Propylene Glycol

Molecular Structure

Molecular Details

Molecular Formula	CH₃CH(OH)CH₂OH
Molecular Weight	76.09 g/mol
State	Liquid at standard conditions

Olefinverbund Integration

Chemistry & Engineering

Reaction Equation	C₃H₆O + H₂O → C₃H₈O₂
Thermodynamics	Exothermic hydration
Catalyst System	None/Thermal (high pressure) or Acid
Reactor Class	Liquid phase hydration reactor
Process Considerations	Food-safe antifreeze alternative.

Extraterrestrial Production Pattern

1. Propylene oxide + H₂O → propylene glycol
2. Non-catalytic hydrolysis at 150-200°C
3. Excess water to minimize dipropylene glycol
4. Vacuum distillation for purification

Applications

• Food-grade antifreeze
• Pharmaceutical solvent
• E-cigarette liquid base
• Cosmetics humectant

Reaction Diagram

Overall Reaction: C3H6O + H2O -> CH3CH(OH)CH2OH

Unit Operations

Process steps following chemical engineering unit operation principles:

Step	Operation	Description
1	PO/Water Mixing	Mix propylene oxide with water (15:1 H₂O:PO)
2	Hydrolysis	Non-catalytic at 150-200°C, 15-20 bar
3	Dehydration	Multi-effect evaporation
4	MPG Distillation	Vacuum distill monopropylene glycol
5	DPG/TPG Recovery	Recover dipropylene and tripropylene glycol
6	Finishing	Final purification for USP grade

S88 Batch Control Model

This module follows the ISA-88 (S88) batch control standard. Below is a simplified BatchML schema for educational purposes:

<?xml version="1.0" encoding="UTF-8"?>
<!-- ISA-88 Batch Control Model for Propylene Glycol -->
<!-- Educational schema - simplified for demonstration -->
<BatchML xmlns="http://www.wbf.org/xml/B2MML-V0600">
  
  <ProcessCell ID="PG_PLANT_CELL">
    <Description>Process cell for Propylene Glycol production</Description>
    
    <Unit ID="PG_PLANT">
      <Description>Main synthesis unit</Description>
      
      <!-- Equipment Modules -->
      <EquipmentModule ID="MIXER">
        <Description>Mixer</Description>
      </EquipmentModule>
      <EquipmentModule ID="REACTOR">
        <Description>Reactor</Description>
      </EquipmentModule>
      <EquipmentModule ID="EVAPORATOR">
        <Description>Evaporator</Description>
      </EquipmentModule>
      <EquipmentModule ID="MPG_COLUMN">
        <Description>Mpg Column</Description>
      </EquipmentModule>
      <EquipmentModule ID="DPG_COLUMN">
        <Description>Dpg Column</Description>
      </EquipmentModule>
      <EquipmentModule ID="FINISHING">
        <Description>Finishing</Description>
      </EquipmentModule>
    </Unit>
  </ProcessCell>
  
  <MasterRecipe ID="PG_PLANT_RECIPE">
    <Description>Master recipe for Propylene Glycol</Description>
    <ProductID>PROPYLENE_GLYCOL</ProductID>
    
    <UnitProcedure ID="PG_PLANT_UP">
      <Description>Unit procedure for synthesis</Description>
      
      <Operation ID="OP_01">
        <Description>Operation 1</Description>
        <Phase ID="MIX">
          <Description>Mix phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_02">
        <Description>Operation 2</Description>
        <Phase ID="HYDROLYZE">
          <Description>Hydrolyze phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_03">
        <Description>Operation 3</Description>
        <Phase ID="EVAPORATE">
          <Description>Evaporate phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_04">
        <Description>Operation 4</Description>
        <Phase ID="DISTILL_MPG">
          <Description>Distill Mpg phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_05">
        <Description>Operation 5</Description>
        <Phase ID="RECOVER_DPG">
          <Description>Recover Dpg phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
      
      <Operation ID="OP_06">
        <Description>Operation 6</Description>
        <Phase ID="FINISH">
          <Description>Finish phase</Description>
          <PhaseLogic>
            <Step ID="STEP_1"><Action>Initialize</Action></Step>
            <Step ID="STEP_2"><Action>Execute</Action></Step>
            <Step ID="STEP_3"><Action>Complete</Action></Step>
          </PhaseLogic>
        </Phase>
      </Operation>
    </UnitProcedure>
  </MasterRecipe>
  
</BatchML>

**Key S88 Concepts:**
- **Process Cell**: The physical grouping containing all equipment for this process
- **Unit**: The major equipment that performs the synthesis
- **Equipment Modules**: Individual pieces of equipment (reactors, columns, etc.)
- **Unit Procedure**: The sequence of operations to produce the product
- **Phases**: The lowest level of procedural control (e.g., REACT, SEPARATE, PURIFY)

Key S88 Concepts:
• Process Cell: Physical grouping containing all equipment
• Unit: Major equipment performing synthesis
• Equipment Modules: Individual pieces (reactors, columns, etc.)
• Phases: Lowest level of procedural control (REACT, SEPARATE, etc.)

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This Synthesis Module is part of the 100chemicals Olefinverbund — an integrated chemical production network designed for extraterrestrial civilization on Moon and Mars.