High Pressure Air Properties

try a search for nitrogen at that T and P, as here. There may be a greater body of work online and once you find it, you can drill down and see if they have data on air.

You can add terms like -abc and +def to fine tune and prune the hits to a smaller number. High performance jet engine makers work at least partly into that regime, temperature wise, but not pressure wise, and they may have tables that do reach your area of interest and they may share them with you if your interest is scholarly and not competitive.

http://www.google.ca/search?hl=en&safe=off&q=%22high+temperature%22+%2B%22high+pressure%22+%2Bnitrogen+%2Bthermodynamic&btnG=Search

http://www.google.ca/search?hl=en&safe=off&q=%22high+temperature%22+%2B%22high+pressure%22+%2Bair+%2Bthermodynamic&btnG=Search

Thank you very much. I shall try the suggested strategy.