Polymerization Process and Catalysts Quiz
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Questions and Answers

What is the recommended pH for the reactor before adding vazo?

  • 500
  • 900
  • 1000
  • 700 (correct)

Which reducer is primarily used to initiate the polymerization reaction?

  • Sodium Metabisulfate
  • Monr's Salt (correct)
  • Sodium Sulfite
  • Sodium Persulfate

What is the minimum reaction time for the TBHP thermal catalyst?

  • 1 minute
  • 30 seconds (correct)
  • 5 minutes
  • 10 seconds

What is one of the byproducts formed from the thermal degradation of vazo 64?

<p>TMSN (D)</p> Signup and view all the answers

How does increasing the amount of redox catalyst affect the reaction kinetics?

<p>Results in faster kinetics (B)</p> Signup and view all the answers

What is the impact of copper on the polymerization process?

<p>Inhibits polymerization (C)</p> Signup and view all the answers

What is the purpose of the cyclone in the process?

<p>To capture good products for further processing (C)</p> Signup and view all the answers

What must be done to preserve the stability of thermal catalysts?

<p>Store in cold storage (B)</p> Signup and view all the answers

What is the specific gravity of the solution to be weighed in the salt concentration procedure?

<p>500 (A)</p> Signup and view all the answers

Which component is used as a neutral charge in the charges section?

<p>Acrylamide (A)</p> Signup and view all the answers

What is the boiling point condition mentioned in the R9 Tenportive section?

<p>95° Before Boiling Point (D)</p> Signup and view all the answers

What is the purpose of using purified water mentioned in the REDOX section?

<p>To ensure no minerals interfere with the catalyst (B)</p> Signup and view all the answers

How long should the line be flushed during the salt concentration procedure?

<p>5 seconds (D)</p> Signup and view all the answers

What effect does chelated iron have on reactions compared to unchelated iron?

<p>Acts as a catalyst and accelerates the reaction (A)</p> Signup and view all the answers

Which method is typically used for hydrolysis in reactions?

<p>Caustic substances (C)</p> Signup and view all the answers

What is the primary reason for poor solubility in polymers?

<p>Excessive temperatures during drying and polymerization (C)</p> Signup and view all the answers

What happens to a polymer chain during hydrolysis?

<p>It converts to an anionic acrylic acid tail (B)</p> Signup and view all the answers

What is the concern if the reaction temperature exceeds 100°C?

<p>Water converts to steam and expands the gel (D)</p> Signup and view all the answers

What is the consequence of high crosslinking in polymers?

<p>Decreased solubility (C)</p> Signup and view all the answers

What effect does running reactions too quickly have on the viscosity level?

<p>It causes a low UL viscosity. (D)</p> Signup and view all the answers

At what temperature do most reactions start?

<p>O°C (B)</p> Signup and view all the answers

What characterizes 'branching' in polymer chemistry?

<p>Increases viscosity without raising molecular weight (C)</p> Signup and view all the answers

What is defined as the unreacted or un-polymerized monomer molecules in polyacrylamide gel?

<p>Free monomer (B)</p> Signup and view all the answers

Which ingredient is NOT mentioned as part of the initial mix for polymerization in the reactor?

<p>Acetone (A)</p> Signup and view all the answers

What happens if the temperature in the reactor peaks above the boiling point of water?

<p>The gel can be forced violently out of the reactor. (B)</p> Signup and view all the answers

What causes the primary characteristics of the polymer product, charge, and molecular weight?

<p>The polymerization process. (D)</p> Signup and view all the answers

What is the result of adding too much monomer and not enough water in the reactor?

<p>The reactor peaks at too high of temperature. (A)</p> Signup and view all the answers

What might be indicated by differences in temperature readings from reactor temperature probes?

<p>Malfunctioning equipment or probes. (B)</p> Signup and view all the answers

What is a consequence of longer polymer chains in the product?

<p>They make drying the polymer harder without causing solubility problems. (B)</p> Signup and view all the answers

What triggers the initiation step in polymerization?

<p>The addition of the reducer from redox (D)</p> Signup and view all the answers

What is a consequence of having poor sparge pressure or flow-rate?

<p>Inadequate mixing of catalyst (A)</p> Signup and view all the answers

Which of the following is NOT a cause of termination in polymerization?

<p>Excessive heat in the reactor (C)</p> Signup and view all the answers

What is the primary role of sparging in polymerization?

<p>To displace oxygen in the reactor (A)</p> Signup and view all the answers

What is the impact of excess Versenex 80 in a reaction?

<p>It chelates copper and iron completely (C)</p> Signup and view all the answers

What problem can arise if a leak occurs in the nitrogen line during sparging?

<p>Oxygen entry causing initiation issues (A)</p> Signup and view all the answers

What happens if a solution of acrylamide is supplied with copper metal in it?

<p>Premature initiation is inhibited (B)</p> Signup and view all the answers

What occurs during the propagation phase of polymerization?

<p>Thermal catalysts drive the chain reaction (A)</p> Signup and view all the answers

What is the primary purpose of the gel hopper?

<p>To maintain a consistent flow of product to the granulator (D)</p> Signup and view all the answers

What happens when the gel hopper dips below the set point?

<p>The automatic sequences will refill the gel hopper (B)</p> Signup and view all the answers

What could indicate a problem if a normally easy-to-pre-grind product is hard to grind?

<p>The gel is too cold or the UL is too high (D)</p> Signup and view all the answers

How does the pre-grinder facilitate the grinding process?

<p>By tearing the gel into smaller pieces using screws (B)</p> Signup and view all the answers

What is a safety concern to keep in mind when working with the gel hopper?

<p>Entering the gel hopper without following confined space procedures (C)</p> Signup and view all the answers

What could happen if the feed to the granulator is inconsistent?

<p>Non-uniform drying (B)</p> Signup and view all the answers

What is the role of the grinding aid, Lubchopnos PK 455?

<p>To make gel easier to grind (A)</p> Signup and view all the answers

What is a sign of malfunctioning load cells on the gel hopper?

<p>Incorrect weight reading in the DCS (B)</p> Signup and view all the answers

Flashcards

Redox Reaction

A chemical reaction involving the transfer of electrons between reactants, resulting in a change in oxidation states.

Oxidizers

Substances that accept electrons in a redox reaction, causing the oxidation of another reactant. Examples include Sodium Persulfate, Tert-Butyl Peroxide (TBHP), and Potassium Bromates.

Reducers

Substances that donate electrons in a redox reaction, causing the reduction of another reactant. Examples include Sodium Metabisulfate (MBS), Sodium Sulfite, Mohr's Salt, and Sodium Formaldehyde Sulfoxylate (NFAFS).

Induction Time

The amount of time it takes for a polymerization reaction to start, measured by the temperature change on a reaction vessel. It varies with molecular weight: lower weight = shorter time, higher weight = longer time.

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Thermal Catalyst

A type of catalyst used in polymerization reactions that accelerates the reaction without requiring high temperatures. Examples include VAZO and JA-044.

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Thermal Degradation

The process of gradual chemical breakdown of thermal catalysts caused by exposure to heat, leading to the formation of free radicals and potentially toxic byproducts like TMSN.

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Hypo

A component of the polymerization process responsible for controlling the molecular weight of the polymer. It contributes to the overall viscosity of the solution.

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Catalyst Mix Times

The amount of time taken to mix each catalyst into the reaction vessel, crucial for optimal reaction efficiency. Each catalyst has a specific mixing duration.

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Initiation (in Polymerization)

The process of a reducer being added to a monomer solution, initiating a chain reaction that forms polymers.

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Propagation (in Polymerization)

The continuous growth of polymer chains as monomers bind to reactive sites.

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Termination (in Polymerization)

The termination of polymer chain growth due to the absence of monomers, the combination of two free radicals, or disproportionation.

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Auto Initiation

Unwanted polymerization that can occur when leftover heat from a previous reaction triggers the reaction before it's intended.

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Sparging

Injecting nitrogen gas into a reactor to remove oxygen, which inhibits polymerization.

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Versenex 80

A chelating agent that binds to copper and iron, controlling their availability in the polymerization process.

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Chelating Agent

A catalyst that speeds up the polymerization reaction.

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Excess Versenex 80

Excess chelating agent (Versenex 80) removes copper and iron, preventing unintended polymerization.

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Free Monomer

The amount of unreacted monomer molecules in a polyacrylamide gel solution. It is a measure of the acrylamide that has not been converted into polyacrylamide.

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Reactor

The vessel where liquid monomers are mixed and polymerized into a gel.

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Polymerization

The process of converting monomers into a polymer chain. It starts by removing oxygen and adding a catalyst.

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Molecular Weight

A key factor determining the characteristics of the final polymer product. It refers to the length of the polymer chains.

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Viscosity

A measure of the gel's ability to flow. High viscosity means the gel is thick and sticky, while low viscosity means the gel is runny.

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Solubility

A critical factor in determining the gel's stability and ability to be dried. It relates to the length of the polymer chains.

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Peak Temperature

A measurement of the temperature reached during the polymerization process. It is critical to ensure the reaction proceeds safely and effectively.

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DTank Sample Analysis

A technique used to troubleshoot reactor problems. It involves analyzing gel samples to identify the cause of any issues.

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Product Solubility

The measure of a polymer's ability to dissolve in water. Poor solubility can be caused by excessive temperatures during drying or polymerization.

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Hydrolysis

A chemical reaction where water interacts with another substance to form two or more new substances. In polyacrylamide production, hydrolysis converts the neutral amine group to an anionic acrylic acid tail, giving the polymer chain a negative charge.

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Cross-linking

A phenomenon that occurs when the polymer chains become excessively cross-linked, leading to reduced solubility and a gummy consistency. It's generally undesirable in polyacrylamide production.

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Branching

Increases the molecular weight of the polymer without significantly increasing its viscosity. It can improve solubility and processing characteristics.

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Time

The rate at which temperature changes over time. Measured using a graph with temperature on the Y-axis and time on the X-axis.

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Temperature

The starting temperature of most polymerization reactions. It influences the rate of reaction and potential side reactions.

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LPLH-Steam Jacket Reactor

A specific type of reactor used for polymerization. It is equipped with a steam jacket that regulates the temperature for optimal reaction progress. This jacket allows for precise control of heat transfer to the reactor vessel.

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What is the purpose of the Gel Hopper?

The Gel hopper is used to maintain a constant flow of product to the granulator, ensuring a consistent feeding rate.

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How does the Gel hopper work?

The Gel hopper is designed to maintain a consistent weight of product on the dosing screw, which feeds the granulator. This set point is critical for uninterrupted product flow.

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Sparging in Polymerization

A process used to remove dissolved oxygen from the liquid monomer solution before polymerization. It involves injecting nitrogen gas into the reactor, creating an oxygen-free environment, and preventing undesirable side reactions during the polymerization process.

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What happens when the Gel hopper dips below the set point?

The Gel hopper's automatic sequences within the DCS system ensure that the hopper is refilled when the weight dips below the set point, preventing an interruption in product flow.

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TBHP (tert-Butyl Hydroperoxide)

A specific chemical compound used as an initiator in polymerization reactions. It is responsible for starting the polymerization chain reaction. This substance contains a free radical and is added to the liquid monomer solution to initiate the polymerization process.

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What is the primary function of the pre-grinder?

The pre-grinder's main purpose is to break down large pieces of gel into smaller, more consistent pieces, ensuring a better flow through the granulator.

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How does the pre-grinder work?

The pre-grinder uses screws to tear the gel into smaller pieces. The weight of the gel, combined with the rotating screws, creates the grinding action.

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Salt Concentration Measurement

The process of measuring the salt concentration in a solution. It involves taking a sample of the solution, weighing it, and then calculating the specific gravity. The specific gravity value is then used to determine the salt concentration.

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What other functions does the pre-grinder have besides pre-grinding?

The pre-grinder handles post-treating gel, blending dust, and reworking product, expanding its role beyond simply breaking down gel.

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What impact does gel temperature have on pre-grinding?

The pre-grinder struggles to grind cold gel because it is more rigid and difficult to break down. Ideally, the gel should be hot for efficient pre-grinding.

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How can gel pre-grinding be made easier?

Adding a grinding aid like Lubchopnos PK 455 helps to lubricate the gel, making it easier to pre-grind. It is typically added during the pre-grinding process.

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Study Notes

Process Overview

  • Raw materials are prepped before entering the reactor.
  • Reactor operation involves mixing, reactions, and temperature control.
  • Reaction times vary, depending on molecular weight.
  • Gel exiting the reactor is processed and cooled.

Catalyst Mix Times

  • Vazo is prepared via a 30-minute spin.
  • AZDN (catalyst) mix times: 5 minutes
  • VerSenex (co-reactant) mix times: 3 minutes

Reduction Reactions

  • Oxidizer: Sodium Persulfate
  • Reducers: Mohr's Salt, Tert-Butyl Peroxide (CTBHP), Potassium Bromate, Sodium Metabisulfate (MBS), Sodium Sulfite, Sodium Formaldehyde Sulfoxylate (CNAFS)

PH and Neutralization

  • PH is 700
  • Neutralization occurs in the reaction process.

Viscosity Control and Molecular Weight

  • Hypo is used to control molecular weight.
  • Different polymers have different molecular weights.

Tank Sizes and Weights

  • DTANK - 26,000 kg
  • 3,000 L reactor used.
  • 3,500 mL reaction volume.

Thermal Degradation

  • Thermal catalyst degradation produces toxic byproducts, like TMSN.
  • Different catalysts have different degradation rates at various temperatures

Polymerization Steps & Inhibitor

  • Polymerization begins when the reducer is added.
  • Oxygen inhibits reaction hence, nitrogen sparging is crucial.
  • Reaction time depends on molecular weight.

Auto Initiation

  • Issues can arise with improper dissolution tank reaction control.
  • Left-over catalyst can trigger auto-initiation.
  • Catalyst mixing and inconsistent rates lead to erratic reaction curves.

###Chelating Agents

  • Versenex 80 is used as a chelating agent.
  • Versenex 80 is used to control reactions by binding transition metals
  • Excessive Versenex 80 can also be used as a catalyst

Product Solubility

  • Solubility is a product feature affected by temperature & pressure.
  • High temperatures lead to poor solubility.
  • Excessive branching decreases solubility.

Hydrolysis

  • Involves water reacting with a substance.
  • Hydrolysis can result in higher charges on polymer.
  • Temperature is a crucial factor to control during hydrolysis reaction

Kinetics

  • Reaction rate depends on temperature, measured over time using X-Y graphs.
  • Reaction time scales with molecular weight of polymer.

Free Monomer

  • Free monomers are unreacted monomers.
  • Free monomer levels affect polymer quality.

Reactor Operation

  • Reactor operation involves charging, stirring, reacting, and dumping gel.
  • Specific temperature and time parameters optimize the reaction

Reactor Trouble Shooting

  • Reactor liners can wear out, resulting in poor reaction control; electro-polishing or Teflon lining helps.
  • High temperatures could indicate problems.
  • Difference in temperatures between probe or tank could signal poor probe calibration.

Gel Hopper

  • Consistent feed to granulator via weight control mechanism.
  • Automatic filling process regulated by weight measurements in the tank.
  • Safety procedures for hopper entry are crucial.

Pre-Grinder

  • Pre-grinding breaks down the gel into smaller pieces for even drying.
  • Product consistency depends on gel hardness and consistency.
  • Grinding is difficult for products with high cationic content

Post-Treatment

  • Post-treatment (e.g., sodium sulfate) reacts the monomer.
  • Prevents issues with post-reaction.
  • Helps achieve even mixing in the gel.

Other notes

  • Specific chemicals (e.g. span 80, Vazo, TBHP, etc.) are used in different stages of the process.
  • Various pieces of equipment and materials are used for the process, such as pumps, tanks, and measuring instruments.
  • Multiple steps include mixing, reacting, and measuring or adjusting parameters.
  • Different process parameters or process problems are outlined throughout the notes.
  • Specific values for PH, temperature, molecular weights, time values, etc., are included in the notes along with specific chemical or equipment names.

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Polymerization Reactions PDF

Description

Test your knowledge on the polymerization process, including pH levels, reducers, and thermal catalysts. Understand the role of various components like vazo, copper, and the cyclone in reaction kinetics. This quiz covers essential concepts that are crucial for mastering polymer engineering.

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