All the reagents and solvents were obtained from standard suppliers. The 2:1 water:methanol was prepared by the Carleton College stockroom and methanol was degassed with argon with the use of a Schlenk Line, but the rest of the reagents and solvents were used with no further purification. The final step of the synthesis was performed in an inert atmosphere provided by a Schlenk Line. The 1H and 13C spectrums and COSY, DEPT, and HMQC experiments were collected with a Bruker Avance III HD 400 MHz High-Performance Digital NMR Spectrometer. Cobalt(II) bromide hydrate (2.170 g, 9.17 mmol) was dissolved in acetone (50 ml) which formed a dark blue solution. Dimethylglyoxime (2.209 g, 19 mmol) was added to the solution turning it dark red-brown. The solution was held under a gentle stream of air for 30 minutes and a green precipitate formed. The solution was cooled in an ice bath then vacuum filtered and washed with cold acetone (twice with 15 ml) to yield the green precipitate (1) (2.85 g, 5.97 mmol, 83.9% yield). …show more content…
Water (125 ml) was added to the solution then cooled in an ice bath for 10 minutes. The brown crystals (2) were collected by vacuum filtration and dried (2.407 g, 5.37 mmol, 90.3%
The percent yield of products that was calculated for this reaction was about 81.2%, fairly less pure than the previous product but still decently pure. A carbon NMR and H NMR were produced and used to identify the inequivalent carbons and hydrogens of the product. There were 9 constitutionally inequivalent carbons and potentially 4,5, or 6 constitutionally inequivalent hydrogens. On the H NMR there are 5 peaks, but at a closer inspection of the product, it seems there is only 4 constitutionally inequivalent hydrogens because of the symmetry held by the product and of this H’s. However, expansion of the peaks around the aromatic region on the NMR show 3 peaks, which was suppose to be only 2 peaks. In between the peaks is a peak from the solvent, xylene, that was used, which may account to for this discrepancy in the NMR. Furthermore, the product may have not been fully dissolved or was contaminated, leading to distortion (a splitting) of the peaks. The 2 peaks further down the spectrum were distinguished from two H’s, HF and HE, based off of shielding affects. The HF was closer to the O, so it experienced more of an up field shift than HE. On the C NMR, there are 9 constitutionally inequivalent carbons. A CNMR Peak Position for Typical Functional Group table was consulted to assign the carbons to their corresponding peaks. The carbonyl carbon, C1, is the farthest up field, while the carbons on the benzene ring are in the 120-140 ppm region. The sp3 hybridized carbon, C2 and C3, are the lowest on the spectrum. This reaction verifies the statement, ”Measurements have shown that while naphthalene and benzene both are considered especially stable due to their aromaticity, benzene is significantly more stable than naphthalene.” As seen in the reaction, the benzene ring is left untouched and only the naphthalene is involved in the reaction with maleic
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.
Triphenylmethyl Bromide. A 400 mL beaker was filled with hot water from the tap. Acetic acid (4 mL) and solid triphenylmethanol (0.199 g, 0.764 mmol) were added to a reaction tube, with 33% hydrobromic acid solution (0.6 mL) being added dropwise via syringe. The compound in the tube then took on a light yellow color. The tube was then placed in the beaker and heated for 5 minutes. After the allotted time, the tube was removed from the hot water bath and allowed to cool to room temperature. In the meantime, an ice bath was made utilizing the 600 mL plastic beaker, which the tube was then placed in for 10 minutes. The compound was then vacuum filtered with the crystals rinsed with water and a small amount of hexane. The crude product was then weighed and recrystallized with hexane to form fine white crystals, which was triphenylmethyl bromide (0.105 g, 0.325 mmol, 42.5%). A Beilstein test was conducted, and the crystals produced a green to greenish-blue flame.
Afterwards, we conducted crystallization to evaporate the liquid in an attempt to detect the presence of a salt. Before stating which of the potential
This was allowed to mix for a few minutes; a little excess water was used to ensure that sodium bromide was fully dissolved. This mixture was placed in an ice bath while continuing to stir. 1.3 ml (24.39 mmols) of concentrated sulfuric acid was added dropwise. The flask was removed from the ice bath and heated to reflux for 1 hour while continuing to stir. The resulting top layer was transferred to a conical vial in which 1.5 mL (22.51 mmols) of 80 % sulfuric acid was added. 2.0 mL of water was added to allow a layer to form. The bottom layer was removed and transferred to another conical vial in which 2.0 mL of saturated sodium bicarbonate was added. The bottom, organic layer, was transferred to a conical vial. Calcium chloride, a drying agent, was used to collect the remaining aqueous layer that
8. Continue stirring. Record the temperature at which crystals begin to appear in the solution.
[9] 2009, “CRC Handbook of Chemistry and Physics, 90th edition,” American Chemical Society CNC Press, Boca Raton, pp. 631-637
The second reaction had copper (II) nitrate reacting with sodium hydroxide in a precipitation reaction, Cu(NO3)2 (aq) + 2 NaOH (aq) → Cu(OH)2 (s) + 2 NaNO3 (aq). When the 20 milliliters of 6.0 M NaOH was added to the neon blue beaker with the copper (II) nitrate, the extremely light blue color darkened, turning to a darker blue color. Within the solution, an Orbeez-like consistency formed, which was the precipitate, forming copper (II) hydroxide.
Methyl benzoate (0.20 ml), Sulfuric acid (0.45 mL of 18 M), and a spin vane was added to a 5 mL conical vial. An air condenser is attached and clamped to allow proper stirring. A second ice bath was made to hold a 3-ml conical vial of Sulfuric acid (0.15 ml of 18M), and Nitric acid (0.15 ml of 16M). This was added dropwise at two and half minutes per drop to the 5 mL conical vial. This was done slowly so as not to produce TNT. Once completed, the 5 mL vial containing the solution was allowed to warm up to room temperature and sat for 15 minutes undisturbed. Two grams of ice was placed in a 30 mL beaker in which the solution was poured over it. The solution was rinsed with cold water and suction filtered when the ice was melted. The crystals were washed with cold water (2 - 1.0 mL), and methanol (0.3 mL). The product was recrystallized using methanol and allowed to dry. The final beige crystals were weighed, and tested for quality.
In terms of polarity we discovered that magnesium oxide ,calcium carbonate and “ unknown 2” are polar enough to dissolve in water and not dissolve in hexane. Salicylic acid ,benzoic acid and “unknown 1” have similar polarities as both did not dissolve in water and hexane. As for pH, the salicylic and benzoic acid crystals were extremely acidic. Magnesium oxide was slightly acidic while calcium carbonate was slightly basic. In terms of the unknowns, both were neutral.
The procedure for this experiment can be found in Inorganic Chemistry Lab Manual prepared by Dr. Virgil Payne.
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
Ostwald was appeared to be the first to explain the relationship between supersaturation and spontaneous crystallization. The relationship between the concentration and temperature is schematically shown in Figure 1. Extensive research has been carried out to explain the relationship between supersaturation and spontaneous crystallization. The lower continuous line is the normal solubility curve for the salt concerned. Temperature and concentration at which spontaneous crystallization occurs have been represented by the upper broken curve, generally referred to as the supersolubility
Inorganic chemistry–II (Structure and mechanism in inorganic and organometallic chemistry, bonding, group theory, basic solid-state chemistry, and spectroscopic techniques.
Step 6 was repeated with boiling tube #2 and a warm thermometer (after being placed in the hot water bath) was placed into the solution in boiling tube #1. The boiling tube was held up to the light and the first sign of crystallization was observed As the instant crystallization began, the temperature was observed and