Irganox structure

Various LC-PB-MS and LC-APCI-MS comparisons have been reported on polymer additive extracts [540, 563,629,630]. The complementary character of the El and APCI modes was confirmed. Yu et al. [630] compared LC-PB-MS and RPLC-UV-APCI-MS for detection and identification of unknown additives (in the 252 to 696 Da range) in an acetonitrile extract from PP (containing Irganox 1076, Naugard XL-1 and a degradation product, NC-4, 3-(3,5-di-f-butyl-4-hydroxyphenyl) propanoic acid, 7,9-di-f-butyl-l-oxaspiro [4,5] deca-6,9-diene-2,8-dione and octadecanol-1). Comparison was based on El data (identification of chemical structure), APCI (MW information CID spectrum with limited fragmentation) and PDA (210 nm). The components were identified by El and confirmed by APCI- (with better sensitivity and linearity) MS and PDA showed... 

Figure 7.32 shows the identification of an oxidation product of Irganox 1330 by means of APCI-MS. LC-APCI-MS/MS (high-resolution sector field-ion trap hybrid) has also been used for the analysis (elemental composition and structure) of Irganox PS 802 [636]. 

Figures 10 and 11 show the structure of the hindered phenolic antioxidant Irganox 1010 (Ciba) and its negative ion APCI mass spectra, respectively. Separation was achieved under the following LC conditions Column Aqua Cl 8 (Phenomenex) 3 pm, 150x2.00 mm, 15% carbon loading, proprietary end capping. Column Temp 50°C. Injection volume 5 pi.

Figure 23 Chemical structure of Irganox MD1024 (molecular mass 552).

The molecular structure of the polymer additive IRGANOX 1076 with Mr i = 531 is shown in Appendix III. To calculate the IRGANOX/ethanol partition coefficient use Eq. (4-103) and Table 4-8. Two structural increments are considered Wj(p/L> = 180 for ester and Wj(P/L) = 140 for the 2,6-di-tert-butyl-phenol ... 

A hindered phenol commonly used as an antioxidant is 2,6-di-terf-butyl-4-meth-ylphenol (also known as butylated hydroxy toluene or "BHT"). Structures of BHT and other hindered phenol antioxidants are shown in Figure 8.3. Many of these complex structures have lengthy lUPAC names and are frequently called by trade names assigned by manufacturers, e.g., Irganox 1135 from Ciba (now BASF). 

Degradation products of Irganox 1330 have been extracted from irradiated PP samples by refluxing with chloroform for at least 2 h followed by particle-beam LC-MS analysis. The compounds with quinone methide structures, e.g. l,3,5-trimethyl-2,4,6-tris(3, 5, di-tert-butyl-4-hydroxybenzyl)ben-zene were quantified [64]. 

Figure 1. Structure of TMP-NO- radicals, Tinuvin 770, Tinuvin 622, and Irganox 1010.

Scheme 12.8 Structure of Irganox 1010 having the most pronounced antioxidant efSciency...

The response of polyurethanes to thermally activated autoxidation depends upon polymer structure. In general, polyurethane degradation by this mechanism is suppressed by the addition of antioxidant to the polymer. Ultraviolet initiated autoxidation is suppressed by a suitable screen (e.g. carbon black, titanium dioxide) or a combination of antioxidant and ultraviolet absorber. Irganox 1010 and Tinuvin P (Ciba-Geigy) are particularly suitable antioxidant and ultraviolet absorbers, respectively, for polyurethanes. Polyurethane structures with enhanced resistance to ultraviolet initiated autoxidation may be possible. 

Pentaerythritol tetrakis[3-(3 ,5 -di-tert-butyl-4 -hydroxyphenyl)pro-pionate] of Irganox 1010, Evemox 10, Songnox Chinox 1010 and 1010 trademarks was used as a stabilizer. Structural formula is shown in Fig. 17.1. 

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