The key difference between isomerization and hydroisomerization is that isomerization refers to the conversion of the structure of one compound to its isomeric structure whereas hydroisomerization is the conversion of one isomeric form into another of alkane hydrocarbons via an alkene intermediate
Isomers are chemical compounds having the same chemical formula but different chemical structures. There are several different forms of isomers, and they have different chemical and physical properties due to the difference in the structure.
CONTENTS
1. Overview and Key Difference
2. What is Isomerization
3. What is Hydroisomerization
4. Side by Side Comparison – Isomerization vs Hydroisomerization in Tabular Form
5. Summary
What is Isomerization?
Isomerization is the chemical process in which one isomeric form converts into another isomeric form. Some chemical compounds have only one isomer; thus, the isomerization of these compounds refers to the conversion of its structure into its isomeric form. But some chemical compounds have more than one isomeric form. Here, the isomerization refers to the conversion of one isomeric form into any of its other isomeric forms. The new compound (isomer) forms with the same chemical composition but different atomic connectivity or configuration.
Figure 01: Isomerization of Vinyl Norbornene
An example is the conversion of butane into isobutene. Butane is a straight-chain hydrocarbon structure. Isobutene is a branched structure. This isomerization can be achieved by the heat treatment of butane (about 100 degrees Celsius) in the presence of a suitable catalyst. In this process, the atomic connectivity changes; therefore, chemical and physical properties also change.
In alkenes, the most common form of isomerization is the cis-trans isomerization. Here, atomic connectivity doesn’t change that much because when cis isomer converts into trans isomer, only the substituent groups attached to the double bond changes. In addition, we can observe the isomerization process among inorganic compounds as well. Here, isomerization of transition metal complexes is the most common form.
What is Hydroisomerization?
The term hydroisomerization refers to the conversion of one isomeric form into another of alkane hydrocarbons via an alkene intermediate. This type of chemical reaction is specifically important in oil refining processes. Recently, the studies on hydroisomerization of long-chain paraffin for the production of branched alkenes have obtained a wide recognition.
Hydroconversion plays an important role in the petroleum industry. It has many significant applications in crude oil refining steps. Hydroconversions are in two main types as hydrocracking reactions and hydroisomerization reactions. The prefix hydro- comes because these reactions are carried out in the presence of hydrogen gas. In hydroisomerization, the properties of the feedstock are improved via the transformation of normal hydrocarbons into branched structures which has the same number of carbon atoms.
What is the Difference Between Isomerization and Hydroisomerization?
Isomerization is the conversion of one isomeric form to another. Therefore, the key difference between isomerization and hydroisomerization is that isomerization refers to the process of conversion of the structure of one compound to its isomeric structure whereas hydroisomerization is a type of isomerization where isomerization of alkane hydrocarbons occurs via an intermediate alkene.
The following table summarizes the difference between isomerization and hydroisomerization.
Summary – Isomerization vs Hydroisomerization
Isomers are chemical compounds having the same chemical formula but different chemical structures. Isomerization is the conversion of one isomeric form to another. Therefore, the key difference between isomerization and hydroisomerization is that isomerization refers to the process of conversion of the structure of one compound to its isomeric structure whereas hydroisomerization is a type of isomerization where isomerization of alkane hydrocarbons occurs via an intermediate alkene.
Reference:
1. “Isomerization.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 19 Apr. 2018, Available here.
2. “Isomerization.” Wikipedia, Wikimedia Foundation, 31 July 2019, Available here.
Image Courtesy:
1. “VNEtoENE” By Smokefoot – Own work (Public Domain) via Commons Wikimedia