2 replies to this topic

[norkun]

Hi everyone, in our term project we designed Cumene Production with Q-max process. And we designing this process' pipeline now. So we need benzene, propylene, propane and cumene's pH values for calculated optiumum and safety diameter.

[kkala]

According to my information, pH refers only to aqueous solutions, expressing concentration of H⁺ in logarithmic scale at 25 oC (where (H⁺)*(OH^-)=1E-14 for pure water). It is not valid for organic liquids, like benzene, cumene, propane, propylene.
If transferred organic liquids contain traces of water, this will have a pH value depending on their impurities (e.g. phenol or H3PO4 impurities can create weak acidic pH in the water). But said liquids (involved in the cumene synthesis) are expected to have been completely free of water.
Probably you want to know corrosion properties of said liquids. Concerning propane and propylene, we have assumed carbon steel in several studies; pure benzene does not seem corrosive to carbon steel (Perry, 5th ed -1973, Materials of Construction). Cumene was not found, but it might not be corrosive to carbon steel either, since all said liquids are hydrocarbons. Check of their specs (water content, impurities) might guide to more precise conclusions. If this is not easy, I would assume carbon steel preliminarily.
Note: Sulfur compounds / H2S are possible in heavy petroleum products, probably necessitating annealing of carbon steal pipes. But apparently this is not the case of said pure liquids (synthetic benzene).

Edited by kkala, 24 March 2012 - 11:55 AM.

[burkhae]

What you may be looking for is pKa value for the hydrocarbons mentioned. Check out this website below for more info. It has propane and benzene but not cumene or propylene. But some of the other links may lead you to those pKa values also.
www.chem.wisc.edu/areas/reich/pkatable/index.htm