Butadiene

Molecular Structure

Molecular Details

Molecular Formula	C₄H₆
Molecular Weight	54.09 g/mol
State	Gas at standard conditions

Olefinverbund Integration

Chemistry & Engineering

Reaction Equation	C₄H₁₀ → C₄H₆ + 2H₂ (Dehydrogenation) or 2C₂H₅OH → C₄H₆ + 2H₂O + H₂ (Lebedev)
Thermodynamics	Strongly endothermic dehydrogenation
Catalyst System	Chromium/Alumina (Catofin) or MgO-SiO2 (Lebedev)
Reactor Class	Adiabatic fixed bed with cyclic regeneration or multi-tubular
Process Considerations	The Lebedev process (ethanol-to-butadiene) is istorically significant and ideal for bio/ISR-ethanol feedstocks on Mars.

Extraterrestrial Production Pattern

1. Fischer-Tropsch synthesis to produce C4 hydrocarbons
2. Catalytic dehydrogenation of n-butane/butenes
3. Extractive distillation for purification
4. Storage under pressure or refrigeration

Applications

• Styrene-butadiene rubber (SBR)
• Polybutadiene rubber
• ABS plastics
• Nylon intermediates (adiponitrile)

Reaction Diagram

Overall Reaction: C4H10 -> C4H6 + 2H2

Unit Operations

Process steps following chemical engineering unit operation principles:

Step	Operation	Description
1	C4 Feed Preparation	Prepare mixed C4 stream from steam cracker
2	Extractive Distillation	NMP or ACN solvent extraction
3	Solvent Recovery	Strip butadiene from solvent
4	Purification	Remove acetylenes and C5+ impurities
5	Inhibitor Addition	Add TBC to prevent polymerization
6	Refrigerated Storage	Store at -4°C under pressure

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 Butadiene -->
<!-- Educational schema - simplified for demonstration -->
<BatchML xmlns="http://www.wbf.org/xml/B2MML-V0600">
  
  <ProcessCell ID="BUTADIENE_EXTRACTION_CELL">
    <Description>Process cell for Butadiene production</Description>
    
    <Unit ID="BUTADIENE_EXTRACTION">
      <Description>Main synthesis unit</Description>
      
      <!-- Equipment Modules -->
      <EquipmentModule ID="FEED_SYSTEM">
        <Description>Feed System</Description>
      </EquipmentModule>
      <EquipmentModule ID="EXTRACTIVE_COLUMN">
        <Description>Extractive Column</Description>
      </EquipmentModule>
      <EquipmentModule ID="STRIPPER">
        <Description>Stripper</Description>
      </EquipmentModule>
      <EquipmentModule ID="PURIFIER">
        <Description>Purifier</Description>
      </EquipmentModule>
      <EquipmentModule ID="INHIBITOR_SYSTEM">
        <Description>Inhibitor System</Description>
      </EquipmentModule>
      <EquipmentModule ID="STORAGE">
        <Description>Storage</Description>
      </EquipmentModule>
    </Unit>
  </ProcessCell>
  
  <MasterRecipe ID="BUTADIENE_EXTRACTION_RECIPE">
    <Description>Master recipe for Butadiene</Description>
    <ProductID>BUTADIENE</ProductID>
    
    <UnitProcedure ID="BUTADIENE_EXTRACTION_UP">
      <Description>Unit procedure for synthesis</Description>
      
      <Operation ID="OP_01">
        <Description>Operation 1</Description>
        <Phase ID="PREP_FEED">
          <Description>Prep Feed 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="EXTRACT">
          <Description>Extract 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="STRIP">
          <Description>Strip 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="PURIFY">
          <Description>Purify 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="INHIBIT">
          <Description>Inhibit 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="STORE">
          <Description>Store 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.)

---

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