Wednesday, July 29, 2020
- NaClO3 + CsCl → CsClO3 + NaCl
- Molar mass of cesium chloride = 168.36 grams per mole
- 10 grams of cesium chloride = 0.059396531 moles
- Molar mass of sodium chlorate = 106.44 grams per mole
- 0.059396531 moles of sodium chlorate = 6.3221 grams of sodium chlorate
Tuesday, July 21, 2020
- Synthesis of Cs3UO2(SCN)5
- 1 mole uranyl sulfate trihydrate, 3 moles of cesium thiocyanate (1.5 moles cesium sulfate),
- UO2SO4 + Ba(SCN)2 → UO2(SCN)2 + BaSO4
- Ba(SCN)2 + Cs2SO4 → 2CsSCN + BaSO4
- 1 gram of uranyl sulfate trihydrate
- Molar mass = 420.138
- 0.002380 moles
- Molar mass of barium thiocyanate dihydrate = 289.53 grams per mole
- 0.002380 moles of barium thiocyanate dihydrate = 0.689130 grams
- Molar mass of cesium sulfate = 361.87 grams per mole
- 0.00357 moles of cesium sulfate = 1.29 grams cesium sulfate
- 0.00357 moles of barium thiocyanate = 1.033
Friday, July 3, 2020
- Synthesis of Coumarin from Salicylaldehyde, Acetic Anhydride, and Triethylamine (Source: Vogel's Textbook of Practical Organic Chemistry 1040)
- Synthesis of Coumarin from Salicylaldehyde, Acetic Anhydride, and Sodium Acetate (Source: US Patent US3631067A)
- In a 200 ml. round-bottomed flask equipped with a stirrer, a 12" x 1" Vigreux column, water-cooled condenser and receiver, 346 g. of salicylaldehyde and 70 g. of sodium acetate were mixed to a smooth slurry under ambient conditions, and 185 g. of acetic anhydride was added to the mixture.
- The reaction mixture was gradually heated from room temperature to C. in one hour and another 185 g. of acetic anhydride was added.
- The reaction mixture was then heated to 180 C. during the second hour, another g. of acetic anhydride was added and the temperature was maintained at 180 C. during the third hour.
- As the reaction temperature approached 160 C., acetic acid was distilled from the mixture, and 393 g. was collected over the three-hour reaction.
- At the end of the reaction, the reaction mixture weighed 567 g. and was analyzed to contain 40.5% coumarin.
- 288 grams of the mixture was charged into a 500 ml. round-bottomed flask as the molten liquid at 70 C. and fractionally distilled under 8 mm. of Hg up to a final pot temperature of 210 C.
- Of the 202 g. of material distilled, 110.5 g. was coumarin to account for 94.7% of the coumarin initially present and the remaining 91.5 g. were by-products and coumarin precursors. The residue contained less than 0.6% coumarin and about 50% sodium acetate.
- In the same manner as described by the example above, coumarin can be prepared by the Perkin reaction by reacting 1 mole or less of sodium acetate per mole of salicylaldehyde in the presence of 1 to 4 moles of acetic anhydride per mole of salicylaldehyde at a temperature of up to about 200 C. The product of this reaction can then be fractionally distilled at a temperature of up to about 250 C. under reduced pressure. Also in the same manner, other alkali metal acetates may be employed in the reaction to give essentially the same results. For example, potassium acetate or cesium acetate may be employed in place of sodium acetate
- The conditions of the fractional distillation may vary widely. In the preferred distillation, temperatures of about to about 250 C. are employed, with to 190 C. being especially preferred. At temperatures below 80 C., the reaction mixture is usually very viscous or solid and cannot be readily distilled. At temperatures above 250 C., decomposition of the desired product is possible without the compensating benefits of a better distillation.
- Within the preferred temperature conditions, subatmospheric pressure is required to distill the reaction mixture. Such pressure may vary widely so long as the pressure is low enough to maintain a reasonable rate of distillation. Generally, pressures of about 1 mm. to about 300 mm. of Hg are required with pressures of 5 mm. to about 100 mm. being preferred.
- In the process for preparing coumarin by reacting salicylaldehyde, alkali metal acetate and acetic anhydride, the improvement comprising maintaining the molar concentration of the alkali metal acetate at or below the concentration of salicylaldehyde employed in the reaction and then separating the coumarin from the reaction mixture by distillation.
- The process of claim 1 wherein less than 0.8 mole of alkali metal acetate is reacted per mole of the salicylaldehyde.
- The process of claim 2 wherein 0.2 to 0.6 mole of alkali metal acetate is reacted per mole of the salicylaldehyde.
- The process of claim 1 wherein the alkali metal acetate is sodium acetate
- The process of claim 1 wherein 1 to 4 moles of acetic anhydride are reacted per mole of the salicylaldehyde.
- The process of claim 1 wherein the coumarin is distilled from the reaction mixture at 80 to 250 C
- The process of claim 1 wherein the coumarin is distilled from the reaction mixture at a pressure of 1 to 300 mm. Hg.
Wednesday, July 1, 2020
- Synthesis of Ammonium Selenocyanate via Potassium Selenocyanate
- 1.7 grams of red selenium = 0.02153 moles of red selenium
- One fourth molar equivalent potassium ferrocyanide = 0.0053825 moles needed = 2.2735 grams of potassium ferrocyanide
- 0.02153 moles of ammonium sulfate = 2.845 grams ammonium sulfate
- Experiment recorded in BTS video 3.
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