排序方式: 共有8条查询结果,搜索用时 0 毫秒
1
1.
Pumtang S Siripornnoppakhun W Sukwattanasinitt M Ajavakom A 《Journal of colloid and interface science》2011,364(2):366-372
A well known unique property of polydiacetylenes (PDAs) is the colorimetric response to external stimuli making it one of the most studied conjugated polymers for sensing applications. Here we report the synthesis of a novel series of diacetylene acids from the condensation of pentacosa-10,12-diynylamine (PCDAmine) and dicarboxylic acid or its anhydrides. One of these diacetylene lipids, 4-(pentacosa-10,12-diynylamino)-4-oxobutanoic acid (PCDAS), is used in combination with pentacosa-10,12-diynoic acid (PCDA) for dropcasting on pieces of filter paper which are consequently irradiated by UV light to generate a paper based sensor array for solvent detection and identification. Upon the exposure to various types of organic solvents, the blue colored sensors colorimetrically respond to give different shades of colors between blue to red. The color patterns of the sensor array are recorded as RedGreenBlue (RGB) values and statistically analyzed by principal component analysis (PCA). The PCA score plot reveals that the array is capable of identifying eleven common organic solvents. 相似文献
2.
Porntip Luangrujiwong Anawat Sungpet Ratana Jiraratananon J. Douglas Way 《Journal of membrane science》2005,250(1-2):277-282
Single-component facilitated transports of ethylbenzene, styrene, cyclohexene and 1-hexene were carried out using the feed concentrations ranging from 0.5 M to pure. Equilibrium constants of the Ag+-solute complex formation, determined by distribution method, were 0.7, 2.2, 32.0, 129.1 M−1, respectively. Carrier saturation was not found with the membrane incorporated with 2.67 M Ag+-ion. As the carrier concentration was reduced to 0.51 M, increase in the feed concentration beyond 4.5 M had very little effect on ethylbenzene flux, suggesting the onset of carrier saturation. Styrene and cyclohexene underwent the carrier saturation when the carrier loading was 0.25 M, while a complete saturation was not observed with 1-hexene. Extraction of solute from the membranes revealed that less than 50% of Ag+-ions were occupied when the carrier saturation occurred. It was also found that the ability of solute to use available Ag+-ions in the membrane was dependent on the equilibrium constant. 相似文献
3.
Treatment of oxidized cellulose fabric with chitosan and its surface activity towards anionic reactive dyes 总被引:5,自引:1,他引:4
Yupaporn Kitkulnumchai Anawat Ajavakom Mongkol Sukwattanasinitt 《Cellulose (London, England)》2008,15(4):599-608
The surface modification of cellulose fabric with chitosan was achieved through an oxidation of the fabric with KIO4 followed by reductive ammination with chitosan. The chitosan content in the fabric determined by Kjeldahl nitrogen analysis
technique was 1.69%. The scanning electron micrograph revealed submicron particles of chitosan attached on the fabric surface.
Dyeing of the modified fabrics with mono-chloro-triazine and vinyl sulfone anionic reactive dyes, showed vastly improved exhaustion
and color yield (K/S) indicating that this method of surface modification is effective for changing surface activity of the
fabric. The enhancement of the dye uptake brought about an improved dyeing process in which the dye and salt used could be
reduced by half and 14%, respectively. A Significant drop in burst strength upon the oxidation but no discernable adverse
color fastness property was observed for the chitosan-modified fabric. 相似文献
4.
Thirawat Sirijindalert Kunlayanee Hansuthirakul Paitoon Rashatasakhon Mongkol Sukwattanasinitt Anawat Ajavakom 《Tetrahedron》2010,66(27-28):5161-5167
The reactions of Boc-β-amido- and β-amino acrylates, in which the CC possesses both nucleophilic and electrophilic sites, were investigated under acidic conditions. The trifluoroacetic-acid induced cyclization of the β-amido acrylates to the corresponding oxazolidin-2-ones involves a rarely seen nucleophilic attack of the carbamate carbonyl group. The cyclotrimerization of β-amino acrylates to N-substituted 1,4-dihydropyridines was observed in the presence of a Lewis acid. High yields of 1,4-dihydropyridines (70–83%) were readily obtained by using substoichiometric amount TiCl4 under mild condition. The cyclotrimerization is presumably occurring via a Hantzsch related mechanism involving three addition/elimination reactions of the amphiphilically reactive CC. 相似文献
5.
Daranee Homraruen Thirawat Sirijindalert Luxsana Dubas Mongkol Sukwattanasinitt Anawat Ajavakom 《Tetrahedron》2013,69(5):1617-1621
Novel 1,4-dihydropyridine (DHP) derivatives containing 3 carboxylic acid units are synthesized via cyclotrimerization of N-substituted β-aminoacrylates followed by basic hydrolysis of the triester. These DHP derivatives are readily soluble in aqueous media buffered at pH 8.0 and the solutions give blue fluorescent signals with quantum yields of 7–23%. One of these compounds, bearing a p-methoxyphenyl N-substituted group, shows specific fluorescent quenching with the mercuric ion (Hg2+). The fluorescent signal of the DHP derivative decays over a period of minutes to hours depending on the Hg2+ concentration, which implies that the sensing mechanism involves chemical reaction between the Hg2+ ion and the DHP compound. The 1H NMR and MS data suggest that Hg2+ mediates the oxidation of the DHP ring into a pyridinium ring. The event is useful for fluorescent detection of Hg2+ at the micromolar level within 30 min, with a detection limit of 0.2 μM in aqueous medium. 相似文献
6.
Waroton Paisuwan Thanakrit Chantra Paitoon Rashatasakhon Mongkol Sukwattanasinitt Anawat Ajavakom 《Tetrahedron》2017,73(24):3363-3367
A novel synthetic pathway towards the 2-oxazolidinone derivatives involving the halo-induced cyclisation of tert-butyl allyl(phenyl)carbamate was successfully developed. Various halogenating reagents were evaluated under different reaction conditions for the reaction optimisation. Interestingly, the synthetic route to 2-oxazolidinone derivatives containing one halogen atom in the aliphatic site or two halogen atoms including the extra halogen atom substituted in the aryl group at the para position, were thoroughly established for all chloro-, bromo- and iodo compounds. Either halo-unsubstituted-aryl oxazolidinone or p-halo-substituted-aryl oxazolidinone could be selectively produced by selecting the appropriate choices of halogenated reagents and reaction conditions e.g. reaction time and temperature. Toloxatone, a commercial antidepressant, was successfully synthesized by using this developed method. 相似文献
7.
Inside Cover: Reaction Mechanism of Methanol to Formaldehyde over Fe‐ and FeO‐Modified Graphene (ChemPhysChem 5/2015) 下载免费PDF全文
8.
Anawat Thivasasith Dr. Jakkapan Sirijaraensre Dr. Pipat Khongpracha Dr. Chompunuch Warakulwit Dr. Bavornpon Jansang Prof. Dr. Jumras Limtrakul 《Chemphyschem》2015,16(5):986-992
We employed periodic DFT calculations (PBE‐D2) to investigate the catalytic conversion of methanol over graphene embedded with Fe and FeO. Two possible pathways of dehydrogenation to formaldehyde and dehydration to dimethyl ether (DME) over these catalysts were examined. Both processes are initiated with the activation of methanol over the catalytic center through O?H cleavage. As a result, a methoxo‐containing intermediate is formed. Subsequently, H‐transfer from the methoxy to the adjacent ligand leads to the formation of formaldehyde. Conversely, the activation of the second methanol over the intermediate gives DME and H2O. Over Fe/graphene, the dehydration process is kinetically and thermodynamically preferable. Unlike Fe/graphene, FeO/graphene is predicted to be an efficient catalyst for the dehydrogenation process. Oxidative dehydrogenation over FeO/graphene takes place through two steps with free energy barriers of 5.7 and 10.2 kcal mol?1. 相似文献
1