P-Dioxanone
{{DISPLAYTITLE:p-Dioxanone}}
{{Chembox
| Name = p-Dioxanone
| ImageFile = 1,4-Dioxan-2-on.svg
| ImageSize = 100px
| PIN = 1,4-Dioxan-2-one
| OtherNames = para-Dioxanone
|Section1={{Chembox Identifiers
| CASNo = 3041-16-5
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = HLS754O457
| PubChem = 18233
| ChemSpiderID = 17222
| SMILES = C1COC(=O)CO1
| InChI = 1S/C4H6O3/c5-4-3-6-1-2-7-4/h1-3H2
| InChIKey = VPVXHAANQNHFSF-UHFFFAOYSA-N
| StdInChI = 1S/C4H6O3/c5-4-3-6-1-2-7-4/h1-3H2
| StdInChIKey = VPVXHAANQNHFSF-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
| C=4 | H=6 | O=3
| Appearance =
| Density =
| MeltingPt =
| BoilingPt =
| Solubility =
}}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
}}
p-Dioxanone (1,4-dioxan-2-one) is the lactone of 2-(2-hydroxyethoxy)acetic acid. It is a monomer that can undergo ring-opening polymerization to give polydioxanone, a biodegradable implant material.{{cite book |title=Polymeric Biomaterials in Tissue Engineering and Regenerative Medicine |work=Natural and Synthetic Biomedical Polymers |date=20 February 2014 |publisher=Elsevier Science |isbn=978-0-12-396983-5 |editor=Sangamesh Kumbar, Cato Laurencin and Meng Deng}} It is isomeric to trimethylene carbonate (1,3-dioxan-2-one).
Preparation
The common synthetic process for p-dioxanone is continuous gas-phase dehydrogenation of diethylene glycol on a copper or copper chromite catalyst at 280 °C.
:File:1,4-Dioxan-2-on aus DEG.svg
This gives yields of up to 86%. Removal of excess diethylene glycol is crucial to the stability of the product as a monomer.{{Cite patent|country=US|number=5675022|title=Recovery of dioxanone by melt crystallization|pubdate=1995-08-23|gdate=1997-10-07}} Further purification with recrystallization, vacuum distillation,{{Cite patent|country=US|number=2142033|title=Process for the production of 2-p-dioxanone|pubdate=1936-07-01|gdate=1938-10-27}} or melt crystallization allows purities of >99.5% to be achieved.
Properties
Pure p-dioxanone is a white crystalline solid with a melting point of 28 °C.{{Cite journal |last1=Lee |first1=Sang-Won |last2=Kim |first2=Sung-Il |last3=Park |first3=So-Jin |date=2008 |title=Solubility and density of p-dioxanone in organic solvent systems |url=https://koreascience.kr/article/JAKO200807841284700.pdf |journal=J. Korean Oil Chem. Soc. |volume=25 |issue=4 |pages=429–437}}
Uses
The oxidation of p-dioxanone with nitric acid or dinitrogen tetroxide gives diglycolic acid at 75% yield.{{Cite patent|country=US|number=3952054|title=Process for preparing diglycolic acid|gdate=1976-04-20|invent1=Shen|inventor1-first=C.Y.}}
p-Dioxanone can undergo ring-opening polymerization catalyzed by organic compounds of tin, such as tin(II) octoate{{Cite patent|country=US|number=3645941|title=Method of preparing 2-p-dioxanone polymers|gdate=1972-02-09}} or dibutyltin dilaurate, or by basic alkoxides such as aluminium isopropoxide. This affords polydioxanone, a biodegradable, semicrystalline and thermally labile polymer with uses in industry and medicine.{{Cite book |last1=Bezwada |first1=R.S. |url=https://www.worldcat.org/oclc/38861271 |title=Handbook of biodegradable polymers |last2=Jamiolkowski |first2=D.D. |last3=Cooper |first3=K. |date=1997 |publisher=Harwood Academic Publishers |others=A. J. Domb, Joseph Kost, David M. Wiseman |isbn=90-5702-153-6 |location=Australia |pages=29–61 |chapter=Poly(p-dioxane) and its copolymers |oclc=38861271}} Depolymerization back to the monomer is triggered at 100 °C.
