed H-Beta/Sn-Beta and over pure Sn-Beta catalysts, respectively. CONCLUSION The appropriately lower ratio of H-Beta:Sn-Beta and relatively higher temperature were favorable for the reaction. H-Beta containing Brønsted acid could remarkably accelerate the conversion of levoglucosan and methyl-glucosides to glucose. Sn-Beta containing Lewis acid mainly promoted the retro-aldol condensation of glucose and formation of methyl lactate. © 2019 Society of Chemical Industry
研究领域:
化学工程
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生物质能
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催化化学
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DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 94
·期 6
·1958-1967
·
IF 2.659
Jifan Li,Duo Li,Chun-Ling Liu,Chunli Xu,Wen-Sheng Dong
BACKGROUND Glycerol is a versatile platform compound to produce valuable chemicals. One-pot direct conversion of glycerol into methyl lactate with methanol as solvent is very attractive, because it can reduce intermediate steps and avoid the separation of glycerol/methanol mixtures. RESULTS A series of tin (Sn)-exchanged montmorillonite(M)-supported Au catalysts were prepared by a combination of ion exchange and colloidal deposition methods, and designed as bifunctional catalysts containing gold (Au) and solid acid. These catalysts were employed for one-pot conversion of glycerol to methyl lactate in methanol. The Au/Sn(20)-Mt catalyst gave a high yield of methyl lactate of 54% upon conversion of 0.25 mol L –1 glycerol methanol solution over 0.07 g catalyst at 210 °C under 3 MPa air for 5 h. The good performance of Au/Sn(20)-Mt was ascribed to the coexistence of small Au particle and abundance of acid sites. The glycerol conversion remained almost unchanged in the five recycled runs, whereas the methyl lactate yield decreased after the first run but kept stably in the later four catalytic runs. CONCLUSIONS Among the series of Sn-exchanged Mt-supported Au catalysts, Au/Sn(20)-Mt showed the highest glycerol conversion and methyl lactate yield. Containing both small Au particles and having an abundance of acid sites contributed to the excellent catalytic activity of Au/Sn(20)-Mt. © 2019 Society of Chemical Industry
研究领域:
化学工程
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
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2014
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IF 3.679
Lipeng Zhou,Lin Wu,Hongji Li,Xiaomei Yang,Yunlai Su,Tiangliang Lu,Jie Xu
A facile and efficient method to improve the selectivity of methyl lactate (MLA) in the chemical conversion of glucose in methanol catalyzed by homogeneous Lewis acid was established. The yield of MLA was efficiently improved through controlling the acidity of the reaction solution by neutralization of protons generated from the hydrolysis/methanolysis of SnCl 4 . The mechanism of glucose conversion to MLA catalyzed by SnCl 4 -NaOH was explored. The effects of the concentration of catalyst and substrate and the reaction temperature and time were systematically studied. The catalyst system of SnCl 4 -NaOH can efficiently convert glucose, fructose, and sucrose to MLA with yields of 47%, 57%, and 51% at 160 °C for 2.5 h, respectively. The catalyst can be regenerated and reused at least three times in the conversion of glucose to MLA without significant loss of activity and selectivity.
研究领域:
化学工程
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催化化学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
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IF 7.632
Bo Tang,Shuang Li,Wei-Chao Song,En-Cui Yang,Xiao-Jun Zhao,Naijia Guan,Landong Li
In this work, BEA-type hierarchically structured stannosilicate zeolite Sn-Beta-H was developed, which involved alkali-induced degradation of all-silica Beta (Si-Beta) and self-assembly of the resultant Si-Beta fragments with SnCl2·2H2O in the hydrothermal condition templated with tetraethylammonium hydroxide (TEAOH) and polydiallydimethylammonium chloride (PDADMAC). The synthesized Sn-Beta-H zeolite was comprehensively characterized by means of XRD, N2 physisorption, TEM, UV–vis, XPS, TG, DRIFT, and FTIR spectroscopy with pyridine and deuterated acetonitrile adsorption. The Lewis acidity related to isolated tetrahedrally coordinated Sn species in the hierarchical porous Beta framework was revealed, which existed in the form of partially hydrolyzed and framework-integrated species. The Sn-Beta-H zeolite worked efficiently in the catalytic transformation of a series of carbohydrates into methyl lactate, outperforming the microporous Sn-Beta and postsynthesized mesoporous meso-Sn-Beta counterparts. The influence parameters such as mesoporosity, hydrophilicity/hydrophobicity, and Lewis acidity on the glucose conversion were studied in detail.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）