Question

Write equations for the reaction of ethylene oxide with methanol in the presence of a little \(\mathrm{H}_{2} \mathrm{SO}_{4} ;\) (b) methanol in the presence of a little \(\mathrm{CH}_{3} \mathrm{O}^{(-)} \mathrm{Na} \oplus ;\) (c) aniline.

Short answer

The three reactions of ethylene oxide are as follows: 1. With methanol in the presence of H2SO4: \[ \mathrm{C_{2}H_{4}O + CH_{3}OH \xrightarrow[H_{2}SO_{4}]{} C_{3}H_{8}O_{2}} \] 2. With methanol in the presence of CH3O(-)Na+: \[ \mathrm{C_{2}H_{4}O + CH_{3}OH \xrightarrow[CH_{3}O^{-}Na^{+}]{} C_{3}H_{8}O_{2}} \] 3. With aniline: \[ \mathrm{C_{2}H_{4}O + C_{6}H_{5}NH_{2} \rightarrow C_{8}H_{11}NO} \]

Step-by-step solution

Identify reactants and products

In this reaction, the ethylene oxide (C2H4O) reacts with methanol (CH3OH) in the presence of a small amount of sulfuric acid (H2SO4), which acts as a catalyst. The product of this reaction is ethoxymethanol (C3H8O2).

Write the reaction equation

The reaction equation can be written as follows: \[ \mathrm{C_{2}H_{4}O + CH_{3}OH \xrightarrow[H_{2}SO_{4}]{} C_{3}H_{8}O_{2}} \] Step 2: Reaction of ethylene oxide with methanol in the presence of a little CH3O(-)Na+

Identify reactants and products

In this reaction, the ethylene oxide (C2H4O) reacts with methanol (CH3OH) in the presence of a small amount of CH3O(-)Na+ (sodium methoxide), which acts as a catalyst. The product of this reaction is also ethoxymethanol (C3H8O2).

Write the reaction equation

The reaction equation can be written as follows: \[ \mathrm{C_{2}H_{4}O + CH_{3}OH \xrightarrow[CH_{3}O^{-}Na^{+}]{} C_{3}H_{8}O_{2}} \] Step 3: Reaction of ethylene oxide with aniline

Identify reactants and products

In this reaction, the ethylene oxide (C2H4O) reacts with aniline (C6H5NH2). The product of this reaction is N-phenylethanolamine (C8H11NO).

Write the reaction equation

The reaction equation can be written as follows: \[ \mathrm{C_{2}H_{4}O + C_{6}H_{5}NH_{2} \rightarrow C_{8}H_{11}NO} \]

Key concepts

Ethylene Oxide Reactions

Ethylene oxide is a fascinating compound with a sweet, ether-like odor, often used as an intermediate in the production of other chemicals. Its triangular ring structure makes it quite reactive, especially when it encounters certain nucleophilic or acidic environments.
When ethylene oxide reacts, its strained ring can open up, readily engaging nucleophiles like methanol or aniline, facilitating the formation of new bonds.
In general, these reactions often involve catalysts, which assist in breaking the ring open to allow for subsequent attachment of the nucleophile.

• For example, when ethylene oxide reacts with methanol and a bit of sulfuric acid, the ring opens up to create ethoxymethanol.
• Similarly, when reacting with aniline, the nitrogen atom attacks, leading to the formation of N-phenylethanolamine.

These reactions are straightforward yet brilliant examples of the versatility of ethylene oxide in organic synthesis.

Catalysis in Organic Chemistry

In organic chemistry, catalysis plays a critical role in facilitating reactions that might otherwise occur very slowly or not at all. Catalysts increase the rate of a reaction without being consumed, providing an alternate pathway with a lower activation energy.
In the case of ethylene oxide reactions with methanol, sulfuric acid acts as a catalyst. It assists by protonating the ethylene oxide, which in turn increases the electrophilicity of the molecule, making it more susceptible to attack by methanol. Furthermore, using sodium methoxide ( CH_3O^(-)Na^{+} ) as a catalyst helps in similar fashion, increasing the reactivity by forming a better leaving group.

• Catalysts are crucial as they enable reactions under milder conditions and often improve yields.
• They may also allow for greater selectivity in reactions, leading to the production of the desired product selectively.

Nucleophilic Reactions

Nucleophilic reactions are key parts of organic chemistry where a nucleophile donates a pair of electrons to form a chemical bond with an electrophile. These reactions are foundational to understanding how molecules interact and transform.
In the case of ethylene oxide, the oxygen in the epoxide is protonated, which then opens up the possibility for a nucleophilic attack. Methanol acts as a nucleophile when the sulfuric acid is present, attacking the positively charged carbon in the oxirane ring.

• This process breaks the strained ring and forms a new bond, converting ethylene oxide into ethoxymethanol.
• Similarly, in the reaction with aniline, the nitrogen atom of aniline attacks, facilitating the opening of the ring and forming N-phenylethanolamine.

Understanding these interactions helps in predicting the outcomes of complex organic transformations.

Role of Catalysts in Organic Reactions

Catalysts are critical to organic reactions as they not only improve the efficiency but also the practicality of chemical processes. They work by providing an alternative reaction pathway that requires lower activation energy, thus speeding up the reaction significantly.
In our ethylene oxide reactions, catalysts like sulfuric acid and sodium methoxide play pivotal roles. By lowering the energy barrier, they ensure that the reaction proceeds swiftly and effectively.

• This is especially important in industrial settings where time and yield are crucial factors for economic viability.
• Moreover, catalysts can affect the selectivity of a reaction, guiding it towards the preferred products rather than unwanted by-products.
• In some cases, they also make it possible to conduct reactions at lower temperatures or pressures, which can save energy and reduce costs.

By understanding and leveraging the role of catalysts, chemists can design efficient and economical pathways for synthesizing desired compounds.