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polypterus

Submitted by msgordon on Wed, 11/22/2017 - 18:49

First fossil record of Actinops was found in the Silurian period. Historically, Polypterus have been found in SA and Africa, however the 2 extant genera. of the family are only found in Africa. Species of Polyperterus have ganoine covered rhombic scales, and they respire through elastic recoil. Spiracles atop their head are used to inhale extra air - primitive lungs are used instead of a swim bladder.

ester synthesis

Submitted by msgordon on Wed, 11/22/2017 - 00:49

Acetic acid (0.74 mL, 13 mmol) and 3-methyl-1-butanol (1.2 mL, 11 mmol) was added to a round bottom flask containing several boiling chips. Sulfuric acid (4 drops) was added to the flask and the contents were mixed via expelling with a pipet. The mixture was refluxed for a total of 45 minutes using a reflux assembly with a side arm. Every fifteen minutes, the top layer consisting of organic product that was collected in the side arm was tilted back into the flask. After the last 15 minute block, the mixture was allowed to cool and the entire contents of the side arm was tilted back into the flask. Following this, the cooled mixture was transferred to a centrifuge tube containing water (1 mL) and the aqueous layer was extracted. The extraction of the aqueous layer was repeated twice following the addition of sodium bicarbonate (1 mL) and again with the addition of sodium chloride (1 mL). The product (1.09 g, 76.3%) was then dried with anhydrous calcium chloride and subsequently weighed before undergoing analysis by infrared spectroscopy.

 

Trimyristin discussion perfect paragraph

Submitted by msgordon on Mon, 11/20/2017 - 19:31

In this lab, trimyristin and myristic acid was synthesized from nutmeg in the presence of tert butyl methyl ether, sodium hydroxide, ethanol, and hydrochloric acid through reflux, recrystallization and hydrolysis. The melting points of the once recrystallized and twice recrystallized trimyristin were found to be 40℃-43℃ and 42℃-44℃ respectively. The melting point of myristic acid was found to be 46℃-48℃. These values are well below the literature values (56℃-57℃ for both trimyristin and myristic acid) and suggest that there were impurities present in the recrystallized trimyristin and the hydrolysis product. Thus, it is possible that the products were contaminated with solvent as contaminants would interfere with the lattice structure, leading to a lower melting point. The percent recovery of crude trimyristin was found to be 16.67%. This was to be expected as trimyristin is only a component of nutmeg and thus the possible yield is limited. The percent recovery for the once recrystallized trimyristin was 95.8% while the percent recovery for the twice recrystallized was  60.7%. The percent recovery of the second recrystallization could have been improved by using less acetone to prevent the dissolution of product while it cooled. Another portion of this mass loss can be attributed to the loss of product during suction filtration. As 3 moles of myristic acid is generated for every mole of trimyristin, the theoretical yield of the reaction was found to be 0.055 grams, however the mass of the product was 0.039 grams. As a result, the percent yield of myristic acid was found to be 70.9%. This mass loss can be attributed to losing product that was dissolved in the sodium hydroxide and ethanol mixture, as well as not using enough hydrochloric acid to precipitate myristic acid out of the solution.

Polyodon

Submitted by msgordon on Mon, 11/20/2017 - 19:28

Chondrostei is comprised of Polyodontidae and Acipenseridae. Psephurus is a member of the Polyodon family that is presumed to be extinct - the last known specimen was caught in 2007. Was found in the middle - lower part of the Yangtze and associated bodies of water. Brought to extinction b/c of the three gorges dam and illegal fishing. Polyodon occurs in the Mississippi River, Missouri River, Ohio River and associated systems. It is a ram feeder and filters zooplankton out of water column w/ gill rakers. The paddles found in Polyodontidae specimens serve as electrosensory organs used to detect changes in electric fields. Similar to ampullae of Lorenzini, used to detect plankton.

Amiids and Hiodons

Submitted by msgordon on Sat, 11/18/2017 - 20:36

Amiidae: sole living species: Amia calva. Found in slow waters with lots of vegetation. Generally found in eastern New England. Has vascularized swim bladder that allows it to breathe air (physostomous swim bladder). Males build nests in weedy areas —> clear weeds. Males then defend eggs and young. 

The Hiodons are the Mooneye fishes, found across North America. Have extremely large eyes, pectoral fins located at midline of body, whitish color. Hiodon tergius is found in NE.

Lungfishes

Submitted by msgordon on Fri, 11/17/2017 - 21:12

Lungfish have been found in SA, Africa, and Australia,. There are 3 families/genera and 6 species. Lunfish respire through buccal pumping, using a modified swim bladder as a lung. They have labyrinthine dentition. Reproduce by spawning, males guard eggs in Leptosiren - grow external gills to exhale O2 on eggs. Natural history: live in slow waters, swamps etc. Can aestivate, make slime cocoons. Larval Lepidosiren have external gills. Protopterus and Lepidosiren are obligate air breathers while Neoceratodus are facultative air breathers (optional)

Anguilla rostrata

Submitted by msgordon on Thu, 11/16/2017 - 23:18

Adult members of Anguilla rostrata  spawn in the Sargasso Sea, start out as eggs/pre-leptocephalus larva. They eventually transform into leptocephalus larva and migrate passively on theFlorida and Gulf Stream currents. Next stage is as a glass eel - unpigmented/early onset of pigmentation. Actively migrate on continental shelf and coastal rivers. Begin feeding. Next stage is an elver - 7-8 cm in length, fully pigmented, actively migrate upriver in deep waters. Yellow eel, > 30cm total length, active feeding and growth, intermittent migration bc of weather/water conditions, territorial and nocturnal. Last stage is silver eel, begins down river spawning migration, nocturnal, stops feeding at start of emigration to Sargasso Sea. Glass eels are highly sought after in sushi

trimyristin discussion

Submitted by msgordon on Thu, 11/16/2017 - 00:01

In this lab, trimyristin and myristic acid was synthesized from nutmeg in the presence of tert butyl methyl ether, sodium hydroxide, ethanol, and hydrochloric acid through reflux, recrystallization and hydrolysis. The melting points of the once recrystallized and twice recrystallized trimyristin were found to be 40℃-43℃ and 42℃-44℃ respectively. The melting point of myristic acid was found to be 46℃-48℃. These values are well below the literature values (56℃-57℃ for both trimyristin and myristic acid) and suggest that there were impurities present in the recrystallized trimyristin and the hydrolysis product. Thus, it is possible that the products were contaminated with solvent as contaminants would interfere with the lattice structure, leading to a lower melting point. The percent recovery of crude trimyristin was found to be 16.67%. This was to be expected as trimyristin is only a component of nutmeg and thus the possible yield is limited. The percent recovery for the once recrystallized trimyristin was 95.8% while the percent recovery for the twice recrystallized was  60.7%. The percent recovery of the second recrystallization could have been improved by using less acetone to prevent the dissolution of product while it cooled. Another portion of this mass loss can be attributed to the loss of product during suction filtration. As 3 moles of myristic acid is generated for every mole of trimyristin, the theoretical yield of the reaction was found to be 0.055 grams, however the mass of the product was 0.039 grams. Thus, the percent yield of myristic acid was found to be 70.9%. This mass loss can be attributed to losing product that was dissolved in the sodium hydroxide and ethanol mixture, as well as not using enough hydrochloric acid to precipitate myristic acid out of the solution.

 

Trimyristin procedure

Submitted by msgordon on Sun, 11/12/2017 - 23:03

Ground nutmeg (1.002 g) and tert-butyl methyl ether (3 mL, x mmol) was added to a round bottom flask along with several boiling chips. The mixture was condensed for 10 minutes using a distillation column and then the solids were allowed to settle. The resulting liquid was separated from the solid via a micro scale filtration assembly. The solvent was evaporated in the fume hood until a gummy yellow solid remained. The crude trimyristin was recrystallized in the presence of acetone and collected via suction filtration. A small portion of the once recrystallized trimyristin (95.8%) was set aside. The melting point of the recrystallized trimyristin was found to be 40℃-43℃ (56℃-57℃). The remaining product (0.058 g, x mmol) was transferred to a round bottom flask with 6M NaOH (2 mL), and 95% ethanol solution (2 mL). The mixture was refluxed for 45 minutes. At the same time, the once recrystallized trimyristin (0.102 g, x mmol) was recrystallized and subsequently collected via suction filtration. The melting point of the twice recrystallized trimyristin (60.7%) was determined to be 40℃-42℃ (56℃-57℃). Once the hydrolysis of the mixture was finished, the product was transferred into a beaker along with water (8 mL) before hydrochloric acid (2 mL) was added. Myristic acid (x g, x mmol) precipitated as a grainy yellow-brown substance and subsequently collected via suction filtration. The melting point of myristic acid was found to be ___.

 

Ether Synthesis

Submitted by msgordon on Sun, 11/12/2017 - 12:58

In this lab, butyl naphthyl ether was synthesized from 2-naphthol in the presence of sodium hydroxide, ethanol, and a butyl iodide using a Williamson Ether Synthesis reaction. The melting point of the resulting product was determined to be a range of 30℃-32℃, which is slightly below the literature value range (33℃-35℃). The relative proximity between the experimental melting point and the literature melting point range suggests that the product is fairly pure. Since there is a 1:1 ratio between the moles of 2-naphthol and butyl naphthyl ether, the theoretical yield of the reaction is 0.278 g, however the mass of the product was found to be 0.05 g, giving a percent yield of 18%. The low yield can be attributed to the loss of product through filtration. In future experiments, this mass loss could be avoided by using a different compound to cool the product without causing an overflow of liquid in the funnel during filtration that occurred when ice was used. Thin layer chromatography was used to further assess the purity and polarity of the product. The first solvent used consisted of a 95:5 mixture of hexanes:ethyl acetate. However this resulted in an uneven separation, presumably because of the high amount of the nonpolar hexanes compared to the polar ethyl acetate. On the other hand, a TLC test using a 95:5 mixture of ethyl acetate:hexanes resulted in an excessive amount of separation due to the high polarity of the solvent. Thus, it was a mixture of 90:10 hexanes:ethyl acetate mixture that provided the best separation. The presence of only one spot in the product column of the TLC plate indicated that the product is pure and consisted of only one component. However, this does not entirely confirm the purity of the product, as a single spot could be comprised of both the desired product and a second component of similar polarity. The product spot experienced a considerable amount of separation(Rf = 0.85) which was expected as butyl naphthyl ether is a relatively nonpolar compound and should show separation. 2-naphthol is a polar compound however, and thus should not experience much separation which was evident in the starting material spot and the co-spot (Rf = 0.17). As such, the results of the TLC analysis suggested that the product was indeed butyl naphthyl ether.

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