Organic Chemistry II

Clean glassware is important in organic synthesis. Organic synthesis turns a readily available reagent into a more valuable product. When glassware is dirty, it can affect the reaction and make it harder to isolate the final product.

This lesson shows how chemists keep glassware spotless for better lab work. It covers cleaning methods used to remove organics, metals, grease, and salts. These steps help reduce contamination before and during synthesis.

Nucleophilic substitution reactions replace a leaving group on a carbon atom with a nucleophile. A nucleophile is an electron-rich Lewis base. These reactions are a core idea in organic chemistry, and they help explain how many carbon-based compounds change.

This lesson compares the two main pathways, SN1 and SN2. SN1 means substitution, nucleophilic, first-order kinetics. SN2 means substitution, nucleophilic, second-order kinetics. The video shows the subtle differences between these reaction...

Carbonyl reduction with IR monitoring shows how chemists track a reaction while choosing the right reducing reagent. The focus is on controlling reactivity and selectivity during molecule synthesis. That balance helps chemists pick reagents for a specific task.

The experiment uses carbonyl compounds to study their reactivity. It also examines hydride-reducing reagents, which donate hydride ions during reduction. IR spectroscopy is used to follow the reaction as it happens. This lets students...

Grignard reagents are useful organometallic compounds for building carbon-carbon bonds. This experiment shows how to make a Grignard reagent from magnesium and an alkyl halide. It then uses that reagent in a reaction with a carbonyl compound.

A nucleophilic attack on the carbonyl is carried out to form a secondary alcohol. This step shows a common use of Grignard reagents in organic synthesis. The reaction demonstrates how a new carbon-carbon bond can be formed during the process.

n-Butyllithium must be measured carefully before it is used in a chemical reaction. This experiment shows a simple titration method for finding its accurate concentration. The reagent is an organolithium compound, so it needs special handling in the lab.

n-Butyllithium is very sensitive to air and moisture. If it is exposed to either one, its quality can change. For that reason, the titration should be done regularly before the reagent is added to a reaction.

The procedure also includes...

A Dean-Stark trap is special glassware used to remove water during a reaction. It collects water by azeotropic distillation, which separates water along with vapor from the reaction mixture.

In many reactions, collecting water is useful because it can push the equilibrium toward the products. This matters in reversible reactions that make water as a byproduct. According to Le Chatelier's principle, a change in temperature, pressure, concentration, or volume causes a reversible reaction to...

Ozone can be used to break an alkene and form useful carbonyl products. In this chemistry experiment, ozonolysis is shown by making vanillin from isoeugenol.

Ozonolysis is an oxidation reaction between ozone and an alkene. It is a common method for preparing aldehydes, ketones, and carboxylic acids. The reaction in this demonstration shows how a carbon-carbon double bond can be cut and converted into a smaller product.

The experiment also highlights two important lab tools and conditions. It...

Organocatalysis uses small organic molecules to speed up chemical reactions. In this experiment, the reaction setup shows how enamine catalysis works. The catalyst is used in substoichiometric amounts, so only a small amount is needed to drive the reaction forward.

This approach is different from transition metal catalysis and biocatalysis. Transition metal catalysis uses metals as catalysts, while biocatalysis uses enzymes. Organocatalysis offers a separate path for making reactions happen.

Palladium-catalyzed cross coupling is a key method for building carbon-carbon bonds in organic chemistry. This experiment shows the concept behind that chemistry and the setup of a typical reaction.

These reactions have changed how synthetic chemists make molecules. They help chemists form bonds in new and more efficient ways. Because of that, palladium-catalyzed cross coupling is widely used in the fine chemical and pharmaceutical industries.

For high school students, this reaction shows how...

Solid-phase synthesis builds a target compound while the starting molecule stays attached to a solid support. In Merrifield's method, the reactant molecule is bound to a resin and then carried through a series of chemical reactions. This Nobel Prize winning approach is especially useful for making compounds step by step.

A key advantage of solid-phase synthesis is easy cleanup after each reaction. Excess reagents and byproducts can be washed away because the target compound remains bound to...

Chalcone hydrogenation is shown as an example of an alkene hydrogenation reaction. The experiment converts chalcone into 3-phenylpropiophenone. It highlights how hydrogen can add across a carbon-carbon double bond under catalytic conditions.

Palladium on carbon, or Pd/C, is used as a heterogeneous catalyst. A heterogeneous catalyst is one that is in a different phase from the reactants. In this setup, a balloon supplies the hydrogen atmosphere needed for the reaction.

Polymers are made of macromolecules built from repeating units called monomeric units. These large molecules are an important part of modern life. They appear in many everyday materials.

One of the first important polymers was nylon. Nylon is a polyamide, which means it has amide groups in its structure. It became widely used in products such as toothbrushes and stockings.

The melting point of a crystalline solid is an important property in chemistry. It helps identify how a solid behaves when it changes from a crystal to a liquid.

Melting point can also be used to check the purity of a known compound. A pure sample usually melts at a characteristic temperature range, which makes this property useful for comparison.

In addition, the melting point gives important information about the stability of the crystals that form. For this reason, it is a key measurement...

Infrared spectroscopy helps identify an unknown compound by showing which functional groups are present. It uses infrared (IR) light, so it is also called vibrational spectroscopy. The spectrum gives a pattern that can be compared with known group signals to narrow down the compound's identity.

In this experiment, an IR spectrometer is used to collect the spectrum of a neat sample of the unknown. The sample is analyzed with attenuated total reflection, or ATR, sampling. This method makes it...

A polarimeter measures the optical rotation of a sample. Optical rotation is the amount that a sample turns polarized light. This makes the instrument useful for studying substances that are optically active.

Optically active samples rotate the plane of polarized light in one of two directions. A clockwise rotation is called dextrorotatory and is labeled d or (+). A counterclockwise rotation is called levorotatory and is labeled l or (−).