128 research outputs found
The lead tetra-acetate oxidations of some N-arylaminofumarates in the presence of trifluoroacetic acid
p-Chloroanilino-, p-acetylanilino-, and p-toluidinojumarates are oxidized by lead tetraacetate
in low yields to give oxanzlate. Similar oxidation of p-acetylan Nnofumarate in the presence of
trifluoroacetic add affords only oxanilate. p- Toluidino and p-chloroanilinojumarates with lead
tetra-acetateltrifluoroacetic acid give mixtures of oxazin, azobenzene and anzlide
Biological Activity of Some Malaysian Plant Extracts
Extracts obtained from three Malaysian Labiatae plants, including Ocimum sanctum, Mentha
arvensis and Orthoshiophon staminea, were investigated for their biological activity. The volatile fraction
of each plant was isolated and the major components were characterized by gas chromatography (GC),
gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR). The antibacterial
and antifungal activity, insecticidal activity and inhibition of the germination of seeds of the
volatile fraction and residue were studied
Pemprosesan Kimia ke atas Buangan Pertanian Padi
The production process of 2-furaldehyde (furfural) from agricultural wastes including the husk,
leaf and straw was investigated chemically. Three types of pro tic acid were tested with respect to its
cataly tic activity. The effect of hydrochloric acid concentration on the yield percentage was also
investigated
Toxicity Studies of Plant Extracts on Insects and Fish
Toxicity studies of several local plant extracts on insects and fish were carried out. The volatile fraction of some of
plant extracts was isolated and the major components were characterized. The contact insecticidal activity and the
toxicity test of the plant extract on fishes were studied
Chemical Conversion of the Oil Palm Wastes
The production of a 2-furaldehyde (furfural) from mesocarp fibre waste and oil palm sludge from a
palm oil mill using protic acids was investigated. The effect of immersion of fibre in acid prior to heating
was also studied. Production of furfural was completed in 3-4 hours when hydrochloric (HCI) or sulfuric
(H2S04 ) acids were used as the catalyst whereas a longer reaction time was required in the case of phosphoric
(H3P04 ) or oxalic (H2C20 4 ) acids. The experiment showed that the rates of furfural production
were increased when higher acid concentrations were applied. Immersion of fibre in the acids for 24 hours
prior to reaction increased the furfural yield. The chemical conversion of sludge from the palm oil mill
was also investigated. A similar acid concentration effect on the rate was observed
Development of microwave system for extraction of essential oils from Mesua ferrea L. leaves and Jasminum samhac flowers
A microwave extraction system (MES) was developed for the extraction of essential oils from Mesua ferrea L. leaves and Jasminum sambac flowers. The performance of MES was compared with the conventional extraction method (CEM) for dry distillation (DD), wet distillation (WD), hydro distillation (HD) and steam distillation (SD) in terms of rapidity, quality and quantity of yield and its efficiency. Mesua ferrea L. extracted by HD contributed 0.035% of yield, WD 0.029%, DD 0.024% and SD 0.013%. For Jasminum sambac, DD contributed 0.10%, WD 0.06% while SD and HD both contributed 0.02%, respectively. Although more compounds were detected in CEM extract, substantial higher amounts of odoriferous compounds were present in MES extract. The project has successfully proved that MES is more efficient than CEM in terms of rapidity, quality and quantity of yield
Comparison between conventional and microwave-assisted hydrodistillation methods towards extraction of essential oils from Murraya koenigii (Curry leaves)
Study on the extraction of essential oils from leaves of Murraya koenigii had been carried out by conventional hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD) methods. Time of the first oil droplet, percentage yield of the extracted oils and the chemical components of the extracted essential oils from both methods were compared. The running time for MAHD was set at one and half hour while running time for HD was 5 hours. The major components from the essential oils obtained from HD method were β-copaene (41.5%), α-selinene (10.0%) and α-humulene (8.4%). Meanwhile, major chemical components extracted from MAHD method were β-caryophyllene (19.5%), terpine-4-ol (17.6%) and linalool (9.8%). A total of 79.6% of chemical components were identified from essential oil extracted through HD method while MAHD method was 75.7%. The first oil droplet for HD method was found to be at 34 minutes and 20 minutes for MAHD method. MAHD is more preferable method for extracting essential oils from Murraya koenigii as it provides high extraction efficiency with less time taken
Investigation on the Chemical Constituents of the Leaves of Ficus elastica Roxb. and Their Antimicrobial Activity
Four known compounds (emodin, sucrose, morin and rutin) were isolated
from the leaves of Ficus elastica Roxb. The structures of the compounds were
established by spectroscopic techniques and by comparison with published
data. The compounds were screened for antimicrobial activity against two
species of bacteria, Bacillus cereus (Gram-positve) and PseuiUlmonas aeruginosa
(Gram-negative) and four species of fungi by using the disc diffusion method.
The compounds showed antibacterial activity but no antifungal activity was
observed against the tested organisms
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