Rigid Polyurethane Foam Based on Modified Soybean Oil

Two bio-based polyols (Polyol-r and Polyol-t) were synthesized from commercially available epoxidized soybean oil (ESBO). Polyol-r was obtained from ring opening of ESBO in the presence of fluoboric acid, while Polyol-t from a transesterification of Polyol-r with glycerol through a litharge catalyst. A rigid polyurethane foam was prepared by mixed polyols (Polyol-t and commercial 635 polyether polyol) with 4,4'-methylene-bis (phenyl isocyanate). The hydroxyl value of Polyol-t was higher than that of Polyol-r, which was also backed up by Fourier transform infrared spectrometry. Scanning electron microscope examination revealed that the foam has closed cells. The test of performances of the foam shows that it possesses an excellent dimension stability and compressive strength.

Azo pigments and their intermediates. A reinvestigation of the tetrazotization of 1,4-diaminoanthraquinone

The azotization of 1,4-diaminoanthraquinone (1) by n-amyl nitrite in glacial acetic was reinvestigated. The structure of a red-brown precipitate, which was previously identified as anthraquinone-1,4-tetrazonium dichloride (3) by Schaarschmidt, was found to be incorrect. In this work, we have identified the red-brown solid as 4-aminoanthraquinone-1-diazonium chloride (2), a diazotized product of 1. The yield of 2 was 80%. The tetrazonium dichloride 3 was actually formed in minute quantity and is soluble in acetic acid. The tetrazonium product of 1 can be isolated as tetrafluoroborate salt 4 in 3.4% yield by adding fluoboric acid into the acetic acid solution. The structure 4 was confirmed by IR and cross-polarization magic angle spinning13C NMR spectroscopy. Further investigations showed that 1 can be quantitatively tetrazotized by nitrosylsulfuric acid in 78% sulfuric acid. The tetrazonium product was isolated as 4 in 74% yield. Key words: 1,4-diaminoanthraquinone, diazotization, tetrazotization, azo pigments.