Save
Busy. Please wait.
Log in with Clever
or
show password
Forgot Password?
Don't have an account?  Sign up 
Sign up using Clever
or
Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account. Your email address is only used to allow you to reset your password. See our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
focusNode
Didn't know it?
click below
 
Knew it?
click below
Don't Know
Remaining cards (0)
Know
0:00
edit
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Zeolites

TermDefinition
What is a zeolite? Inorganic crystalline solid with high surface area, attributed to small pores (1-100A in diameter) present throughout structure. A mineral with a honeycomb-type structure and a unique "open" microporous molecular structure.
General structure of a zeolite They are an aluminosilicate framework structure with corner sharing SiO4 and AlO4 tetrahedra alternating throughout, in a lattice-like configuration.
Pore characteristics of a zeolite Sharply defined and shape selective. Act like molecular sieves.
Rules that dictate the build of zeolites Two aluminium ions cannot be adjacent to one another. Si/Al ratio of 1 to infinity.
Some properties of low Si/Al ratios Alkaline when in water, hydrothermally unstable, hydrophilic.
Some applications for natural zeolites Pollution control. Mining. Crops/Pastures. Horticulture. Stockfeeds. Aquaculture. Turf. Vermaculture.
Building of zeolites Structure of fused 4 and 6 membered rings.
How to control zeolite structure? Pore size and shape can be controlled by growing zeolites around a template.
Steps of zeolite synthesis To autoclave: sodium silicate, sodium aluminate, template, H2SO4 at 100-150C. Gels. Crystals: Filtering, washing, drying, calcination. Ion-exchange, drying, calcination. Zeolite.
Techniques for zeolite characterisation XRD, FTIR, Raman, surface area, XPS.
Shape-selective catalysis by zeolites Certain zeolites can be used to catalyse reactions and be specific to what product(s) is formed.
Reactant-selective Only one type of reactant molecule can be allowed to pass through the catalyst pores, due to size and shape.
Product-selective Only one type of product molecule can be allowed to pass through the catalyst pores, due to size and shape. Therefore, only a certain product is formed. "Observed" product
Applications of shape-selective catalysts Undesirable impurities can be continuously converted to easily removable compounds or harmless substances, the selectivity of a desired product can be increased and coke formation can be reduced.
What is Zeolite Y? ZY is a synthetic zeolite with structural type FAU, with a high Si/Al ratio. Ultra-stable Y.
Applications of Zeolite Y? FCC - Fluid CAtalytic Cracking is the process to "crack" heavy gas oils from larger molecules into small molecules, by breaking carbon bonds. Alkylation - Introduction of an alkyl group onto a molecule.
Green chemistry and zeolites Solid acid properties have been utilised extensively. Catalysts for: Friedels-craft acylation, salt-free esterfication of amino acids, green caprolactam process. Used in methanol to gasoline production.
Zeolite A Largest volume zeolite produced. Water softener in laundry detergents. Replaced harmful tri-phosphates.
Popular Chemistry sets

 

 



Voices

Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!
"Know" box contains:
Time elapsed:
Retries:
restart all cards