Tag Archives: research

Quote

Penelitian dengan Perabot Rumah Tangga

Yang pernah berkunjung ke lab saya pasti tahu kalau peralatan di lab saya sudah layak untuk dimusiumkan. Sebagian besar sudah udzur dan tidak berfungsi lagi. Padahal penelitian tetap harus jalan terus. Penelitian tahun ini besar tanggung jawabnya dan kalau gagal nasip saya bisa sama seperti Pak Dasep. Agar penelitian tetap bisa berjalan saya terpaksa menggunakan perabotan rumah tangga, sebagian pinjam ke perabotan istri di rumah. Mau bagaimana lagi.

image

Peralatan laboratorium umumnya mahal-mahal dan kapasitasnya kecil. Memang sih presisi dan kualitasnya bagus. Anggaran penelitian tidak boleh untuk membeli alat. Teman-teman di lab, khususnya lab saya, jadi frustasi. Mau nimbang saja mesti numpang di lab tetangga. Autoclave rusak, numpang lagi ke lab lain. Sedih.

Continue reading

Advertisements

Preparation of the cellulose nitrate

This methods is part of the book:
Klemm, D., et al. “Comprehensive cellulose chemistry: v. 2: functionalization of cellulose: functionalization of cellulose.” (1998).

A sample of about 0.8 g cellulose is mixed with 40 ml of the nitration acid, and coole down to 0oC. This mixture is shaken vigorously and then kept for 3 h at 0oC with occasional shaking. Subsequently most of the nitration acid is separated from the cellulose on a coarse sintered-glass crucible by pressing with glass stopper. After putting the filter crucible onto a suction flask, the sample is neutralized stepwise by addition of a total volume of 240 ml of 2% by weight aqueous Na2CO3 solution, which is filtered through the crucible without suction. Subsequently the sample is washed with about 8 l of distilled water, again applying no suction. After these washing, most of the water covering the sample is drawn off by suction, and the cellulose nitrate is stabilized for 2 h at room temperature by covering it with methanol in a beaker. After separating the methanol by filtration, the sample is dried in vacuo over P2O5 at 20oC for at least 15h.

Determination of the carboxyl group content of cellulose samples by methylene blue sorption

This methods is part of the book:
Klemm, D., et al. “Comprehensive cellulose chemistry: v. 2: functionalization of cellulose: functionalization of cellulose.” (1998).

A weighed cellulose samples of known water content up to 0.5 g is suspended in 25 ml of aquaeus methylne blue chloride solution (300mg/l) and 25 ml of borate buffer of pH = 8.5 for 1 h at 20 oC in a 100 Erlenmeyer flask and then filtered through a sintered-glass disk. 5 or 10 ml of the filtrate are transferred to a 100 ml calibrated flask. Then 100 of 0.1 N HCl and subsequently water, up to 100 ml, are added. Then the methylene blue content of the liquid is determined photometrically, employing a calibration plot, and from the result the total amount of free, i.e. nonsorbed, methylene blue is calculated. The carboxyl group content of the sample is obtained according to:

rumus_carbonyl - 1

Reference:
Phillip, B., Rehder, W., Lang H. Papier 1965, 1-10

Determination of the carbonyl group content of cellulose samples by oximation

This methods is part of the book:
Klemm, D., et al. “Comprehensive cellulose chemistry: v. 2: functionalization of cellulose: functionalization of cellulose.” (1998).

2 g of an air dry sample of known moisture content is suspeded in 100ml 0f 0.02 N aquaeous zinc acetate solution in a 300 ml Erlenmeyer flask under vigorous stirring. After a residence of 2-6 h at room temperature in the covered flask the liquid is sucked off and the moist sample is immediately and quantitatively returned to the flask and subsequently suspended in 100 ml of the oximation reagen (35 g hydroxilamine hydrochoride, 55 g zink acetate, 160 ml 1 N NaOH and 1.6 ml glacial acetic acid/l aquaeous solution) appliying a gentle shaking. After a residence time of 20 h at 20oC, the liquid is again sucked off through the same sintered-glass disk and twice washed with water. Subsequently the sample is suspended again in the same flask in 100 of 0.02 N zinc acetate solution. After 2 h the liquid is again sucked off and the sample is washed with aqueous zinc acetate solution of the same concentration. The moist oximated sample is then immadiately subjected to a determination of the nitrogen content by Kjeldahl method, employing finally a calorimetric determination of the NH4+ formed with Nesslers reagent. I umol of nitrogen correspond to 1 umol of carbonyl groups in the sample.

Reference:
Laboratory procedure of Fraunhofer Institute of Applied Polymer Research.

Determination of the acetyl group DS of cellulose acetate

This methods is part of the book:
Klemm, D., et al. “Comprehensive cellulose chemistry: v. 2: functionalization of cellulose: functionalization of cellulose.” (1998).

0.5 g of dry cellulose acetate is swollen in 25 ml of an acetone/water mixture (1:1 by volume) for 24 h at room temperature. Then 12.5 ml of 1 N KOH in ethanol are added, and a complete deacetylation is formed by keeping this mixture for 24 h at room temperature. The excess of alkali is titrated with N/2 aqueous HCl using phenolpthalein as indicator, and an excess of 2 ml of N/2 HCl is added, which is back-titrated after 24 h with N/2 NaOH. From the titration result, the total amount of alkali consumed for saponification of the acetyl groups/g of sample is obtained. Calculation of ‘% of bound acetic acid’ and DSAcetyl is performed accoding to

rumus_acetyl - 1

Reference:
Procedure of the Fraunhofer Institute of Applied Polymer Research, Teltow-Seehof.

State of the art of cellulosic ethanol

Ethanol or ethyl alcohol (CH3CH2OH) is an important organic chemical because of its unique properties, and therefore can be used widely for various purposes. Under ordinary conditions, ethanol is a volatile, flammable, clear, colorless liquid, miscible in both water and non-polar solvents. Ethanol and ethanol-gasoline blends have a long history as automotive fuels. In the late 1800 for example, Henry Ford, Nicholas Otto and others built engines and cars that could run on ethanol (Solomon, Barnes, & Halvorsen, 2007).
Continue reading