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Synthesis of Cyclohexene via Dehydration of Cyclohexanol Discussion Part 2

Submitted by malberigi on Fri, 03/23/2018 - 10:53

Cyclohexene was confirmed in the product via two chemical tests using bromine in dichloromethane and potassium permanganate.  In the bromine test, the reddish-orange bromine would change to colorless in the presence of an alkene, which was the result observed.  When the potassium permanganate was added it changed from purple to colorless with a dark brown precipitate of manganese dioxide, which indicated the presence of an alkene.  These tests were also performed on an alkene.  The bromine test resulted in a reddish-orange color because bromine does not react with alkanes.  The potassium permanganate test resulted in a purple color because there was no interaction with the alkane.  The infrared spectroscopy (IR) analysis showed two distinct peaks.  One peak at 3022.45 cm-1 corresponds to sp2-hybridized carbons within the cyclohexane.  The second peak at 2912.51 cm-1 corresponds to sp3-hybridized carbons within the cyclohexene.  According to the gas chromatography (GC) analysis there is only one lower point material at a retention time of 0.435 that contains 100% of the area indicating the product of cyclohexene is pure.  The amount of cyclohexanol still present in the product is insignificant since it did not appear in the GC analysis. Using a high-boiling component, such as toluene, to continue the distillation and eliminating more water from the product would result in higher present yield and more purity with the obtained product.

Synthesis of Cyclohexene via Dehydration of Cyclohexanol Discussion Part 1

Submitted by malberigi on Thu, 03/22/2018 - 16:59

The target product of cyclohexene was obtained through a dehydration reaction of cyclohexanol using 80% phosphoric acid as a catalyst and resulted in a 47% yield.  A fractional distillation column was used to separate the cyclohexene product from the remaining phosphoric acid and impurities.  The cyclohexene was purified at a boiling point (64 °C), which is far lower than the documented boiling point of cyclohexanol starting material.  The presence of cyclohexene was confirmed from the characterization analyses preformed.

Cyclohexanol dehydrates to yield cyclohexene in a one to one ratio.  Cyclohexanol (1.99 g) was used as a starting material and therefore should have yielded cyclohexene (1.64 g).  The actual yield of cyclohexene was 0.77 g, which gives a percent yield of 47%.  The low yield is most likely due to low-boiling components of cyclohexene and water that leave some product behind in the flask and in the column.  Using a high-boiling component, such as toluene, to continue the distillation, would most likely have helped recover product.  However, by eliminating this step, it greatly reduced the time spent on the experiment.


Synthesis of Cyclohexene via Dehydration of Cyclohexanol Procedure

Submitted by malberigi on Wed, 03/21/2018 - 15:02

Cyclohexanol (1.99 g, 19.8 mmol) was measured into a 5mL round-bottomed (rb) flask.  85% phosphoric acid (0.5 mL) was added to the rb flask.  The system was heated and the product was collected through fractional distillation.  The temperature plateau occurred at 64 °C and the product was obtained in a collection vial.  The product was transferred to a reaction tube.  The reaction tube was washed with water (1 mL).  The procedure was repeated with sodium hydroxide (1 mL) followed by saturated sodium chloride (1 mL).  The product was then dried with calcium chloride pellets (5 min).  The remaining product yielded (0.77 g, 47%).  The product was tested for the compounds it contained with infrared spectroscopy and gas chromatography (one peak) with a retention time (RT) of 0.435.  A bromine solution was added drop-wise to (0.5 mL) of the product and the prescence of cyclohexene was indicated by a color change of the bromine from reddish-orange to colorless.  A potassium permanganate reagent was added drop-wise to (0.3 mL) of the product and the presence of cyclohexene was indicated by a color change from purple to clear with a dark brown precipitate.  These tests were then compared to cyclohexane, which did not react with the reagents.

Seed and feeder color preference in native New England bird species

Submitted by malberigi on Tue, 03/20/2018 - 22:22

Our research question involves seed color and feeder color discrimination in native New England bird species. We would like to test whether the color of the seed influences the rate at which it is consumed.  The same variety of seed would be used and colored via food dye, the different colors would then be placed in the same color feeder. These colors would include unnatural colors such as blue, pink, and purple and natural colors such as green, black, and red.  We would also include a control with no addition of color. We would also like to investigate as to whether the color of the feeder influences the frequency of visits. The same seed would be used in different color feeders and feeders would be observed for a set amount of time.  The feeder colors could be the same list of colors included previously and in place of the control would be clear/silver.  The preferences observed with both experiments in a natural environment can then be compared to that of an urban setting. This comparison may pose a developmental question as to how behavior is dictated by development of an individual in different environments.

Salt Marsh

Submitted by malberigi on Mon, 03/19/2018 - 20:45

            The salt marsh is located in a protected, low energy zone just outside the highest beachfront dunes.  It is a depository zone, comprised of thick layers of mud and sand.  Salt marshes are a critical interface between the land and sea.  They provide habitat for fish, birds, and shellfish; protect coastal cities from storms; and they take nutrients out of the water coming from upland areas, which protects coastal bays from over-pollution.  At higher elevations in the upper marsh zone, there is much less tidal inflow, resulting in lower salinity levels.  Soil salinity in thelower marsh zone is fairly constant due to everyday annual tidal flow. Rainfall can reduce salinity and evapotranspiration can increase salinity during dry periods.  As a result, there are microhabitats populated by different species of flora and fauna dependent on their physiological abilities. The flora of a salt marsh is differentiated into levels according to the plants' individual tolerance of salinity and water table levels


Submitted by malberigi on Sun, 03/18/2018 - 19:55

Mudflats, or also known as tidal flats, are coastal wetlands that form when mud is deposited by tides or rivers. They are found in sheltered areas such as bays, lagoons, and estuaries. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of estuarine silts, clays and marine animal detritus. Most of the sediment within a mudflat is within the intertidal zone, and thus the flat is submerged and exposed approximately twice daily.  Mudflats dissipate wave energy very effectively and therefore are an excellent tidal defense against eroding saltmarsh, damaging coastal defenses and flooding low-lying land. Mudflats may also be important for pollution sequestration, as the organic material draws in pollutants and they may therefore contain large concentrations of heavy metals. Mudflats have high biological productivity but low diversity.

R and K selection

Submitted by malberigi on Tue, 03/13/2018 - 10:31

R-selected species are those that place an emphasis on a high growth rate, and, typically exploit less-crowded ecological niches.  They produce many offspring, each of which has a relatively low probability of surviving to adulthood.  In unstable or unpredictable environments, R-selection predominates as the ability to reproduce quickly is crucial.  Among the traits that are thought to characterize R-selection are small body size, early maturity onset, short generation time, and the ability to disperse offspring widely.  R-selected species produce thousands of offspring but provide little to no parental care after birth.  By contrast, K-selected species display traits associated with living at densities close to carrying capacity.  Typically they are strong competitors in crowded niches that invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood.  Populations of K-selected organisms are very constant in number and close to the maximum that the environment can bear, unlike r-selected populations, where population size changes more rapidly.  Traits that are thought to be characteristic of K-selection include large body size, long life expectancy, and the production of fewer offspring, which often require extensive parental care until they mature. 

What do I Remember from Statistics

Submitted by malberigi on Wed, 03/07/2018 - 21:54

This past fall semester I was enrolled in Statistics 240 which was my second college statistics class and my first at Umass Amherst.  We began the semester talking about histograms, box plots, and stem and leaf plots which are all methods of organizing data.  Using these methods to manipulate data allows for clear relationship inferences when dealing with large amounts of data.  We also utilized chi squared tests to understand the relationships between numbers in a data set via observed and expected values.  Later on in the semester we studied binomial distribution, normal distributions, probability distributions, and used the Central Limit theorem when certain criteria were not met.  The course finished with a group project where we chose two variables to compare using Minitab as a statistical platform.  The project allowed for creativity when constructing how the data would be presented and what analytical tests would be performed on the data.  This statistics class at Umass built upon the previous knowledge I had from my statistics class taken during my associate's degree.  I have found that the methods of data analysis have been prevalent in many upper level biology classes I have taken.  I have seen countless examples of data manipulation in primary scientific literature and understanding when these methods are performed allows for a deeper comprehension of the literature.  

Evolutionary Significance of Olfactory Lateralization

Submitted by malberigi on Wed, 03/07/2018 - 15:45

We learned in class about how scout honeybees search for food and confer information regarding direction and distance to the rest of the colony.  Olfactory lateralization might allow for worker bees to better imitate the directions of the scout bees because certain olfactory cues to where the food can be found are more easily imitated when all bees have the same levels of lateralized olfaction.  Bees are social animals and in order to pass off information from one individual to another, similar lateralization of senses and brain function must play a role in understanding that information.

Operant Conditioning (Lateralization Article)

Submitted by malberigi on Tue, 03/06/2018 - 21:49

In class we have learned about four different types of operant conditioning.  Operant conditioning works to modify voluntary behavior as a result of consequences and two types were used to train the bees in this experiment.  The first is positive reinforcement, which was used to train the bees to associate extending their proboscis in expectation of a reward.  The researchers conditioned the bees to extend their proboscis only when they smelled sugar water or sugar water mixed with a scent to train them in recognizing the correct scent.  The other type of operant conditioning used in this experiment was punishment, which was used to train bees to associate extending their proboscis to salt water or salt water mixed with a scent with a negative experience.  The bees that extended their proboscis towards salt water would receive a drop of saltwater in the mouth, which was a negative experience.  These two types of conditioning allowed the scientists to train bees to extend their proboscis to sugar water and not to salt water.


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