Isophthalic dihydrazide

Wrasidlo 79) fabricated semipermeable poly(N-amide)imide (26) membrane from 3,3, 4,4 -benzophenonetetracarboxylic dianhydride (27) and isophthalic dihydrazide (28). The membrane with 28 i thickness had a water flux of 11401/m2 day-2000 A and salt rejection of 99.95%, while a 39.8% acetylated cellulose acetate membrane with 16 ji thickness had values of 118 1/m2 day and 99.35%. 

Di(chlorocarbonyl)pyrazine with isophthalic dihydrazide in A -methyl-pyrrolidinone gave the polyhydrazide (1427). 

The 2,2 -(l,3-phenylene)bis[5-(4-fluorophenyl)-13,4-oxadiazole] (3) was prepared as depicted in Scheme 2 and as follows To a 1 L round bottom flask was added 50.0 g (0.258 mol) of dimethyl isophthalate, 50.0 g (1.0 mol) of hydrazine hydrate and 500 mL of methanol. The mixture was heated at reflux for 4 hours, allowed to cool to room temperature, and stirred for an additional 20 hours. The mixture was filtered, washed with water and dried affording 42 g (84% yield) of isophthalic dihydrazide. In a 250 mL round bottom flask containing 11.0 g (0.0565 mol) of isophthalic dihydrazide and 100 mL of pyridine was added 18.6 g (0.117 mol) 4-fluorobenzoyl chloride over about 5 min. The mixture was refluxed under nitrogen with stirring for 45 min. The mixture was allowed to cool, water was added to precipitate the product, and the product was filtered, washed with water, and dried affording 20 g (86% yield) of the difluoro-bis(hydrazide) (2). 

As trunk polymer a polyetherurethane semicarbazide ("R5 325", Fa. Technochemie, Dossenheim, FRG), composed of 4,4 -diisocyanatodiphenylmethane, poly(oxytetra-methylene) and isophthalic acid dihydrazide was used. 

P-1050 - poly(tetramethylene oxide), 1050 g/mole, L-1050 - poly (propylene oxide), 1050 g/mole, or poly(ethylene oxide) (PEO), 1050 g/mole Same as in Table 1 DADB18C6 -diaminodibenzo-18-crown-6, DHIA - isophthalic acid dihydrazide, HSB15C5 - hydrazide of sulfonylbenzo-15-crown-5, DHDPhMSA - diphenylmethane disulfonic acid dihydrazide... 

TSDC studies proved very powerful for characterizing the various mechanisms of molecular mobility in PUs. In order to assist the discussion of the TSDC data in this and the following sections. Figure 3 shows a TSDC thermogram typical of PUs. It has been recorded with a PU based on PTMG (MW 1000 g/mole), MDI and a mixture of dihydrazide of isophthalic acid and l,4-di-N-oxy-2,3-bis-(oxymethyl)-quinoxaline as chain extender [5]. Four dispersions (TSDC peaks) are well discerned in Figure 3 due to unfreezing of... 

---