Essay Example on Preparing Glassware for Synthesis: Cleaning, Washing & Drying

Introduction

In the first step, one needs to wash and rinse a 5mk round bottom flask, rubber septum and use three syringes and plungers with distilled water and acetone. Secondly, one needs to dry the washed equipment by placing them on the oven for thirty minutes. After that, one should remove the pieces and a preassembled drying tube to allow it to cool and prevent condensation. When the glassware is still warm, one needs to place a septum on the round bottom flask and assemble the syringes.

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Later on, one will insert a needle on the drying tube into the septum on the round bottom flask. After doing that, one will use the dry syringe s and 0.34 mL of dry 1-hexene through the septum into the round bottom flask and later on cool the flask down to 0o C using an ice bath. After one has cooled it for 5 minutes, one will use a second clean syringe and ass 1.0 mL of Borane in THF dropwise through the septum for 5 minutes.

Once after completing the addition of Borane, one needs to remove the flask from the ice and allow it to come to room temperature while swirling the mixture. Afterward, one will allow the mixture to remain constant while it is at room temperature for around 30 – 45 minutes while swirling it. Subsequently will add four drops of distilled water through the septum using a clean syringe. Later on, one should place the flask in a beaker and store it on a drawer for the next procedure.Oxidation procedure (Day two)

Take the flask from the drawer, while using a syringe add 0.60 mL of 3M NaOH to the reaction mixture and later on slowly add 0.60 mL of 30% H2O2 dropwise using a syringe for 10 minutes while swirling it. One should, later on, add a boiling chip to the mixture and attach it to the reflux adapter to the round bottom flask. Prepare a hot water bath and add the thermometer to monitor the boiling temperatures in order to keep the boiling water at a range of 40- 45 minutes for one hour. One should remove the reaction mixture and allow it to cool, later on, add 2.0mL of diethyl ether to the reaction mixture, mix the layers using a Pasteur pipet by drawing the mixture into the pipet, and rapidly remove it. One needs to transfer the mixture into a 15mL centrifuge tube. Using the Pasteur pipet, one should remove the aqueous layer and later on transfer it to a clean centrifuge tube.

One should add 2.0 mL of diethyl ether to the aqueous layer in order to extract the product and mix the layers with the Pasteur pipet and remove the top layer. Later on, repeat the procedure by adding 2.0 mL proportion of diethyl ether and combine it with the previous ether layer and wash the combined ether layers with 1.5 mL of 0.1 M HCL acid, mix the Pasteur pipet and later on remove the bottom layer and place it on the side. One should wash the ether layers with 1.0 mL proportions of distilled water, mix it, and remove each layer and set it aside. Transfer the layers to a clean Erlenmeyer flask, rinse the centrifuge with 1.0 mL of diethyl ether, and combine the rinse with another centrifuge tube. One should add 0.400 g of anhydrous Na2SO4 form, and add 0.200 g of the drying agent. Later on, using a clean 10 Erlenmeyer flask, one needs to transfer the ether leaving the Na2SO4 into the flask using a Pasteur pipet. Later on, rinse the Na2SO4 left in the original task with 1.0 mL of diethyl ether and transfer the rinse to the new flask and evaporate the ether by warming the flask on one's hands. One should way the flask for the mass of the product and run the FTIR spectra and make notes on what determines the products and dispose of all aqueous materials on the halogenated waste and later on clean up all glassware.

Discussion

The hydroboration–oxidation chemical reaction refers to a two-step hydration process of converting an alkene into alcohol that is neutral. The hydroboration oxidation method is also known as the anti-Markovnikov reaction, where a hydroxyl group tends to attach itself tp where the carbon is not well substituted.

Hydroboration Step

In the hydroboration step, it begins with the adding of Borane. In the chemical name, it is known as BH3 to an individual double bond. It will bring about the transfer of hydrogen atoms to the carbon atoms that is closer to the carbon bonds with the Boron atom (Elsherbini et al.). The chemical reactions need to be repeated twice in order to give put three alkalenes that tend to be attached to the Boron atom. Compound that forms after the addition of the three alkenes is referred to as trialkyl Borane (Elsherbini et al.). The trialkyl borane tends to be treated with water and hydrogen peroxide; thus, the boron carbon bonds get replaced with the carbon OH bonds. The conversion process of boron into boric acid can be observed, and the 1- hexene gets converted into 1 – hexanol. (Nagashima, et al.). The BH2 adds itself to alkene groups until the hydrogen atoms get transferred to the alkenes, and there are np hydrogens bonded with the boron atoms.

Oxidation Step

When the trialkyl borane is formed, the second process takes place. At this step, the boron atom gets attacked by the hydroperoxide ion. The R- group tends to be rearranged along with the pair of bond electrons next to the oxygen atoms

Conclusion

Alkynes can undergo hydroboration, and it tends to occur when the unevenly distributed carbon attacks the boron atom. In order to stop the reaction, one needs to use a bulky reagent. The oxidation process begins with the oxidization of alkyl borane into vinyl alcohol that belongs to the same group, such as alkene and OH group (Nagashima, et al). The hydroboration-oxidation chemical reactions refers to a two-stage hydration process that tends to transform alkenes to alcohols

Works Cited

Elsherbini, Mohamed, et al. "Selective hydroborationoxidation of terminal alkenes under flow conditions." Chemistry-A European Journal (2020). DOI:10.1002/chem.202001650.

Nagashima, Yoshiyuki et al. "Stereodivergent Hydroboration of Allenes." Chemistry, an Asian journal vol. 13,8 (2018): 1024-1028. DOI:10.1002/asia.201800134