KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Assawasaengrat, PornsawanSubject: search.filters.subject.dimethyl ether

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Methanol dehydration to dimethyl ether over strong-acid-modified diatomite catalysts
    (2016-11-01)
    Pranee, Watcharakorn
    ;
    Neramittagapong, Sutasinee
    ;
    Assawasaengrat, Pornsawan
    ;
    Neramittagapong, Arthit
    Dimethyl ether synthesis via methanol dehydration over strong-acid-modified (with sulfuric, hydrochloric and nitric acid) diatomite (DM) catalysts was conducted in a fixed-bed reactor with elevated temperature reaction from 250 to 350°C. The modified DM catalysts were characterized by using X-ray diffraction, scanning electron microscopy, fourier transform infrared spectroscopy, fourier transform Raman spectroscopy, temperature-programmed desorption of ammonia, temperature-programmed of carbon dioxide, thermal gravimetric analysis, and solid-state 27Aluminum magic angle spinning/nuclear magnetic resonance spectroscopy. It was found that sulfuric-acid-modified DM catalyst yielded the highest DME selectivity (~99%). It was also revealed that methanol conversion depended on Al ions. The methanol conversion increased with Al<sup>(IV)</sup> but decreased with Al<sup>(V)</sup> and Al<sup>(VI)</sup>.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Dimethyl ether synthesis from methanol over diatomite catalyst modified using nitric acid treatment
    (2016-08-02)
    Pranee, Watcharakorn
    ;
    Neramittagapong, Sutasinee
    ;
    Assawasaengrat, Pornsawan
    ;
    Neramittagapong, Arthit
    Dimethyl ether synthesis from methanol over diatomite catalysts modified using nitric acid was investigated. The catalytic performance of diatomite was tested in a fixed-bed reactor under atmospheric pressure and within the temperature range of 250–350°C. It was discovered that high acidity of the catalyst yielded a higher methanol conversion rate. Moreover, it was revealed that the acidity of the catalyst surface was controlled by Al<sup>(IV)</sup> ions whereas basicity of the catalyst surface was determined by Al<sup>(V)</sup> and Al<sup>(VI)</sup> ions. From this finding, the authors were able to propose the mechanism of DME synthesis from methanol over treated diatomite.