scholarly journals Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions

2016 ◽  
Vol 2 (6) ◽  
pp. e1501591 ◽  
Author(s):  
Xiangqing Jia ◽  
Chuan Qin ◽  
Tobias Friedberger ◽  
Zhibin Guan ◽  
Zheng Huang
Keyword(s):  
Product Distribution ◽  
Liquid Fuels ◽  
Catalyst Structure ◽  
Molecular Weights ◽  
Selective Degradation ◽  
Mild Conditions ◽  
Cross Metathesis ◽  
Alkane Metathesis ◽  
Chemical Inertness ◽  
Energy Processes

Polyethylene (PE) is the largest-volume synthetic polymer, and its chemical inertness makes its degradation by low-energy processes a challenging problem. We report a tandem catalytic cross alkane metathesis method for highly efficient degradation of polyethylenes under mild conditions. With the use of widely available, low-value, short alkanes (for example, petroleum ethers) as cross metathesis partners, different types of polyethylenes with various molecular weights undergo complete conversion into useful liquid fuels and waxes. This method shows excellent selectivity for linear alkane formation, and the degradation product distribution (liquid fuels versus waxes) can be controlled by the catalyst structure and reaction time. In addition, the catalysts are compatible with various polyolefin additives; therefore, common plastic wastes, such as postconsumer polyethylene bottles, bags, and films could be converted into valuable chemical feedstocks without any pretreatment.

Catalytic conversion of ferrous carbonate to higher hydrocarbons under mild conditions and its application in transformation of CO2 to liquid fuels

2020 ◽  
Vol 4 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Yulv Yu ◽  
Jin Huang ◽  
Yuan Wang
Keyword(s):  
Catalytic Conversion ◽  
Liquid Fuels ◽  
Mild Conditions ◽  
Higher Hydrocarbons ◽  
Ferrous Carbonate ◽  
Long Chain

Coupling conversion of CO32− to hydrocarbons with carbonation of ferrous species by CO2 leads to the generation of long-chain hydrocarbons.

Influence of the Gas and Particle Residence Time on Fast Pyrolysis of Lignite

2006 ◽  
Vol 129 (2) ◽  
pp. 152-158 ◽  
Author(s):  
Lijie Cui ◽  
Wenli Song ◽  
Jiayuan Zhang ◽  
Jianzhong Yao ◽  
Weigang Lin
Keyword(s):  
Residence Time ◽  
Circulating Fluidized Bed ◽  
Product Distribution ◽  
Liquid Fuels ◽  
High Yield ◽  
Flash Pyrolysis ◽  
Particle Residence Time ◽  
Coal Particles ◽  
Liquid Products ◽  
Secondary Reactions

Coal resource is abundant in China, while the reserves of natural gas and petroleum are limited. Due to the rapid increase in the number of automobiles, a competitive way to produce liquid fuels from coal is urgently needed in China. A so-called “coal topping process” is under development at the Institute of Process Engineering, Chinese Academy of Sciences, from which liquid products can be obtained by flash pyrolysis in an integrated circulating fluidized bed system. In order to achieve a high yield of liquid products from high volatile coal, controlling the residence time of coal particles and produced gas may be of importance for minimizing the degree of the secondary reactions; i.e., polymerization and cracking of the liquid products. Experiments of the flash pyrolysis of coal have been conducted in an entrained bed reactor, which is especially designed to study the influence of the coal particle residence time on the product distribution. The results show that the gaseous, liquid, and solid product distribution, the gas compositions as well as the liquid compositions depend strongly on the gas and particle residence time.

A facile new procedure for the deprotection of allyl ethers under mild conditions

2000 ◽  
Vol 78 (6) ◽  
pp. 838-845 ◽  
Author(s):  
Yun-Jin Hu ◽  
Romyr Dominique ◽  
Sanjoy Kumar Das ◽  
René Roy
Keyword(s):  
Key Words ◽  
Catalytic System ◽  
Olefin Metathesis ◽  
Allyl Ether ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Allyl Ethers ◽  
Mild Conditions ◽  
Cross Metathesis ◽  
Allylic Ethers

A novel isomerization of O-allyl glycosides into prop-1-enyl glycosides was observed instead of cross-metathesis during an olefin metathesis reaction using Grubbs' ruthenium benzylidene catalyst (Cy3P)2RuCl2=CHPh (1), N-allyltritylamine, and N,N-diisopropylethylamine as necessary auxiliary reagents. In the search for a better catalytic system, it has been found that dichlorotris(triphenylphosphine)ruthenium(II), [(C6H5)3P]3RuCl2, (2) was much more efficient for the isomerization of allylic ethers. The labile prop-1-enyl group was easily hydrolyzed using HgCl2-HgO and the hemiacetals (25-32) were isolated in excellent yields (ca. 90%).Key words: allyl ether, carbohydrate, Grubbs' catalyst, isomerization, metathesis, deprotection.

scholarly journals Stable CAAC-based Ruthenium Complexes for Dynamic Olefin Metathesis Under Mild Conditions

2021 ◽  
Author(s):  
Oleksandr Kravchenko ◽  
Brian J.J. Timmer ◽  
Maurice Biedermann ◽  
Andrew Kentaro Inge ◽  
Olof Ramstrom
Keyword(s):  
Olefin Metathesis ◽  
High Stability ◽  
Room Temperature ◽  
Functional Group ◽  
Biologically Active ◽  
Dynamic Covalent Chemistry ◽  
Mild Conditions ◽  
Cross Metathesis ◽  
Potential Applications ◽  
Metathesis Catalysts

<p>A series of olefin metathesis catalysts bearing cyclic (alkyl)(amino)carbene (CAAC) ligands of varying size and steric demand has been synthesized and evaluated in ring-closing-, self-, and cross-metathesis reactions at room temperature. The catalysts were also probed for potential applications in dynamic covalent chemistry. The majority of the catalysts showed high stability, and remained active in the reaction mixtures for several days, including in methanol-based solutions. Higher temperatures could be used to control the reactivity towards sterically challenging substrates, enabling formation of tetrasubstituted olefins. The CAAC complexes exhibited remarkable functional group tolerance towards heteroaromatic and nucleophilic additives, making them potentially useful in the screening of biologically active compounds.</p>

scholarly journals Production of renewable biofuels and chemicals by processing bio-feedstock in conventional petroleum refineries

2014 ◽  
Vol 6 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Xuan Hoan Vu ◽  
Sura Nguyen ◽  
Thanh Tung Dang ◽  
Udo Armbruster
Keyword(s):  
Zeolite Y ◽  
Product Distribution ◽  
Waste Cooking Oil ◽  
Acid Sites ◽  
Liquid Fuels ◽  
Light Olefins ◽  
Pore Channel ◽  
Gaseous Products ◽  
Platform Chemicals ◽  
Petroleum Refineries

The influence of catalyst characteristics, i.e., acidity and porosity on the product distribution in the cracking of triglyceride-rich biomass under fluid catalytic cracking (FCC) conditions is reported. It has found that the degradation degree of triglyceride molecules is strongly dependent on the catalysts’ acidity. The higher density of acid sites enhances the conversion of triglycerides to lighter products such as gaseous products and gasoline-range hydrocarbons. The formation of gasoline-range aromatics and light olefins (propene and ethene) is favored in the medium pore channel of H-ZSM-5. On the other hand, heavier olefins such as gasoline-range and C4 olefins are formed preferentially in the large pore structure of zeolite Y based FCC catalyst (Midas-BSR). With both catalysts, triglyceride molecules are mainly converted to a mixture of hydrocarbons, which can be used as liquid fuels and platform chemicals. Hence, the utilization of the existing FCC units in conventional petroleum refineries for processing of triglyceride based feedstock, in particular waste cooking oil may open the way for production of renewable liquid fuels and chemicals in the near future. Bài báo trình bày kết quả nghiên cứu khả năng tích hợp sản xuất nhiên liệu sinh học và hóa phẩm từ nguồn nguyên liệu tái tạo sinh khối giầu triglyceride bằng công nghệ cracking xúc tác tấng sôi (FCC) trong nhà máy lọc dầu. Kết quả nghiên cứu cho thấy xúc tác có ảnh hưởng mạnh đến hiệu quả chuyển hóa triglyceride thành hydrocarbon. Tính acid của xúc tác càng mạnh thì độ chuyển hóa càng cao và thu được nhiều sản phẩm nhẹ hơn như xăng và các olefin nhẹ. Xúc tác vi mao quản trung bình như H-ZSM-5 có độ chọn lọc cao với hợp chất vòng thơm thuộc phân đoạn xăng và olefin nhẹ như propylen và ethylen. Với kích thước vi mao quản lớn, xúc tác công nghiệp FCC dựa trên zeolite Y ưu tiên hình thành C4 olefins và các olefin trong phân đoạn xăng. Ở điều kiện phản ứng của quá trình FCC, triglyceride chuyển hóa hiệu quả thành hydrocarbon mà có thể sử dụng làm xăng sinh học cho động cơ và olefin nhẹ làm nguyên liệu cho tổng hợp hóa dầu.

The decomposition of n -hexane II. By reaction with atomic hydrogen

1958 ◽  
Vol 243 (1235) ◽  
pp. 449-457
Keyword(s):  
Activation Energy ◽  
Atomic Hydrogen ◽  
Flow System ◽  
Product Distribution ◽  
Steric Factor ◽  
Hydrogen Atoms ◽  
Initial Product ◽  
Molecular Weights ◽  
Main Component ◽  
Product Fraction

The reaction of hexane with hydrogen atoms produced by mercury photosensitization, has been studied in a flow system at 300° C. About one-third of the products had molecular weights greater than that of hexane, and dodecane was the main component of this product fraction. Hydrogen: hexane ratios up to 55:1 were employed and in these conditions virtually all the quenching of excited mercury atoms was brought about by hydrogen. The activation energy and steric factor of the reaction C 6 H 14 + H = C 6 H 13 + H 2 are estimated at 6 kcal and 10 -4 , respectively. These values are in accord with those recently obtained for the corresponding reactions involving other n -paraffins. The initial product distribution was similar to that obtained in the mercury photosensitized decomposition of hexane and the findings suggest that products of lower molecular weight than hexane derive almost completely from thermal decomposition of hexyl radicals. ‘Atomic cracking’ appears to be of little importance at these high temperatures.

scholarly journals Effect by Diamond Surface Modification on Biomolecular Adhesion

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 865 ◽  
Author(s):  
Yuan Tian ◽  
Karin Larsson
Keyword(s):  
Covalent Binding ◽  
Theoretical Work ◽  
Bone Morphogenetic Protein 2 ◽  
Diamond Surface ◽  
Surface Termination ◽  
Molecular Weights ◽  
Morphogenetic Protein ◽  
Chemical Inertness ◽  
Arginine Glycine Aspartic Acid ◽  
Endothelial Growth Factor

Diamond, as material, show very attractive properties. They include superior electronic properties (when doped), chemical inertness, controllable surface termination, and biocompatibility. It is thus clear that surface termination is very important for those applications where the implant material is based on diamond. The present theoretical work has focused on the effect of diamond surface termination, in combination with type of surface plane, on the adhesion of important biomolecules for vascularization and bone regeneration. These biomolecules include Arginine-Glycine-Aspartic acid (RGD), Chitosan, Heparin, Bone Morphogenetic Protein 2 (BMP2), Angiopoietin 1 (AGP1), Fibronectin and Vascular Endothelial Growth Factor (VEGF). The various surface planes are diamond diamond (100)-2x1 and (111). The theoretical results show that the non-covalent binding of these biomolecules is in proportion with their molecular weights. Moreover, three groups of biomolecules were observed for both types of surface planes. The most strongly binding biomolecule was the BMP2 molecule. The smaller polypeptides (RGD, Chitosan and Heparin) formed a less strongly binding group. Finally, the biomolecules VEGF, Fibronectin and Angiopoietin showed bond strengths numerically in between the other two groups (thereby forming a third group). Moreover, the (111) surface was generally observed to display a stronger bonding of the biomolecules, as compared with the (100)-2x1 surface.

scholarly journals Preparation and Coagulation Performance of Carboxypropylated and Carboxypentylated Lignosulfonates for Dye Removal

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 383 ◽  
Author(s):  
Khatereh Bahrpaima ◽  
Pedram Fatehi
Keyword(s):  
Dye Removal ◽  
Carboxylate Group ◽  
Charge Densities ◽  
Molecular Weights ◽  
Mild Conditions ◽  
Ethyl Violet ◽  
Coagulation Performance ◽  
Carboxylate Content ◽  
Ft Ir ◽  
And Performance

In this work, 1-carboxypropyled (1-CPRLS) and 5-carboxypentyled lignosulfonates (5-CPELS) were synthesized using 2-chlorobutanoic acid and 6-chlorohexanoic acid as carboxylate group donors via SN1 and SN2 mechanisms, respectively. 1-Carboxypropyl and 5-carboxypentyl lignosulfonates with the charge densities of −3.45 and −2.94 meq g−1 and molecular weights of 87,900 and 42,400 g·mol−1 were produced, respectively, under mild conditions. The carboxylate content and degree of substitution (DS) of the 1-CPRLS product were 2.37 mmol·g−1 and 0.70 mol·mol−1, while those of 5-CPELS products were 2.13 mmol·g−1 and 0.66 mol·mol−1, respectively. The grafting of carboxypropyl and carboxypentyl groups to lignosulfonate was confirmed by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H-NMR and 13C-NMR) spectroscopies. In addition, 1-CPRLS and 5-CPELS were applied as coagulants for removing ethyl violet (EV) dye from a simulated solution, and their performance was related to their charge densities and molecular weights. Furthermore, fundamental discussion is provided on the advantages of (1) producing 1-CPRLS and (2) the superior properties and performance of 1-CPRLS to carboxyethylated lignosulfonate.

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