What was not green about this experiment? Minimum two suggestions with reference

Question

What was not green about this experiment? Minimum two suggestions with reference to a specific GCP number. THEORY Recrystallization is a common laboratory practice used to purify a compound The first st is to decide on an appropriate solvent. An ideal solvent is one in which the solid to be Purified is insoluble at room temperature, but much more soluble at a higher temperature. The cold relativel solvent must also be able to dissolve impurities that are to be removed. Finding the correct solvent some that are more soluble then the compound to be purified are easily removed by crystallization, since they will be retained by the mother liquor (the liquid remaining after crystallization has taken place). Impurities with solubility similar to the substance being purified that are present in low concentrations will also remain in the solution, and can be easily removed. If there are mechanical impurities such as sand, dust or cork that do not dissolve even upon heating, the hot solution can be gravity filtered to remove these. In the case of coloured impurities, a small amount of decolourising carbon (charcoal) can be added to the hot solution. The carbon is then removed as a mechanical impurity. amounts of decolourising carbon the be avoided, since it may the compound that is being purified. To ensure that most of substance being purified can be recovered, it is essential that the least amount of hot solvent to the sample is used. It is good practice to err on the side of insufficient solvent, since more can be easily added in small increments until enough is present. Sometimes, an ideal solvent cannot be found. In such a case, a mixture of two solvents, a solvent required. A t-pair is made up of two mutually soluble liquids, one that dissolves the substance easily and solvent that dissolves it sparingly. The solid to be dissolved in a minimal volume of the first solvent at room temperature. The second solvent is then added gradually until the solution becomes turbid. Heating followed by cooling typically leads to a successful recrystallization. Some examples of common solvent-pairs include water and ethanol, cyclohexane and ethyl acetat and glacial water. The melting point will be determined using a Mel-Temp apparatus the lab. A "p sample of acetanilide is generally one in which the melting point is within three degress Celsius of expected UNDERSTANDING THE EXPERIMENT You begin the experiment with acetanilide, which is contaminated with traces of water is luble Red, 5% by weight sand and 5% by weight benzoic acid. The goal of this experiment to remove these impurities To tart off, the sample needs to be dissolved. This will get the soluble impurities, benzoic acid and Methyl Red as well which adsorbs the the acetanilide into solution. Next, the sample is treated with charco impurities, namely sand and charcoal (as well as the Methyl Red adsorbed by the and The solution now containing acetanilide and benzoic acid is allowed to cool slowly, acetanilide just more soluble in water then acetanilide and found in crystallizes. B acid is lower concentration, so it will remain mother liquor. in the Vacuum filtration is used to collect the

Explanation / Answer

Recrystallization and purification of acetanilide

The process does not qualify being green as it uses organic solvent for the recrystallization process which is not green solvent.

Also loss of acetanilide during filtration makes the process loose material and the recivery is not 100%.

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