Carlo V. Caballero BS ChE-4
March 11, 2011 Rating: Experiment No. 5 Solid-Liquid Extraction
I. Objectives • To be able to extract coconut oil from coconut meat using organic solvents for non-food applications. • To compare the capability of hexane, chloroform, and carbon tetrachloride to extract coconut oil from coconut meat. • To compare one-stage and two-stage extraction of coconut oil from coconut meat using chloroform. II. Theory Vegetable oils, sugar, instant coffee, medicines from medicinal plants, etc. are made by processing solid starting material using extraction with liquid solvent(s). Solid-liquid extraction or leaching generally refers to the removal of a component from a solid using a solvent liquid. Leaching is one of many solid-fluid separation processes that are carried out in the chemical, mineral and related industries. In fact, it is one of the oldest unit operations in the chemical industries. The fundamental principle behind leaching is the removal of a soluble material from an insoluble, permeable solid phase. The soluble fraction, solid or liquid, may exist mechanically in the pore structure of the insoluble material or chemically combined with that material. This soluble material is removed through dissolution in a dissolving solvent. The most familiar example of leaching is the extraction of tea and coffee, and most importantly mineral recovery. The rate of leaching (extraction) is affected by many physical and chemical phenomena. Mass transfer and equilibrium phenomena obviously play major roles. The process of leaching consists of the following steps: the solvent diffuses into the solid phase; the diffused solvent dissolves the solutes (i.e. transfer the solute to the liquid phase). Leaching is always followed by solvent recovery, which involves another mass transfer operation; such as filtration. Coconut meat is the flesh of the coconut fruit, a tropical fruit produced by the coconut tree. There are a number of uses uses for coconut meat, along with other other parts of the coconut. There are two types of coconut meat. Young or “green” coconuts have very soft meat which is almost gelatinous in texture, soft enough to easily scoop out of the fruit with a spoon. This type is sometimes called coconut jelly, and it is classically served as a snack. Mature coconuts have firmer white meat which tends to cling more stubbornly to the inside of the shell, making it more challenging to remove.s
Hexane is a hydrocarbon with the chemical formula C 6H14; that is, an alkane with six carbon atoms. Hexanes are used in the formulation of glues for shoes, leather products, and roofing. They are also used to extract cooking oils from seeds, for cleansing and degreasing all sorts of items, and in textile manufacturing. Chloroform is the organic compound with formula CHCl 3. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous. It is a common solvent in the laboratory because it is relatively unreactive, miscible with most organic liquids, and conveniently volatile. Carbon tetrachloride is the organic compound with the formula CCl 4. It is used as a solvent in synthetic chemistry research, but because of its adverse health effects, it is no longer commonly used, and chemists generally try to replace it with other solvents.
III. Materials and Equipment A. Materials Grated Coconut Meat Carbon Tetrachloride (CCl4) Chloroform (CHCl3) Hexane (C6H14) B. Equipment Analytical Balance Beaker Clean Cloth Graduated Cylinder Hot Plate Spatula Stirring Rod Strainer IV. Procedure We first weighed three (3) 80 grams, approximately, of grated coconut meat using the analytical balance. We then recorded the exact weights of the meat used. In the amount of 200 ml each, hexane (C6H14), chloroform (CHCl3), and carbon tetrachloride (CCl 4) were also prepared. Next, we mixed the coconut meats with the different solvents. For about 5 minutes, the mixtures were stirred and a short settling time was allowed. By straining and expression, we have separated the meat from the solvent containing dissolved coconut oil.
We have observed that the remaining meat still contains absorbed solvents. So, we have dried the meats over the hot plate for about 30 min to evaporate the absorbed solvents. The dried meats were then allowed to cool to ambient temperature. We have taken the weights of the dried meats. The amount of oil extracted by the solvents was equal to the difference in the initial and final weights of the coconut. Another 80 g of meat was prepared and extracted with 200 ml of chloroform for two-stage extraction process. The meat was then separated from the solvent. We have used another 200 ml of chloroform to extract the coconut oil. The meat was again separated from the solvent and then dried for about 30 minutes. We have taken the weight of the dried meat, and the total amount of oil extracted by the solvent was equal to the difference between the initial and final weights of the meat.
V. Diagram A D
E
B
F
C
Legend: A - Graduated cylinder B - Stirring rod C - Beaker D - Grated coconut meat E - Hot plate F - Strainer
VI. Data and Results Solvent
Initial Weight (g)
Final Weight (g)
Difference (g)
Percent Extracted (%)
Hexane
80.9861
48.9513
32.0348
39.556
Chloroform
80.4702
45.1487
35.3215
43.894
Carbon Tetrachloride
80.1486
47.5591
32.5895
40.661
Single stage extraction of coconut oil from coconut meat using 200 ml of solvent.
Number of Stages One Stage Two Stages
Initial Weight (g)
Final Weight (g)
Difference (g)
Percent Extracted (%)
80.4702
45.1487
35.3215
43.894
80
42.2745
37.7255
47.157
One- and two-stage extraction of coconut oil from coconut meat using 200 ml of chloroform as solvent.
VII. Observation and Discussion of Results From the experiment we have performed, I have observed that when hexane was mixed with the grated coconut meat, it mixed properly and uniform distribution was noticed. And when chloroform and carbon tetrachloride were mixed with coconut meat each in a separate beaker, we have observed that the grated coconut meat was suspended above the solvents, respectively. Among the three solvents used, chloroform had the highest percentage of oil extracted from the coconut meat. The difference in percentage of the oil extracted between the three is not so big. We have also performed two-stage extraction process using chloroform. And it showed that higher percentage of oil was extracted from the grated coconut meat. Almost 50% is extracted compared to that of the 43% using one-stage extraction.
VIII. Conclusion From the experiment we have done, we were able to extract coconut oil from coconut meat using organic solvents for non-food applications. We have done this through solid-liquid extraction process. Solid liquid extraction is the process of extracting the solids by dissolving the substances containing the required solid into liquids. This extraction process allows soluble components to be removed from solids using a solvent.
We have used 3 solvents (hexane, chloroform and carbon tetrachloride) to extract the oil from the grated coconut meat and based on the results we have obtained, chloroform had the highest capability to extract the oil.
IX. Applications Applications of this unit operation include obtaining oil from oil seeds or leaching of metal salts from ores. The largest use of solid/liquid extraction is in the extractive metallurgical, vegetable oil, and sugar industries.
X. References http://www.gunt.de/download/extraction_english.pdf http://wiki.answers.com/Q/What_is_solid-liquid_extraction#ixzz1GaF09FfS http://www.scribd.com/doc/29921061/Solid-Liquid-Extraction-Leaching http://www.tutorvista.com/science/disadvantages-of-solid-liquid-extraction
