scholarly journals Polyethylene upcycling to long-chain alkylaromatics by tandem hydrogenolysis/aromatization

Science ◽  
2020 ◽  
Vol 370 (6515) ◽  
pp. 437-441 ◽  
Author(s):  
Fan Zhang ◽  
Manhao Zeng ◽  
Ryan D. Yappert ◽  
Jiakai Sun ◽  
Yu-Hsuan Lee ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Waste Disposal ◽  
Reaction Temperature ◽  
Molecular Hydrogen ◽  
Catalytic Conversion ◽  
Weight Percent ◽  
Low Molecular Weight ◽  
Moderate Reaction ◽  
High Yields ◽  
Long Chain

The current scale of plastics production and the accompanying waste disposal problems represent a largely untapped opportunity for chemical upcycling. Tandem catalytic conversion by platinum supported on γ-alumina converts various polyethylene grades in high yields (up to 80 weight percent) to low-molecular-weight liquid/wax products, in the absence of added solvent or molecular hydrogen, with little production of light gases. The major components are valuable long-chain alkylaromatics and alkylnaphthenes (average ~C30, dispersity Ð = 1.1). Coupling exothermic hydrogenolysis with endothermic aromatization renders the overall transformation thermodynamically accessible despite the moderate reaction temperature of 280°C. This approach demonstrates how waste polyolefins can be a viable feedstock for the generation of molecular hydrocarbon products.

A family of low-molecular-weight organogelators based on long chain substituted benzoic acid hydrazides

2006 ◽  
Vol 124 (1-3) ◽  
pp. 32-36 ◽  
Author(s):  
Changhui Tan ◽  
Lihong Su ◽  
Ran Lu ◽  
Pengchong Xue ◽  
Chunyan Bao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Benzoic Acid ◽  
Low Molecular Weight ◽  
Low Molecular Weight Organogelators ◽  
Long Chain

Effects of Ultrasonic and Physical-Rays Treatment on the Molecular Structures of Poly(γ-Glutamic Acid)

2012 ◽  
Vol 518-523 ◽  
pp. 5550-5554
Author(s):  
Ming Hui ◽  
Chun Yuan Gao ◽  
Qing Tian ◽  
Xiao Bo Du ◽  
Xiang Long Yin
Keyword(s):  
Molecular Weight ◽  
Glutamic Acid ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Molecular Structures ◽  
Low Molecular Weight ◽  
Chain Molecules ◽  
Sds Page ◽  
Γ Rays ◽  
Long Chain

Molecule structures of poly(γ-glutamic acid) (γ-PGA) were modified by ultrasonic, UV and 60Co γ-rays irradiation treatments, which might be used to prepare the polymer with low molecular weight. When 10 g/l γ-PGA solution was sonicated 60 times (400W, working time 3 s and interval 4 s) or that of 20 g/l solution was irradiated from 2 kGy to 10 kGy, the long-chain molecules were broken into smaller fragments. But, as the same solution of 10 g/l was irradiated by UV rays for 10 min, the molecular aggregates were observed in the solution so that the molecular weight distribution of γ-PGA became narrower compared with the control through the analysis of SDS-PAGE. These results would have a reference of the modification of γ-PGA molecules and the production of low molecular weight γ-PGA.

Chain Extension of Poly(butylene adipate) with 2,2’-(1,4- Phenylene)-bis(2-oxazoline)

2006 ◽  
Vol 11-12 ◽  
pp. 387-390 ◽  
Author(s):  
Si Yang Luo ◽  
Yu Zhang ◽  
Jing Bo Zhao
Keyword(s):  
Molecular Weight ◽  
Influencing Factors ◽  
1H Nmr ◽  
Reaction Temperature ◽  
Chain Extender ◽  
Chain Extension ◽  
Molar Ratio ◽  
Low Molecular Weight ◽  
Melt Polycondensation

Low molecular weight poly(butylene adipate) (PBA) was synthesized by melt polycondensation. The chain extension of the prepolymers was carried out using 2,2’-(1,4-phenylene)-bis(2-oxazoline) (PBOX) as chain-extender. The influencing factors including reaction temperature, oxazoline/-COOH molar ratio, and the molecular weight of prepolymers were studied. At the optimal chain-extending condition, PBA with Mn of 38583 and Mw of 125497 was prepared. The structure of the chain-extended PBA was also characterized by the FTIR and 1H NMR.

FATTY ACIDS OF THE SEED OIL OF CARDIOSPERMUM HALICACABUM

1958 ◽  
Vol 36 (11) ◽  
pp. 1537-1540 ◽  
Author(s):  
Mary J. Chisholm ◽  
C. Y. Hopkins
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
Gas Chromatography ◽  
Seed Oil ◽  
Methyl Esters ◽  
Eicosenoic Acid ◽  
Major Fatty Acid ◽  
Low Molecular Weight ◽  
Long Chain Fatty Acids ◽  
Long Chain

The seed oil of Cardiospermumhalicacabum L., family Sapindaceae, was found to have 11-eicosenoic acid as the major fatty acid in its glycerides. In this respect it is unique among the true natural fats. The amount of eicosenoic acid in the sample examined was 42% of the total long-chain fatty acids. The identity and amounts of the principal fatty acids of the oil were determined by gas chromatography and by distillation of the methyl esters. The estimated percentages were: palmitic 3, linolenic 8, linoleic 8, oleic 22, stearic 2, eicosenoic 42, arachidic 10. In addition, there was evidence of small proportions (1–2%) of a low-molecular-weight acid and of C22 acids.

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