Environmentally Benign Route for the Synthesis of Polycarbonate Diols (PCDLs)−Calcined MgAl Hydrotalcites as Heterogeneous Catalysts

2008 ◽  
Vol 47 (7) ◽  
pp. 2140-2145 ◽  
Author(s):  
Yue Xia Feng ◽  
Ning Yin ◽  
Qi Feng Li ◽  
Jun Wei Wang ◽  
Mao Qing Kang ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Environmentally Benign

A facile approach to fabricate halloysite/metal nanocomposites with preformed and in situ synthesized metal nanoparticles: a comparative study of their enhanced catalytic activity

2015 ◽  
Vol 44 (19) ◽  
pp. 8906-8916 ◽  
Author(s):  
Sankar Das ◽  
Subhra Jana
Keyword(s):  
Catalytic Activity ◽  
Comparative Study ◽  
Metal Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Cost Effective ◽  
Environmentally Benign ◽  
Metal Nanocomposites

Halloysite/metal nanocomposites have been synthesized through the immobilization of preformed and in situ synthesized metal nanoparticles over halloysite surfaces, which in turn produce efficient, cost-effective, and environmentally benign heterogeneous catalysts.

Biodiesel Production Using Mixed Solid Catalysts

2013 ◽  
Vol 824 ◽  
pp. 451-458
Author(s):  
A.K. Temu
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Biodiesel Production ◽  
Environmentally Benign ◽  
Catalyst Loading ◽  
Yield Data ◽  
Continuous Processes ◽  
Solid Catalysts ◽  
Base Catalysts ◽  
Astm D6751

One of the disadvantages of homogeneous base catalysts in biodiesel production is that they cannot be reused or regenerated because they are consumed in the reaction. Besides, homogeneous catalysed process is not environmentally friendly because a lot of waste water is produced in the separation step. Unlike homogeneous, heterogeneous catalysts are environmentally benign, can be reused and regenerated, and could be operated in continuous processes, thus providing a promising option for biodiesel production. This paper presents catalytic activity of single and mixed solid catalysts in production of biodiesel from palm oil using methanol as well as ethanol at atmospheric pressure. The catalysts used are CaO, K2CO3, Al2O3, and CaO/K2CO3, CaO/Al2O3, K2CO3/Al2O3 mixtures. Results show that methanol is a better reactant with biodiesel yield ranging from 48 to 96.5% while ethanol gives yields ranging from 20 to 95.2%. The yield data for single catalysts range from 20 to 89.2% while that for mixed catalysts range from 52 to 96.5% indicating improvement in the activity by mixing the catalysts. The study also shows that biodiesel yield increases with catalyst loading which emphasizes the need for sufficient number of active sites. The properties of biodiesel produced compares well with ASTM D6751 and EN 14124 biodiesel standards.

Advances in the Synthesis of Xanthenes: An Overview

2018 ◽  
Vol 15 (3) ◽  
pp. 341-369 ◽  
Author(s):  
Ankita Chaudhary ◽  
Jitender M. Khurana
Keyword(s):  
Heterogeneous Catalysts ◽  
Biological Activities ◽  
Reaction Times ◽  
Environmentally Benign ◽  
Central Nucleus ◽  
Diversity Oriented Synthesis ◽  
Wide Range ◽  
Privileged Scaffold ◽  
Synthetic Methodologies ◽  
Reaction Media

Background: Xanthene is pharmacologically important oxygen containing heterocyclic moeity exhibiting an array of potent biological activities like antibacterial, antiviral, antiinflammatory, antitumor, antioxidant, antiplasmodial etc. Other useful applications of these heterocycles are as fluorescent materials for the visualization of biomolecules and in laser technology. Objective: This review gives an insight of the literature available on the methods for the construction of xanthene nucleus. This review article can be reasonably encouraging for those involved in the synthesis of molecules exhibiting a wide range of biological activities involving xanthene as central nucleus and would provide them assistance in developing new eco-friendly, efficient and economical viable methods. Conclusion: Owing to diverse applications of xanthenes, various synthetic methodologies have been developed, whether to construct this privileged scaffold. Many of the reported methods involve the use of various harsh catalysts/reagents that are not environmentally benign, produce a large amount of waste and need longer reaction times. The sustainable and diversity oriented synthesis of xanthene scaffold which incorporates Green Chemistry tools like multicomponent reaction approach, heterogeneous catalysts, alternate reaction media such as water, ionic liquids, polyethylene glycol etc. has also been developed.

scholarly journals Synthesis of activated carbon sand their application in the synthesis of monometallic and bimetallic supported catalysts

2020 ◽  
Vol 5 (4) ◽  
pp. 190-196
Author(s):  
DALILA BOUSBA ◽  
CHAFIA SOBHI ◽  
AMNA ZOUAOUI ◽  
SOUAD BOUASLA
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Bimetallic Catalyst ◽  
Activated Carbons ◽  
Supported Catalysts ◽  
Chemical Properties ◽  
Environmentally Benign ◽  
Organic Transformations ◽  
Long Time ◽  
Physical And Chemical

Biomass-derived porous carbons are attractive materials for the synthesis of carbon-supported catalysts, carbonaceous catalysts are environmentally benign and could provide an important competitive advantage as compared to existing heterogeneous catalysts, however the surface properties of carbon materials and excellent physical and chemical properties are compatible with diverse catalysis reactions including organic transformations. Currently, activated carbons are one of well known carbonaceous materials for their catalytic properties and for use as support in heterogeneous catalysis. The supported catalysts have been successfully used in the chemical industries for a long time, in which carbon supported catalysts have allowed to a new chemical catalytic process, on the other hand Heterogeneous catalysis plays a key role in the manufacture of essential products in different fields. In this paper, we present a comparative study, between two main different methods for activated carbons (ACs) preparation namely, physical and chemical activations. Latter was prepared from agro-industrial biomass and used as a support to prepare monometallic (dry impregnation and excess impregnation) and bimetallic catalyst (successive impregnation and co impregnation).

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