Skip to main content

Catalyst

> Introduction

- A substance while is increase or decrease the rate of reaction whithout taken in part any reaction is known as catalyst

- The mechanism of catalysis the freeenergy of activation is dowered by the presence of catalyst

- The catalst is promoting the reverde  reaction for example. platinum

- For the platinum is effective catalyst for the oxidation of Co² & Co³ they also found speedly decomposition of So³ in to So² & O²

-  The rate of reaction decrese by the presence of catalyst is called negative catalyst

-  For Example Nitric Oxide, Iodines

2.) Types Of Catalytic Reaction 

- There are two types of catalytic reation...

   1) Homogeneous Catalyst

    2) Heterogeneous Catalyst

- let us consider that a non catalytic biomolecular reaction proceed as follows..

A) Homogeneous Catalyst 

-  When the catalyst & raection substances are in the same phase is called homogeneous catalyst.

-  Homogeneous catalyst reaction may be gaseous & liquid.

-  Such types of reaction are used in Industry in batch or continus tank reaction

-  For  Examples

1) CH³COOCH³ + H²O  ----->  CH³COOH
    Methyl acetate                Acetic acid
    + CH³OH
                 
2) So²+ O² ---No(g)-->  So³g

3) 2Co + O² ---NO(g)--> 2Co²


B)  Heterogeneous Catalysts 

- When the catalysty and reaction substance are in the different phase is called heterogeneous catalyst

- The combination of H² & O² from water vapour is heterogeneous catalyst.

- The platinum is separation phase the reaction mixture.

-  For Example

1) So² + O² ---V²O5--> So³(g)

2) N² + 3H² ----Fe---> 2NH³

3) Co + 2H² ---Cu,Zn,--> CH³OH

4) water vapour ---Pt--> H² + O²

3.) Propetries Of Solid Catalyst : Contact Masses.

- The most important requirement of a good Industrial catalyst are

I)   It must be active in agiven traction

II)  It should be stable to the action of contact poision

III)  It should be cheap & have a high
mechanical strength

IV)  It Should be heat resistance

V)  It should be definite thermal conductivity.

> Factor Affecting Catalysis

1) Catalyst Activity 

- The pressure also affecte the product yield of a catalyst process in according with lechatelier's principal

- That is why an increase or a high pressure is widely used in many industrial catalyst processes

- For example in the synthesis of ammonia & methanol the pressure become the decisive factor when the catalyst activity & the product yield not high

2) Temperature 

- The effect of  temperature is not always clearly pronounce for eg. when the temperature is raised above a creation limit in the catalyst reaction of ammonia oxidation methenol & ethanol synthesis harmful side reaction being to take place.

- For  process including several reaction are especially if they have oppsite sing of their heat effect overall reaction is endothermic but the laws of endothermic processes

3) Concentration Reactants 

-The concentration of the reactants affects the rate of catalytic reaction in the same way as the rate of ordinary chemical reaction

-For eg. when a process is highly exothermic & it is difficult to remove all the step in the process are essentially the same as for the usal precipitation.

- catalyst contaning silica & alumina are essentially  suitable for preparations by gel formation because thair precipitation are of collidal nature.


4) Intensity Of Mixture 

- In some cases a prous material can be obtainec by mixing the components with water milling to the desired effect gain size drying & calcling

- A mixed magnesium & calcium oxide catalyst can thus be prepared. the carbonates are milled wet in a ball machine,extruded,dried & then reduced by a heating in an oven.

- This is important when cosily metals such as the platinum,nikal, & silver are used as catalyst.


Comments

Post a Comment

Popular posts from this blog

Types of rabbur and information about it.

 Rubber is a name of a matenrial which come Strate & Shrinkage. - Rubber is a polymer either peroduced by a natural Source Can be synthesis on an industusial scale. - Rubbeut is also known as elastomer is a high Polymeulr having elastic propenties. - Elasticity & rabberness is the most important Properties of rubber. - on strching it elongate to nearly 200% of its original dimentational &  quickely reaction to it's original Shape when Strching fouice is a remove. >   Importance of application of ruubber  properties of rubber(natural & synthetic rubber) 1)  Grood tensile Strength. 2) High flexibility 3) good electrical resistance 4) good chemical resistance 5) good Abrasion resistance 6) good resilience 7) high elasticity 8) low condudivity 9) low permeability to air, grases & Liquids. - Rubber are use manufacture of large no. of puroducts such as, tyres, v-belts, conveyor belts rubber lined tanks, m...

M.sc Sem-2 Manufacturing Of Glass & Types Of Glass And Information About It

                   >  Process - Glass are made by heating mixtune that nearly always consist of silica call & dry powder or metallic oxides. - Most glass are manufactun by a process in which raw-mateutials are converted at high temperature to a homogejeaus melts , that is then form in to an article. -  Raw mateutials are selecting acrourding the properties purity supply, cost etc . - Silica sand is most common in goradiant all most type of glasses.  - limp-Stones is a sourvr of colcium soda ash is Source of Sadium and bore and Boutic acid is Source of borone. - Broken gloss Usually termed as collected is used as a batch material to enhance glass melting and to resuce the amount of dust and other particular matter that aften a companies a batch mads exculsively from fresh raw-mateuial. - Tipically 10 to 151% of glass batch is the comprised of collect. - More efficient of operation as used in the c...

Industrial Production of MgSo4,CaSo4, Mg(OH)² & MgCo³ & Na²Sio³

1)  Industrial production of MgSo4,CaSo4, Mg(OH)² > Reaction                                     1)  Mgcl² + Ca(OH)²  ----->  Mg(OH)² +                                                            CaCl² 2)  Cacl² + H²So4  ------>  CaSo4 + 2HCL 3)  MgCl² + H²So4 ------> MgSo4 + 2HCL > Process  - In the industrial production of MgSo4 & CaSo4 first of all mixed salt bittern is first taken in a reactor. - Ca( OH)² from line treatment tank is also charge into the reactor. - Due to reactor precipitation of the Mg(OH)² is obtained. - filter the mass in filter press to remove precipitation of Mg(OH)² which is dry pulverised & packed. - Filtrate is further taken in a trea...