3.14, 3.15 & 3.16 Organic Synthesis, NMR and Chromatography

• Organic synthesis includes aliphatic organic synthesis, which puts all of the organic reactions that have been seen into one place.
• Organic synthesis requires knowledge of the reaction mechanisms, such as what chemicals react with one another to form another.
• NMR fires out radio waves at a specific frequency and a range of different frequencies.
• Nuclei can be shielded from the external magnetic field by electrons surrounding the nucleus.
• In NMR, when there is no magnetic field applied, the spin of the nucleon spins in random directions with no order.
• NMR measures the amount of energy absorbed by the nuclei, which is dependent on the environment surrounding the nucleus.
• When a magnetic field is applied in an NMR machine, some nuclei spin with the magnetic field and some spin against the magnetic field.
• The agents and conditions for aliphatic organic synthesis include potassium dichromate, sulfuric acid, and heat for alcohol to aldehyde; sodium borohydride, methanol, and water for aldehyde to alcohol; potassium dichromate, sulfuric acid, and reflux for alcohol to ketone; and concentrated sulfuric acid and phosphoric acid for alcohol to alkene.
• The carbon atom at the end has two environments, one due to its bond with a bromine and one due to its bond with a ch3.
• For an atom to be in the same environment, it must be bonded to an atom or group of atoms that are identical, as seen in NMR spectroscopy.
• The hydrogen environments in NMR spectroscopy can be different depending on the bonding arrangement.
• The molecule with the bromine in the middle has three carbon environments.
• The carbon atom bonded to a ch2 and a br has two environments.
• The purple molecule in the example has one environment.
• In the example with two bromine atoms, there are four hydrogen environments, all in the same environment due to symmetry.
• Carbon and violence are examples of environments in NMR spectroscopy.
• The influence of electrons on an atom can be affected by being next-door to an electronegative element, which will pull electrons away from the atom and leave it a little exposed, as seen in NMR spectra.
• The amount of electron shielding in an atom can vary depending on the groups of atoms adjacent to it, as seen in NMR spectroscopy.
• The shielding effect is the phenomenon where atoms with a good number of electrons around the nucleus and around the atom are more shielded than those which don't.
• Carbon NMR involves looking at the influence of the atoms next door to the carbon atom, as they determine the environment of the carbon atom.
• The environment of a nucleus is determined by the groups of atoms that exist near to it, as seen in NMR spectroscopy.
• Column chromatography is used for separating and purifying larger quantities of mixture, as TLC is only suitable for small samples.
• Purple dye is dyed and identified as purple.
• The RF value is calculated by dividing the distance traveled by the spots by the distance traveled by the solvent.
• Iodine is used as a locating agent to identify spots on the paper.
• The solvent continuously moves through the column in column chromatography.
• The RF values are fixed for each chemical, making it possible to identify the substance if the conditions of the experiment match those specified in the data book.
• Column chromatography involves packing a glass column with silica or alumina beads, which serve as the stationary phase.
• The number of spots on the plate indicates the number of chemicals in the mixture.
• The mixture or solvent, which is the mobile phase, runs through the column in column chromatography.
• The number of smaller Peaks in a splitting pattern corresponds to the number of hydrogens in the adjacent carbons.
• A triplet peak in the spectrum indicates two hydrogens on the neighboring carbon.
• The peak at two point one in the NMR spectrum suggests a ch3 group bonded to the C double bond.
• A quartet peak in the spectrum indicates three hydrogens on the neighboring carbon.
• The splitting pattern in NMR allows us to determine the structure of a molecule, which carbon 13 did not do.
• The peak at eleven point seven in the NMR spectrum indicates a carboxyl group.
• If a peak in the spectrum is a singlet, it means that there are no hydrogens on the neighboring carbon.
• The rule used in proton NMR is called the at n plus 1 rule, which states that the number of hydrogens plus one equals the number of smaller Peaks in the splitting pattern.
• In proton NMR, Peaks that split into smaller Peaks are called splitting patterns.
• Gas chromatography is mainly used in research but is also used in breathalyzers.