Zirconium n-propoxide

Description

Zirconium n-propoxide (Zr(OPr)4)

Overview

• Chemical identity: Zirconium tetra-n-propoxide, formula commonly written as Zr(C3H7O)4 or Zr(OPr)4. Because the propoxide group can be linear (n-propoxide) or branched (isopropoxide), you may also see references to Zr(OPr)4 or Zr(OiPr)4, depending on the specific propoxide used.
• Role: A widely used zirconia precursor in sol–gel chemistry and thin-film/ceramic processing. It readily undergoes hydrolysis and condensation to form Zr–O–Zr networks.

Key characteristics

• Appears as a colorless to pale yellow liquid or solution in an alcohol.
• Moisture sensitive and can hydrolyze in air; typically stored under dry, inert conditions.
• Often isolated or used as a solvated or stabilized solution with alcohol (e.g., Zr(OPr)4·nROH).

Preparation

• A common laboratory route is alkoxide exchange from ZrCl4 with sodium propoxide:
  • ZrCl4 + 4 NaOPr → Zr(OPr)4 + 4 NaCl
• Alternative routes include transesterification or hydrolysis of other zirconium alkoxides under controlled conditions. In all cases, water must be carefully controlled to manage hydrolysis and condensation.

Hydrolysis and sol–gel behavior

• In the presence of water, Zr(OPr)4 undergoes hydrolysis:
  • Zr(OPr)4 + x H2O → Zr(OR)4−x(OH)x + x ROH
• The hydrolyzed species condense to form Zr–O–Zr linkages, releasing alcohol (ROH). This leads to network formation and eventually zirconia (ZrO2) upon drying and/or calcination.
• In sol–gel processing, the water amount, acid/base catalyst, and solvent composition are used to control:
  • Hydrolysis rate
  • Degree of condensation
  • Porosity and microstructure of the final oxide
• Typical processing notes:
  • Acid catalysts (e.g., HCl, acetic acid) retard hydrolysis for better control.
  • Alcohol co-solvents help manage precursor stability and viscosity.
  • Partial hydrolysis can yield gels with tunable porosity and film quality.

Handling and safety

• Handling: Work under dry, inert conditions if you want to maximize shelf life. Use appropriate PPE and work in a well-ventilated area.
• Storage: Keep in tightly closed containers, away from moisture and incompatible reagents.
• Safety notes: Corrosive and irritation hazards; reacts with water and air moisture to release alcohol and eventually form oxide networks. Avoid contact with strong oxidizers and heat.

Applications

• Sol–gel derived ZrO2 ceramics and coatings: Films, fibers, and bulk ceramics with controlled porosity and microstructure.
• Catalysis and supported catalysts: Used as a zirconia precursor to prepare active oxide supports.
• Optical and dielectric ceramics: High-rek, high-dielectric-constant materials via carefully engineered sol–gel routes.
• Doping and composite systems: Used in conjunction with dopants to tailor properties.

Quick reference data

• Formula: Zr(C3H7O)4 (or Zr(OPr)4)
• Molecular weight: ≈ 328 g/mol (approximate, depends on exact propoxide isomer)
• Typical state: Moisture-sensitive liquid or solution in an alcohol
• Common preparation route: ZrCl4 + 4 NaOPr → Zr(OPr)4 + 4 NaCl
• Primary reactivity: Hydrolysis and condensation to form Zr–O–Zr networks

Example use: simple sol–gel outline

1. Prepare a dry solution of Zr(OPr)4 in an alcohol (or solvent mixture).
2. Add a controlled amount of water (and sometimes an acid catalyst) to initiate hydrolysis.
3. Allow controlled condensation to build a gel network.
4. Dry and calcine to obtain ZrO2 with the desired microstructure.

If you’d like, I can tailor this to a specific application, such as a step-by-step sol–gel recipe for a dense ZrO2 film, or compare Zr(OPr)4 with other zirconium alkoxides for your process.