Tools of green chemistry

 Explain the Tools of green chemistry?

Ans...........
CHOICE OF STARTING MATERIAL:-it is therefore important to reduce the use of petrochemicals by using alternative starting materials which may be of agriculture /biological origin. For example ,some of the agricultural products such as corn, potato ,Soya and molasses are transformed through a variety of processes into products like textiles, nylon etc
CHOICE OF CATALYSTS:---certain reaction proceed much faster and at a lower temperature with the use of catalyst.heavy metal catalysts should be avoided as they can environmental problems and are toxic in nature.Following are some different types of catalysts are used

    ACID CATALYST:--Hydrogen fluoride an extremely corrosive hazardous and toxic chemical used in the preparation of linear alkyl benzenes has been replaced by a solid aciExplain the Tools of green chemistry?d catalysts fluorided silica aluminum catalyst
    POLYMER SUPPORTED CATALYST:--polymer super acid catalyst is obtained by binding aluminum chloride to sulfonated polystyrene.This is used for cracking and isomerisation of alkanes at 35degree C at atmospheric pressure
    PHOTO CATALYSTS:--Titanium oxide based photo catalytic system have been developed and are important for purification of polluted water, the decomposition of offensive Explain the Tools of green chemistry?odours, toxins, fixation of Co2 and decomposition of CFCS.

PHASE TRANSFER CATALYSTS:---PTC"S are soluble in water as awell as in the organic solvent.the PTC reaction, infact is a methodology for accelerating the reaction between water insoluble organic compounds and water soluble reagents.in chemistry a phase transfer catalyst a PTC is a catalyst that facilitates the migration of a reaction from one phase to another phase where reaction occurs. Ionic reactants are often soluble in aqueous phase transfer catalyst. By using a ptc process on can achieve faster reactions obtain higher yields, make fewer by products and eliminate dangerous solvents eliminate the need for expensive raw materials or minimize waste problems
   
     Example 1

 

Example 2

 

BIO CATALYSTS:--the moist important conversion in the context of green chemistry is with the help of enzymes.Enzymes are also referrd as biocatalysts and the transformation are referred to as biocatalyst conversation

 The biocatalytic conversations have many advantages in relevance to green chemistry. Some of these are given bellow

1:  Most of the reactions are performed in aqueous medium
2:  perform at ambient temperature and pressure
3:  the conversation are stereo specific

CHOICE OF REAGENT:-----for example conventional methylation reactions carried out in the presence of methyl halides or methyl sulphates. The toxicity of these compounds  and there environmental consiquences render this synthisis.hence a method was developed by Tundo to methylation active methylene compounds selectively using dimethylecarbonate(DMC) in which there are not any toxicity.

 Besides DMC, many polimer supported reagentes are used. Some such reagentsare given bellow

    Polymer supported chromic acid:--is used to oxide pramiry and secondry alcohals to carbonyl compoundes

Poly- N-Bromosuccinimide (PNBS) is an effecting brominating agent and used as benzylic and allylic brominating agent.

SOLVENT SELECTION:----the choice of solvent in a reaction or process should be given as much thought as the choice of reagent coumpondes. Solvents are often used in large quantities and eather end up as waste or need purification before recycling which is both inefficient in terms of energy and time.
Solvents are however sometimes essential and frequently careful choice will have beneficial effects both in terms reaction rate and selectively

MICROWAVE INDUCED METHOD FOR GREEN CHEMISTRY SYNTHESIS:--the main purpose of microwave are used for heating. It id brought about by transformation into heat of a part of energy contained in the electromagnetic waves. Normally polar molecules can involve in selective absorption Of microwave but not non polar molecules.
In the absence of electric field the dipoles are randomly oriented and molecules in Brownain movement.in the presence of electric feild all dipoles are lined together on sane direction the rapid reorientation produces homogeneous heating .This is the main advantage of microwave
ADVANTAGES OF MICROWAVE:--

  1.......It is clean, economical, efficient and safe procedure
  2.....Thus can led save time and money