Tetrabutylurea, TBU CAS NO: 4559-86-8 TBU is one of most important solvent in the production of Hydrogen Peroxide. Weifang Menjie Chemical Co.,ltd have been produced Tetrabutylurea and 2-ethylanthraquinone from 1993. AppearanceClear LiquidClear Liquid Purity % â?¥99.599ï¼?52 Density (20â??)g/cm30ï¼?877±0.0030ï¼?877 Sulphur PPM â?¤10.9 Water % â?¤0.10.09 Color,APHA â?¤3029 Surface tension (25â??) â?¥ mN/m19.520 Dibutylamine %â?¤0.10.06 Flash point â?? â?¥140142