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Assessing farmers’ adoption of ethylene stimulation in increasing Para rubber production in Ban Khai District, Rayong Province
(2023-07-01)
Orsuwan, W.
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Suwanmaneepong, S.
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Llones, C.
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Khuhaswanvej, S.
The study found that only 50 percent of the trained rubber farmers have adopted the use of ethylene stimulation. Several factors that contributed to non-adopters’ hesitance are perceived uncertainties of technology attributes, cost of implementation, and farmers’ attitudes. From these factors, the increasing cost was the recurring reason expressed by farmers during the focus group discussion. Furthermore, a review of related studies revealed that there was an inadequate R&D investment in the rubber industry. Therefore, government supported in boosting the R&D of the country’s rubber industry would require an immediately action and implementation that competed to rubber export countries for rapidly gaining in the competition.
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Selective acetylene removal from ethylene-rich feed by cross-metathesis over supported WO3 catalysts
(2023-01-25)
Promchana, Pratya
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Choojun, Kittisak
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Limphirat, Wanwisa
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Poo-arporn, Yingyot
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Sooknoi, Tawan
Acetylene in ethylene-rich feed can be removed via acetylene/ethylene cross-metathesis over WO<inf>3</inf>-supported catalysts at 450 °C, yielding 1,3-butadiene with cyclohexene as a minor product. The catalyst must be treated with ethylene at 600 °C to generate a genuinely active site of tungsten (IV) alkylidene species (W=CH<inf>2</inf>). The H<inf>2</inf> treatment decreases surface W[dbnd]O concentration, and hence the activity. Raman spectroscopy shows that active single-site WO<inf>3</inf> species, including mono oxo-WO<inf>3</inf> ((O=)W(O-Si)<inf>3</inf> and (O=)W(O-Si)<inf>4</inf>) and dioxo-WO<inf>3</inf> species (O=)<inf>2</inf>W(O-Si)<inf>2</inf>) were generated in 2%WO<inf>3</inf>/SiO<inf>2</inf>, while the WO<inf>3</inf> cluster and bulk WO<inf>3</inf> exist in 3–5%WO<inf>3</inf>/SiO<inf>2</inf> and 7%WO<inf>3</inf>/SiO<inf>2</inf>, respectively. The 5%WO<inf>3</inf>/NaX and 5%WO<inf>3</inf>/NaY provide lower activity due to coke formation over the acid sites. With high surface area and confined surface silanol of 5%WO<inf>3</inf>/MCM-41% and 5%WO<inf>3</inf>/SBA-15, in situ TR-EXAFS evidences the formation of only O[dbnd]W(O-Si)<inf>3</inf>. This species provides an isolated W=CH<inf>2</inf> site with relatively higher activity and is less prone to coke formation than the WO<inf>3</inf> cluster in 5%WO<inf>3</inf>/SiO<inf>2</inf>.
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Role of surface silanols and confinements of siliceous MFI supports on stability of active Ga species for ethane dehydrogenation
(2022-05-25)
Prakobtham, Kittipong
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Choojun, Kittisak
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Promchana, Pratya
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Sattayaporn, Suchinda
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Sooknoi, Tawan
Effect of surface silanol and confinement of siliceous MFI supports on the anchoring stability of active Ga species was demonstrated for ethane dehydrogenation. The catalysts were prepared by impregnation of Ga(NO<inf>3</inf>)<inf>3</inf> solution on siliceous MFI (Si/Al >500) and amorphous SiO<inf>2</inf>, and characterized by XRD, XRF, SEM-EDX, H<inf>2</inf>-TPR, NH<inf>3</inf>-TPD, in situ XANES, and EXAFS. Extra-framework Ga3+ species were present with different dispersions and reducibility, depending on the surface silanols. Proximity of the silanols within the surface confinement played an essential role on anchoring stability of the extra-framework Ga3+ species. All Ga catalysts provided > 93% ethylene selectivity with appreciable TOF ~60 h−1 for ethane dehydrogenation at 650°C. In situ XANES, EXAFS, and H<inf>2</inf>-TPR suggested that the highly dispersed extra-framework Ga3+ species could exist as dimeric Ga oxide [Ga<inf>2</inf>O<inf>2</inf>]2+ species. This active site could be reversibly interconverted with the less active [HGaOH]+ species under the H<inf>2</inf> flow.
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Ripening control of nam dok mai mango (Mangifera indica Linn.) with titanium dioxide
(2019-01-01)
Chaishome, Jedsada
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Tunsathitsak, Yossakorn
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Boonyaritthongchai, Panida
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Supapvanich, Suriyan
— This research aims to slow down the release of ethylene of ‘Nam Dok Mai’ mango during shipment transportation by using titanium dioxide as an absorbent. The result found that the mango begin to the ripening process after stored at 13°C for 12 days (ethylene and carbon dioxide around 0.06910 µL C2H4/kg.hr and 32.10 mg CO2/kg.hr, respectively). Then, the appropriate titanium dioxide was tested by trial at 3, 5 and 10 grams. The result showed that titanium dioxide decreased ethylene but each treatment were not statistically different (p <0.05). Afterward, all fruits were stored at 13°C for 14 days and at 25°C for 4 days, respectively. The physical and chemical properties of fruit were analyzed during storage time. After 14 days at 13°C, firmness, color, titratable acidity, pH, total soluble solids and ripening index of the treatments of titanium dioxide and control treatment were significant different. After 4 days at 25°C, the ripening process of fruit between titanium dioxide treatment and control treatment were not significant differences.
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Effect of ethylene treatments on limonin reduction in Thai pummelo (Citrus grandis (L.) Osbeck) fruit
(2011-11-01)
Pichaiyongvongdee, Suwanna
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Haruenkit, Ratiporn
Bitterness in the peel and juice of pummelo is mainly caused by limonin. This research studied different preparations of pummelo and used ethylene as fumigant at different concentrations in different treatments-namely, whole fruit (treatment1), pummelo fruit without the flavedo and albedo (treatment 2), pummelo fruit with only juice vesicle tissue (treatment 3) and pummelo juice (treatment 4). The limonin content in the flavedo, albedo, juice vesicle tissues and pummelo juice was significantly reduced following ethylene treatment. For effective limonin reduction in juice, the flavedo and albedo of pummelo fruit must be removed leaving only juice vesicle tissue (treatment 3) before treating with ethylene. The optimum treatment that reduced the limonin content by 78.38% was 200 ppm ethylene and 1.30 hr exposure. Treating pummelo with ethylene had no effect on nomilin, eriocitrin, neoeriocitrin and the antioxidant capacity of the juice; however, ethylene fumigation caused a slight decrease in the naringin content. Treating pummelo juice directly with ethylene had no effect on its limonin content.

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