ChemWatch is the best source for Material Safety Data Sheets (MSDS) of chemicals held at the University of Canterbury.
The Biofuels Handbook by 
McGraw-Hill Concise Encyclopedia of Science and Technology by 
McGraw-Hill Dictionary of Scientific and Technical Terms by 
McGraw-Hill's Engineering Companion by 
Chemical Engineer's Condensed Encyclopedia of Process Equipment by 
CRC handbook of Chemistry and Physics
A ready-reference book of chemical and physical data
Perry's Standard Tables and Formulae for Chemical Engineers by 
Van Nostrand's Encyclopedia of Chemistry by 
