This data can also further be analyzed through melting our isolated crystals and comparing the obtained melting point range against the theoretical melting point of 4,6-O-benzylidene--D-glucopyranoside to determine the relative purity of our final product. 4,6-O-benzylidene--D-glucopyranoside has a theoretical melting point of 166°C. Thus, when comparing our obtained melting point range of 166-168°C, we can infer that our obtained yield was quite pure.With respect to part B of this experiment, the purpose of this part was to determine the presence and relative concentration of reducing sugars in 4 different solutions, being a sucrose, glucose, milk and coke solution respectively. This was achieved using Benedict’s test, which identifies reducing sugars based on their free ketone and aldehyde functional groups. As a result, the glucose and coke solutions were found to contain reducing sugars with the glucose solution being determined to contain a higher concentration of such. Conversely, the sucrose and milk solutions were determined not to contain any reducing sugars. To achieve this result, a few key steps had to be followed. Each solution was initially placed into its own test tube and labelled, where Sucrose and Glucose solutions were made by dissolving each sample in water.Benedict’s solution was then added into each test tube, which were then heated in a steam bath. As Benedict’s solution and simple carbohydrates and heated, the solution undergoes a color change to orange red/brick red. This reaction is caused by the fact that reducing sugars are capable of transferring hydrogens to other compounds in a process called reduction. As these sugars are mixed with Benedict’s reagent and heated, a reduction causes the reagent to change color as its copper (II) ions are reduced to copper (I) ions (SEP., 2013). As the concentration of reducing sugar increases, the nearer the final color is to “brick” red. Due to the nature of its structure, glucose, a monosaccharide, exists in an aldohexose from, also known as D-glucose. This given structure contains an aldehyde group at one end. As aresult, a reduction reaction takes place when this form is exposed to Benedict’s reagent and heated, as seen in this experiment.
Subscribe to view the full document.
In comparison, sucrose is a disaccharide formed of glucose and fructose monomers. Their connection however doesn’t allow for a free aldehyde group on one end, as seen with glucose. As a result, there is no reducing property associated with sucrose, which was indicative of its color remaining constant during the experiment. As it pertained to the milk solution, no significant color change took place although the solution’s shade of blue did become darker. Milk contains disaccharide lactose, which is composed of -glucose and -galactose monomers. The latter, in turn, does have a possible conformation in which a free aldehyde group is present, and thus theoretically could have contributed to a color change.
As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.
Temple University Fox School of Business ‘17, Course Hero Intern
I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.
University of Pennsylvania ‘17, Course Hero Intern
The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.