Difference of chemical properties of p-chlorotoluene

1. molecular structure difference

The molecular structure of p-chlorotoluene is a Cl and a CH3 group attached to the benzene ring. Its molecular formula is C6H5ClCH3 and its molecular weight is 114.16g/mol. The molecular structure of bromotoluene is similar to that of p-chlorotoluene, except that Cl is replaced by Br, the molecular formula is C6H5BrCH3, and the molecular weight is 121.01g/mol. Halotoluenes replace Cl with other halogen atoms, such as I or F.

The difference in molecular weight directly affects the physical properties of the substance, such as melting point and boiling point. The melting point of p-chlorotoluene is 51 ° C., and the boiling point is 177 ° C.; the melting point of bromotoluene is 58 ° C., and the boiling point is 198 ° C.; the melting point and the boiling point of halogenated toluene (such as hexafluoro-p-chlorotoluene) vary with different halogen types and structures.

2. physical properties comparison

The density of p-chlorotoluene is 1.496g/cm³, slightly higher than the 1.492g/cm³ of bromotoluene. This is because the atomic weight of Cl (35.5) is slightly higher than that of Br (80), but after Br replaces Cl, the molecular weight increases, resulting in a smaller change in density. The density of halogenated toluene varies depending on the type of halogen, for example, iodotoluene has a higher density than methyl bromide because of the greater atomic weight of iodine.

In terms of vapor pressure, the vapor pressure of p-chlorotoluene is about 12 mmHg, and that of bromotoluene is about 8 mmHg. The vapor pressure of halotoluene varies with the type of halogen, but the overall trend is to increase with the increase of halogen atomic weight.

3. chemical reaction characteristic analysis

The chemical reaction of p-chlorotoluene under different conditions showed different characteristics. For example, under light conditions, p-chlorotoluene may undergo photolysis to produce dichlorotoluene and methane. The decomposition products of brominated toluene under illumination are different from those of p-chlorotoluene, and the decomposition products include a brominated xylene and methane. This difference stems from the different activities of Cl and Br in the photochemical reaction.

Under acidic conditions, p-chlorotoluene may react with some alkaline substances to form the corresponding salts. The reaction characteristics of bromotoluene are similar to those of p-chlorotoluene, but the reaction activity is higher due to the stronger electronegativity of bromine. The reactivity of halogenated toluene varies depending on the type of halogen, and the reactivity of iodine is higher.

4. application field comparison

p-chlorotoluene is mainly used in the fields of organic synthesis, dye intermediates and auxiliaries. It is used as a raw material or catalyst in the synthesis process, and has good stability and dispersion. The application of bromotoluene in organic synthesis is less, mainly because of its low substitution reaction activity. Halogenated toluene is more used in the synthesis of specific fine chemicals, especially where higher halogen substitution reactivity is required.

In terms of environmental protection, the environmental friendliness of p-chlorotoluene is better than that of bromotoluene, because the atomic weight of Cl is small, and its chemical properties are relatively stable, so it is not easy to cause pollution to the environment. The environmental friendliness of halogenated toluene varies with the type of halogen, and the stability of iodotoluene is poor, which may cause environmental pollution.

5. summary and application suggestions

Through the comparative analysis of the chemical properties of p-chlorotoluene, bromotoluene and halogenated toluene, it can be seen that there are significant differences in molecular structure, physical properties, chemical reaction characteristics and application fields. In practical applications, suitable compounds should be selected according to specific needs. For example, in the synthesis process requiring higher halogenation reaction activity, toluene bromide should be preferred, but in the case of higher environmental requirements, methyl chloride or methyl iodide may be more appropriate.

In practical applications, chemical professionals need to understand the differences in the properties of each compound in order to ensure safety and environmental protection, while improving production efficiency.