Organic conversions relating to alkanes

Conversions related to alkanes :

                        Most of the students find organic conversions difficult .For them here is a simple scheme of how can we carry out conversions.

Conversions which are directly or indirectly related to alkanes:

These conversions start from alkane and end at alkanes.

All coloured blocks are functional groups which you can be obtained following this scheme .

R-X=alkyle halides

R-OH=alcohal

R-CHO=aldehyde

R-COOH=carboxylic acid

R-NO₂=nitro alkane

R-MgX=alkyle magnesium halide(Grignard reagent)

For furthure querries post your question and conversions will be uploaded soon.

Difference between adsorption and absorption

Difference between adsorption and absorption:

Adsorption: 

• Chemical or physical adhesion of molecules or substances to the surface.
• It implies adhesion when liquid or gas stick to the surface of adsorbent with the preservation of their physical state.
• It is a surface phenomenon
• It is exothermic process.
• It occur at low Temperature ,at high T desorption occurs.
• Surface(adsorbent) is solid state  mostly on which the molecules attach.
• There is a relation ship between pores at the surface of adsorbent and size of adsorbate.
• It can be temporary or permanent .
• Mono and multilayer can form.
• It is not uniform always proceeding toward equilibrium
• Its rate  is not same,decreasing till attaining equilibrium.
• e.g Adhesion (Adsorption) of leach or mosquito to the human body surface. 
• Molecules (adsorbate) can be separated easily because of surface adhesion and lose attachment.

 Absorption:

• Distribution of molecules or substances(liquid or gas) through out the bulk.
• It implies assimilation and occurs through the conversion of gas into liquid,liquid into solid hence they may lost their physical state.
• It is a bulk phenomenon.
• It is endothermic process.
• Temprature does not affect.
• Molecules absorb in gas or liquid phase very easily.
• No effect of sizes of particles and no pores on surface as it is the bulk phenomenon.
• Absorption leads to permanent reaction.
• No formation of layers.
• It is uniform process of absorption throughout the bulk.
• Its rate remains same through the process.
• e.g when leach or mosquito absorbs or sucks blood from human body.
• Molecules can not be separated as they are assimilated in the matrix(bulk).

                                                                                                                                                                                                                                      

What is Desorption :

Desorption :

                             

Desorption is a process of releasing of sorbed (adsorption or absorption) substances.Removal of adsorb substances means removal of those substances which adhere to the surface and removal of absorbed molecule means removal of those  which were assimilated in the bulk (matrix or solution under consideration).

Desorption incoperates both adsorption and absorption phenomenon.Concentration of molecules is not  always same on the surface or in the bulk , but always wants to attain equilibrium .When this equilibrium is not attained or faces some disturbance due to some external factors (T,P) then desorption occurs.

As it is understood that molecules move from higher concentration to lower concentration,If the molecule concentration is lower in bulk ,then the molecules( adsorb or absorb) move into bulk in order to saturate.

 When the  surface molecules leaves they may converted into gas or liquid .It arises due to difference in bulk and surface concentration .If the binding between adsorbate and adsorbent is weak, subtances leave the surface in adsorption and  bulk in absorption ..e.g  when you peel out the cocumber and then smear it with salt ,water comes out of it these water molecules which were absorbed  before smearing salt and now they are desorped.

The surface molecules linked  to each other, when heated molecules transfer heat  fom one molecule to other,it will  leads  to desorption .Hence temprature when raised then thermal desorption occur.The reason behind is equilibrium is disturbed as some molecules evaporated due to heating (changed their phase) .Leaving behind a system which will incoperate molecules either absorbed or adsorbed to attain stable state.

Desorption is also the ability of a substance to move freely in the bulk.More it is mobile less its chances to adsorb.Hence conduction of heat is easier.

Preparation and composition of sago waste as an adsorbent:

Preparation and composition of Sago waste as an adsorbent:

                                                                          

                                                         

Sago palm(Cycus revoluta) a green leafy ornamental plant http://en.wikipedia.org/wiki/Cycas_revoluta .It is mostly cultivated  due to its beautiful long green leaves .If it is ingested by man it will be very dangerous some species of it are extremely poisonous.It propagates mostly through seeds.

 Sago waste as an adsorbent:

 In a present study, sago waste being used up as an adsorbent. It is a waste biomass, inexpensive and easily available. On the other hand it is granular and having the ability to remove the contamination from the waste water.Certain dyes are compatible and sago waste have prooved to remove many toxic metals  from effluents and inreturn toxicity free waste water is obtained .

  

Firstly twig off all the leaves and spread all the leaves onto the paper. Keep all the leaves on sun exposure, to set dry. Later the dried leaves grinded to obtain powder of raw leaves. Further passed such dried powder from the sieve in order to get more refine powder.in the long run introduced the powder into oven at low temprature  and let allow the powder moisture free. Now the adsorbent is ready to use.Pack the adsorbent in an air tight container. The composition of sago palm: Trunk weight varies from 800 kg to 1250 kg and pith weight varies from 643-850 kilograms. The pith contains 20.2 -29% starch and 50-66% water, the remainder being 13.8-21.3 per cent. Calculated on the basis of dry matter, the pith contains 54- 60% starch and 40-46% of other dry matter. The bark or cortex varies from 25.7% -32% of the trunk. Regarding sago, the granular starch size ranges from about 5-80 micro meters with an average of 30 microns. About 90% of the starch has a particle size of between 20-40 microns. Sago starch consists of 27% amylose and 73% amylopectin. Its gelatinization temperature is 700 centigrade.

       

Banana peel is compatible to adsorb methylene blue dye:

Banana peel is compatible to adsorb methylene blue dye:

Methylene blue is the heterocyclic compound with a chemical formula C₁₆H₁₈N₃SCl .It appear as a solid ,odorless,dark green colour powder .On dissolution it forms blue colour solution.Once you find out the compatible adsorbent for the adsorbate then further experiments are very easy .Banana peel have acompatibility to adsorb many toxic contaminants ,heavy metals and dyes .Banana peel is compatible to remove methylene blue.When industries using dyes like ethylene blue ,methylene blue ,bromophenol ,alizarin red,alizarin yellow etc ,to colour their products discharge waste water .This effluent is a greatest threat to the life nearby .Also this water is translocated and enters in the nearby land and causes many problems there.In order to over come the problem waste biomass adsorbents are nowadays very efficient . Banana peels are one of them. Banana peel can adsorb cadmium ,chromium http://www.sciencedirect.com/science/article/pii/S092777650800502X,platinium nano particles http://www.sciencedirect.com/science/article/pii/S0927776510002857 etc 

Sr. No.	Name of Dye	Molecular Formula	Structure Formula
1.	Methylene Blue	C16H18ClN3SCl

Compatibility test and steps for compatibility test for adsorbent to adsorb various dyes .

Compatibility test for adsorbent to adsorb various dyes .

                                     Compatibility test is the procedure through which we can find whether the given adsorbent can adsorb the adsorbate well or not.Compatibility testing is a method or a test which is employed to seek out the compatibility of the given solute with respect to its solvent. Basically it is the test encompasses the property of the solute and check out the reactivity with its solvent.If a solute has granular structure/porous body will be more compatible with its solvent.Adsorption is a efficient and low cost technique used for the purification of waste water which is responsible for the contamination of water.Many textile and other industries using various kinds of dyes e.g methylene blue,ethylene blue,bromophenol,alizarin red, alizarin yellow,methyl orange, methyl red and many many more .All these dyes have different compatibilities with low cost biomass adsorbents as banana peel ,sago waste,peanut shell, tea waste, husks etc.To get the efficient results first check the compatibility and then use adsorbent for purification of waste water.

Steps for compatibility test:

   For Compatibility testing steps are followings;

1.      Firstly prepare the stock solution of the dye (methylene blue/ ethylene blue) i.e., in a volumetric flask dissolved 1000mg of weighted amount of dye into 1000ml of distilled water to make 1000 ppm stock solution. From stock solution pippet out 10ml and added 90ml of water in it to make 100 ppm solution.

2.      Fixed the lambda max.λ_max (maximum wavelength) of the dye and determine the absorbance of the blank solution i.e., 100ppm through spectrophotometer(1100-visible).

3.       Passed the fixed amount of adsorbent dose i.e.,1g and let allow the solution to stand for an hour.

4.       After an hour maintained pH of the solution and filter out the solution.

5.        Now note down the after absorbance at the λ _max (maximum wavelength) of the dye.

6.         Compare the before and after absorbance of the solutions.

7.          After absorbance should be less than before absorbance. This is the key point of the compatibility testing.

8.         If the value of after absorbance less than before absorbance then adsorbent is compatible with dye. Lesser the after absorbance more compatible will be the adsorbent.

    Hence compatibility test is determined

Composition of banana peel .

Composition of banana peel.

                     

Banana peel is the outer covering of banana .Peels form 18-30%of the total fruit and are a waste product.Peels are good sources of cartenoids ,polyphenols and certain bio active compounds which impart beneficial effects on human health. On average banana peels contain 6-9% dry matter of protein and 20-30% fibre(measured as NDF).40% starch is found in green plantains .This starch get converted into sugars when they are fully riped. 30% free sugar  is found in ripe bananas and about 15%  starch.Leucine ,valine phenylalanine and threonine are essential amino acid present in considerable quantities .Lysine was the limiting amino acid .The content of lipid varies from 2-10% and was rich in polysaturated fatty acids ,particularly linoleic acid and alpha linoleic acid .Potassium is the most significant element.Starch is more in plantain peel than in banana peel. As the maturation proceeds ,increase in sugar content occur with the decrease in starch due to degradation of starch under the action of endogenous enzymes.

 .Chemical composition of banana peel is carbohydrate ,fiber,potassium ,maganese, iron,sodium. Traces of polyphenoles ,ether extractives and tannic acid is also present in banana depending upon which species of it is used.Many experiments have shown that banana peels have good antioxident potential and can be used for water purification ,for the removal of many toxic metals like copper,lead,cadmium ,chromium and nano particles etc.Banana peels have good compatility to adsorb dyes methylene blue ,ethylene blue and bromophenol before disposal in the water these dyes should be treated with compatible adsorbent to remove their toxicity.