Bioinorganic Coordination Chemistry
This experiment uses H2TTP made during the last lab and hydrated
copper (II) acetate to convert the H2TTP to Cu(TTP). The reaction
proceeds by being refluxed for 30 minutes. The final product is a
non-iridescent purple color, unlike the vivid, shimmering purple color
of the starting H2TTP.
Introduction
Thin layer chromatography, or TLC, is used as a prerequisite for
column chromatography. When performing types of chromatography, like
TLC, the polarity of solvents is extremely important. This lab uses
TLC plates, five solvents (hexane, toluene, ethyl acetate,
dichloromethane, and acetone), and small evaporating dishes to
determine which solvent would be best to use in column chromatography.
The least polar solvent is hexane, which has a polarity index of 0.1.
Toluene has a polarity index of 2.4, while ethyl acetate’s is almost
twice that at 4.4. By comparing the polarity indexes, you can tell
what solvent will separate your dots of product on your TLC plates the
best (Skoog 761).
Experimental Section
The equipment needed for this experiment is as following: 100 mL round
bottom flask, stir bar, water condenser, hot plate, UV light, Pasteur
pipet, ice bath, separatory funnel, rotary evaporator, evaporating
dish, cotton for filtering, and UV-vis spectrometer.
The chemicals required are: 0.1 g. of H2TTP made previously, 20 mL
N,N-dimethylformamide, 0.16 g. hydrated copper acetate, distilled
water, 75 mL dichloromethane, hexane, toluene, ethyl acetate,
dichloromethane, and acetone for TLC plates.
Procedure
1. Measure out 0.1 g. of the H2TTP made previously into a 100 mL
...
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...aporates off the gel leaving open sites
where polar molecules can bond. When you let silica gel out in the
open, it will collect water molecules on it. Compounds would elute
faster down a column that has been heated at 150 degrees for 8 hours
because the gel would be dry.
3. A mixture of cis and trans isomers of the neutral complex Cr(CO)4[P(C6H5]2
is loaded onto a silica gel and eluted with CHCl3. Which isomer would
elute first, and
why?
The trans isomer would elute first.
References
Skoog Douglas; Holler F. James; Nieman Timothy A., Principles of
Instrumental Analysis, fifth edition, Thompson Learning: 1998.
UV-Vis Absorption Spectroscopy-Theory.
http://www.shu.ac.uk/schools/sci/chem/tutorials/molspec/uvvisab1.htm.
2. Cooper, M. M., Cooperative Chemistry Laboratory Manual, McGraw-Hill: New York, NY, 2009, p. 60.
Every 5 minutes, a small amount of mixture was dissolved in acetone (0.5 mL) and was spotted onto a thin layer chromatography (TLC) plate, which contained an eluent mixture of ethyl acetate (2 mL) and hexanes (8 mL). The bezaldehyde disappearance was monitored under an ultraviolet (UV) light. Water (10 mL) was added after the reaction was complete, and vacuum filtrated with a Buchner funnel. Cold ethanol (5 mL) was added drop-by-drop to the dried solid and stirred at room temperature for about 10 minutes. Then, the solution was removed from the stirrer and place in an ice bath until recrystallization. The recrystallized product was dried under vacuum filtration and the 0.057 g (0.22 mmol, 43%) product was analyzed via FTIR and 1H NMR
The complete experimental procedure is available in the General Chemistry Laboratory Manual for CSU Bakersfield, CHEM 213, pages 20-22, 24-25. Experimental data are recorded on the attached data pages.
The objective of this experiment was to perform extraction. This is a separation and purification technique, based on different solubility of compounds in immiscible solvent mixtures. Extraction is conducted by shaking the solution with the solvent, until two layers are formed. One layer can then be separated from the other. If the separation does not happen in one try, multiple attempts may be needed.
...ussion: Adsorption sites for salt as well as for alcohol are polar silanol groups (Fig 1c). As discussed earlier, alcohol is not adsorbed on all silanol groups (prefers isolated silanol group) and alcohol is more preferentially adsorbed than salt. So, anchorage of salt on the silica surface must be very distinct, reducing the possibility of irreducible mixed metal support formation. Also for substantial adsorption, silica gel has to be contacted with very concentrated salt-alcohol solution. In our opinion small amount of water cause ionization of alcohol which further induce ionization at silanol surface creating anionic sites suitable for esterification of ethoxy group. On the other hand, salt is mostly “associated” if the water is around 1-2% in the solution and the adsorbed salt will act as nucleation site for salt present mainly because of physical interaction.
Once the mixture had been completely dissolved, the solution was transferred to a separatory funnel. The solution was then extracted twice using 5.0 mL of 1 M
3.) Divide your 30g of white substance into the 4 test tubes evenly. You should put 7.5g into each test tube along with the water.
In our experiment we utilized the hydrate cobaltous chloride. Hydrates are crystalline compounds in which one or more molecules of water are combined with each unit of a salt. Cobalt (II) chloride hexahydrate is an inorganic compound which is a deep rose color in its hydrated form. As an inducer of
== Refer to, Chemistry Lab #1 – What’s the substance? However, I changed some of procedures during my experiment, here is the changes I made in this experiment: * I only used the toothpick to place a small amount of each sample on a separate piece of paper, instead of the spatula.
2. In the large beaker, put water and boil it completely. After that, remove the beaker from heat. 3. Sample tubes (A-D) should be labeled and capped tightly.
1-Butanol with intermediate polarity was soluble in both highly polar water and non polar hexane as 1-butanol can be either polar or non polar compound. 1-Butanol was polar based on the general rule of thumb stated that each polar group will allow up to 4 carbons to be soluble in water. Also, 1-butanol can be non polar due to their carbon chains, which are attracted to the non polarity of the hexane.
Heterocyclic chemistry is the branch of chemistry dealing with the synthesis, properties and applications of heterocycles. The name comes from the greek word “heteros” which means “different”. Any of a class of organic compounds whose molecules contain one or more rings of atoms with at least one atom (the heteroatom) being an element other than carbon, most frequently oxygen, nitrogen, or sulfur [1].
Plontke, R. (2003, March 13). Chemnitz UT. TU Chemnitz: - Technische Universität Chemnitz. Retrieved April 1, 2014, from http://www.tu-chemnitz.de/en/
Begin collecting samples with the pure hexane. Keep adding hexane so that the silica gel column does not run dry. Collect one 20 ml sample. Repeat with 90:10 hexane and collect 4 20-mL bottles. Repeat with 80:20 hexane and collect 2 20-mL samples.
For this experiment we used titration to standardize the exact concentration of NaOH. Titration is the process of carefully adding one solution from a buret to another substance in a flask until all of the substance in the flask has reacted. Standardizing is the process of determining a solutions concentration. When a solution has been standardized it is referred to as a standard solution. To know when a solution is at its end point an indicator is added to acidic solution. An indicator is an organic dye that is added to an acidic solution. The indicator is one color is in the acidic solution and another color in the basic solutions. An end point occurs when the organic dye changes colors to indicate that the reaction is over (Lab Guide pg. 141).