Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite

Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite
Names
	Preferred IUPAC name 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane
	Other names Trade names; Irgafos 126 (BASF); ADK Stab PEP 24 (Adeka); Ultranox 626 (SI Group);
Identifiers
CAS Number	27676-62-6;
3D model (JSmol)	Interactive image;
ChemSpider	84048;
ECHA InfoCard	100.043.578
EC Number	248-597-9;
PubChem CID	93101;
UNII	GV29P0K7AC;
CompTox Dashboard (EPA)	DTXSID2027911 ;
	InChI InChI=1S/C33H50O6P2/c1-29(2,3)23-13-15-27(25(17-23)31(7,8)9)38-40-34-19-33(20-35-40)21-36-41(37-22-33)39-28-16-14-24(30(4,5)6)18-26(28)32(10,11)12/h13-18H,19-22H2,1-12H3 Key: InChIKey=AIBRSVLEQRWAEG-UHFFFAOYSA-N;
	SMILES O(P1OCC2(COP(OC3=C(C(C)(C)C)C=C(C(C)(C)C)C=C3)OC2)CO1)C4=C(C(C)(C)C)C=C(C(C)(C)C)C=C4;
Properties
Chemical formula	C33H50O6P2
Molar mass	604.705 g·mol−1
Appearance	White solid
Density	1.166 at 20°C
Melting point	172–179 °C (342–354 °F; 445–452 K)
Boiling point	311 °C (592 °F; 584 K)
Solubility in water	93.0 µg/L at 25°C
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H410
Precautionary statements	P261, P264, P264+P265, P271, P273, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P391, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite is an organophosphite used as a polymer stabilizer in plastics. Like other phosphite antioxidants it primarily acts to remove hydroperoxides and is typically used in combination with hindered phenolic antioxidants such as pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate).

Synthesis

It is formed by a reaction between phosphorous trichloride, pentaerythritol and 2,4-di-tert-butylphenol. The poor solubility of pentererythritol can be an issue and non-nuncleophilic amines are often used to promote the reaction.^[1]

Properties and applications

Compared to tris(2,4-di-tert-butylphenyl)phosphite (a common phosphite antioxidant) it has higher activity but lower stability against hydrolysis. Trace levels of amine bases are often added to commercial material to slow hydrolysis and increase storage life.^[2] It's crystal structure has been determined.^[3] It is comparable with a wide range of plastics including polyolefins, engineering plastics and polyurethane fibers. It is an approved food contact material in the US.^[4]

References

^ Zhu, Yuliang; Liu, Xinyue; Tang, Ying; Xu, Kexin; Tang, Xin; Zhu, Longzhi; Xiong, Biquan (13 November 2024). "Recent Advances in the Synthesis of Commercially Available Phosphite Antioxidants". ChemistryOpen: e202400135. doi:10.1002/open.202400135. PMID 39538976.
^ Papanastasiou, M.; McMahon, A.W.; Allen, N.S.; Doyle, A.M.; Johnson, B.J.; Keck-Antoine, K. (November 2006). "The hydrolysis mechanism of bis(2,4-di-tert-butyl)pentaerythritol diphosphite (Alkanox P24): An atmospheric pressure photoionisation mass spectrometric study". Polymer Degradation and Stability. 91 (11): 2675–2682. doi:10.1016/j.polymdegradstab.2006.04.023.
^ Barren, J. P.; Bryant, G. L.; Garbauskas, M. F.; Mahood, J. A. (15 August 1995). "Bis(2,4-di-tert-butylphenyl) Pentaerythritol Diphosphite". Acta Crystallographica Section C Crystal Structure Communications. 51 (8): 1636–1639. Bibcode:1995AcCrC..51.1636B. doi:10.1107/S0108270195000965.
^ "FDA broadens food contact approval for SI Group's Ultranox 626 antioxidant". Additives for Polymers. 2019 (9): 4. September 2019. doi:10.1016/S0306-3747(19)30174-5.

[1] Zhu, Yuliang; Liu, Xinyue; Tang, Ying; Xu, Kexin; Tang, Xin; Zhu, Longzhi; Xiong, Biquan (13 November 2024). "Recent Advances in the Synthesis of Commercially Available Phosphite Antioxidants". ChemistryOpen: e202400135. doi:10.1002/open.202400135. PMID 39538976.

[2] Papanastasiou, M.; McMahon, A.W.; Allen, N.S.; Doyle, A.M.; Johnson, B.J.; Keck-Antoine, K. (November 2006). "The hydrolysis mechanism of bis(2,4-di-tert-butyl)pentaerythritol diphosphite (Alkanox P24): An atmospheric pressure photoionisation mass spectrometric study". Polymer Degradation and Stability. 91 (11): 2675–2682. doi:10.1016/j.polymdegradstab.2006.04.023.

[3] Barren, J. P.; Bryant, G. L.; Garbauskas, M. F.; Mahood, J. A. (15 August 1995). "Bis(2,4-di-tert-butylphenyl) Pentaerythritol Diphosphite". Acta Crystallographica Section C Crystal Structure Communications. 51 (8): 1636–1639. Bibcode:1995AcCrC..51.1636B. doi:10.1107/S0108270195000965.

[4] "FDA broadens food contact approval for SI Group's Ultranox 626 antioxidant". Additives for Polymers. 2019 (9): 4. September 2019. doi:10.1016/S0306-3747(19)30174-5.

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