Judul: Optimasi Waktu Reaksi, Suhu Reaksi dan Konsentrasi Katalis pada Sintesis Gliserol Tert-Butyl Eter (GTBE).
Abstrak: Biodiesel is one of the fuels that many countries develop because it’s renewable and eco-friendly. Biodiesel is used to substitute petroleum fuel especially diesel fuel. However, biodiesel still have disadvantages, that is the biodiesel’s cloud point and pour point is higher than petroleum based diesel fuel. This disadvantage becomes a problem on biodiesel utilization especially in subtropical countries. This problem can be solved by addition of chemicals to prevent agglomeration of crystals that are formed in biodiesel in low temperature. Increasing production of biodiesel cause increasing biodiesel by products as well, one of the biodiesel by products is glycerol. Glycerol has characteristic as anti -freezing (cryoprotectant) but it can’t be added directly to fuel because of polarity difference, decomposition, and polymerization can rise consequential engine problems at high temparatures. Glycerol must be modified to derivatives that are compatible with diesel and biodiesel prior to be added to the fuel. The most obvious derivative of glycerol has an analogy in gasoline reformulation (oxygenated gasoline). Etherification of glycerol with isobutylene produce branched ether that can be mixed with biodiesel to make a fuel with lower viscosity and cloud point value below 0°C. Beside of using isobutylene, etherification of glycerol also can be done with tert -butyl alcohol (TBA). The commonly used catalyst in etherification of glycerol is commercial strong acid ion-exchange catalyst, such as Amberlist. In this research, the possibility to replace expensive Amberlist with local bentonite was evaluated. Natural bentonite was activated by hydrochloric acid (HCl) prior to use as catalyst. The effect and optimization of reaction time, temperature and concentration of catalyst to the concentration of produced GTBE was studied. Experimental design that used is central composite design, it is one kind of the Response Surface Methodology (RSM). Lower level for reaction time is 6 hours, temperature is 60C, and concentration of catalyst is 2.5%. Higher level for reaction time is 10 hours, temperature is 80C, and concentration of catalyst is 7.5%. The result showed that reaction time doesn’t have signification influence to concentration of GTBE in confidence interval 95 %. Whereas , temperature and concentration of catalyst have signification influence s to concentration of GTBE in confidence interval 95 %. The result from analysis with software Design Expert 7.1.6 (free trial) shows that the relationship between reaction time (X 1), temperature (X2), and concentration of catalyst (X3) generate saddle point model. From optimization t est, the sqrt GTBE’s value is predicted 613.10 with reaction time is 4.9 hours, temperature is 66.2C and concentration of catalyst is 9 .7 %. Verification of that prediction of optimum condition resulted in sqrt GTBE’s value of 980. 86. This result showed that the model couldn’t predict the optimum condition of GTBE reaction, since the optimum point was out of the range. Optimum concentration of GTBE was predicted when reaction time below 6 hours, temperature above 60°C, and concentration of catalyst above 7 .5 %. The GTBE effectiveness test to reduce biodiesel’s cloud point and pour point was done by mixing GTBE in biodiesel with volume ratio 1:10. The result from this test showed that biodiesel
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Judul: Pemucatan Gliserol Kasar Hasil Samping Pembuatan Biodiesel Menggunakan Adsorben
Abstrak: Glycerol compound is a byproduct the making of biodiesel that high economic value. Glycerol with various levels of quality are needed as raw materials in industry. Glycerol used in the food industry, cosmetics industry, pharmaceutical industry, tobacco processing industry, industrial lubricating, and also oleochemical industry. In the future when the demand of biodiesel is increasing along with population growth, it also increases the production of glycerol. The use of glycerol especially pure glycerol in a various of products have been developed. But before the process of making a compound glycerol derivatives of glycerol refining process takes most of which crude glycerol was mixed with other materials. The purpose of this research is to determine the effect of adsorbent concentration on the purification of glycerol in order to determine the type and combination of effective adsorbent to produce pure glycerol. The treatment tested in this study is the type of adsorbent (activated carbon and bentonite) and a combination of both adsorbent added. The ratio of activated carbon and bentonite added is 4: 4 (adsorbent total is 8 %), 4: 6 (adsorbent total is 10%), 4: 8 (adsorbent total is 12%) and 4: 10 (adsorbent total is 14%) of the weight of crude glycerol. The results showed that the concentration of adsorbent used in the bleaching have significant effect on water content, ash content and color of glycerol produced but did not have real impact on the number of acid. The use of adsorbent with a total of 14 % to produce glycerol with water content and ash content lower than most others. Based on absorbance values, the adsorbent total 14 % are also more effective in absorbing the colors then the color of the resulting glycerol is clearer. The influence of the total of adsorbent to the water content is higher the amount of adsorbent is added, then the value of water content lower glycerol. Neither the value of ash content nor the lower absorbance with increasing number of adsorbent used. The ratio of the use of adsorbent (activated carbon: bentonite) is the best ratio of 4:10 with the lowest water content value (0.663%), the lowest ash content (0.0543%), transmitance (low absorbance value of 1.987) and 8.74 glycerol levels %. Glycerol analysis using GC-MS (Gass Chromatography Mass Spectrometry) showed that glycerol before and after the purification process still contains the methyl esters of glycerol so that low purity. This is because the reaction is not perfect at the time of the process of making biodiesel. But after the purification process of glycerol content increased from 0.85% to 8.74%.
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Judul: Keanekaragaman spesies kadal kelas reptilia, infraordo cincomorpha di kelompok hutan gunung salak
Abstrak: Infraordo Scincomorpha merupakan anggota ordo Squamata yang paling melimpah dan bersifat kosmopolitan, dengan kecenderungan yang mengarah kepada mereduksinya lengan. Anggota dari infraordo ini yang terdapat di Indonesia yaitu famili Scincidae, Dibamidae dan Lacertidae. Penelitian ini bertujuan untuk mengetahui keragaman dan distribusi habitat dari anggota infraordo Scincomorpha di Kelompok Hutan Gunung Salak Taman Nasional Gunung Halimun-Salak. Metode pengambilan data dilakukan dengan cara mencari sampel sepanjang jalur pendakian menggunakan metode simple random sampling. Beberapa sampel yang mewakili berusaha ditangkap dan identifikasi menggunakan kunci identifikasi Boulenger (1912), Rooij (1915), Iskandar (1996) dan Kurniati (2003). Dari 97 ekor kadal yang ditemukan bisa dikelompokkan ke dalam 2 famili. Anggota famili pertama yaitu Scincidae diwakili oleh Mabuia multifasciata, Sphenomorphus puncticentralis dan Sphenomorphus sanctus, famili kedua adalah Lacertidae yang diwakili oleh Tachydromus sexlineatus. Semua hewan yang ditemukan mempunyai habitat utama berupa daerah-daerah yang cukup terbuka.
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