Most of the chemical act as disinfectant.However some chemical used in proper concentration for appropriate duration act as sterilants.The chemical agents used on skin or wound are called antiseptic.

1.First it should have wide spectrum of activity

2.It should be stable and should have long shelf life

3.Should be non toxic,non irritable,non allergenic 

4.should have High penetrating power

5.They should be non corrosive

6.Should not have undesirable odour 

7.should not leave stain 

8.should have faster action

9.should act even in the presence of organic matter 

10.should be easily available

11.should be in expensive

12.act on wide range of temperature and pH 

Chemical method includes alcohol, aldehyde, phenol, halogen, heavy metals, surface active agent, dye, oxidizing agent and gases like ethylene oxide, formaldehyde gas,beta propiolactone 

Alcohol

Mode of action: Alcohol act on cell membrane causing it's disruption.Further, they cause coagulation of protein,thus, killing the micro organisms.

Example: The alcohol that are commonly used are iso propyl alcohol, ethyl alcohol and methyl alcohol.

Application:A 70%aqueous solution is used and is commonly called as sprit.It is commonly used to sterilize the skin.It is also used to disinfect the surface and to sterilize the clinical thermometer.Methyl alcohol is used to disinfect inoculation hood as it has the ability to kill even fungal spores.

Disadvantages:They are highly volatile and,thus evaporate quickly leave the disinfected area for contamination.They are also highly inflammable.

Aldehydes

Mode of action: The aldehyde have the ability to kill all micro organisms including spores.Thus,they are considered as the sterilization agent.They damage the nucleic acid and protein by the process of alkylation.

They act through alkylation of amino, carboxyl or hydroxyl group, and damage nucleic acid.

Example: formaldehyde and glutaraldehyde 

Application normally a solution of 40%formaldehyde in water is used.The formalin is used for surface disinfection and fumigation of room, chamber, operation theatre, biological safety cabinet,wards,sick room,etc.

The glutaraldehyde is used as 2%glutaraldehyde solution to sterilize thermometer, cystoscope,bronchoscope, centrifuge, anaesthetic equipment and various other equipment used in hospital.An exposure of at least 3 h at alkaline pH is required for action by glutaraldehyde.

Apart from this,2%formaldehyde is used to disinfect wool and to disinfect animal hair in leather industries.

Disadvantages:The formaldehyde vapours are irritant and require neutralization with ammonia.It has poor penetration leave non volatile residue and its activity is reduced in the presence of protein.Glutaraldehyde requires alkaline pH.