How will you convert (i) chloroethane to butane (ii) Methylamine to methyl isocyanide?

Converting chloroethane to butane and methylamine to methyl isocyanide involves specific chemical reactions. Here's how you can achieve these transformations:

(i) Converting Chloroethane to Butane:

Chloroethane (C2H5Cl) has two carbon atoms, while butane (C4H10) has four carbon atoms. To convert chloroethane to butane, you need to introduce two additional carbon atoms. One common method to achieve this is through a series of reaction steps involving elimination and substitution reactions. Here's a general outline:

Step 1: Dehydrohalogenation
Chloroethane can undergo a dehydrohalogenation reaction to form ethene (C2H4) and hydrogen chloride (HCl). This can be achieved using a strong base, such as sodium or potassium hydroxide (NaOH/KOH):

C2H5Cl → C2H4 + HCl

Step 2: Ethene Dimerization
Ethene can undergo a reaction called dimerization, in which two ethene molecules combine to form butane:

2C2H4 → C4H10

So, by combining these two steps, you can convert chloroethane to butane:
C2H5Cl → C2H4 + HCl
2C2H4 → C4H10

(ii) Converting Methylamine to Methyl Isocyanide:

Methylamine (CH3NH2) has an amine functional group (-NH2), while methyl isocyanide (CH3NC) has an isocyanide functional group (-NC). To convert methylamine to methyl isocyanide, you'll need to replace the amino group with an isocyanide group. One common method involves the Curtius rearrangement:

Step 1: Formation of Methyl Azide
Methylamine can be reacted with sodium azide (NaN3) to form methyl azide:

CH3NH2 + NaN3 → CH3N3 + NaOH

Step 2: Curtius Rearrangement
Methyl azide is then treated with a reagent like triphenylphosphine (PPh3) and an acid to undergo the Curtius rearrangement. This rearrangement results in the formation of an isocyanate intermediate, which upon heating or treatment with acid converts to the desired product, methyl isocyanide:

CH3N3 + PPh3 → CH3NC + N2 + PPh3O

Please note that both of these reactions involve specific reagents and conditions. Safety precautions and proper laboratory techniques are essential when working with chemical reactions. Also, chemical transformations may have side reactions or limitations, so it's important to consult reliable chemical literature or experts before attempting these reactions.