TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The steric property us estimated by ligand cone angle and the triorganophosphine has a ligand cone angle greater than 130 degrees. The electronic property is measured by pKa and the triorganophosphine ligand has a pKa of less than 8.3. The reaction temperature is greater than 45-95 degrees C. The total pressure is greater than 300 - 5000 psig. The reaction process involves hydroformylation, hydroacylation, hydroesterification, carbonylation or hydrocyanation. The rate of ligand usage is less than 2 (preferably less than 0.1) g ligand per liter reaction fluid per day. The reaction process involves contacting 4-60C polyunsaturated olefin with carbon monoxide, optionally in presence of hydrogen, water or alcohol to form as a product, by-product or intermediate product an alpha,beta-unsaturated aldehyde, ketone, ester or acid. The carbonylation reaction is carried in presence of triorganophosphine ligand having a cone angle greater than 135 degrees C and/or pKa of less than 8.3; and/or to a polyunsaturated olefin conversion greater than 80 wt.% and less than 95 wt.% or at greater than 45 degrees C and less than 95 degrees C and/or at greater than 300 psig and less than 5000 psig. The reversion process is conducted at greater than 50 degrees C - less than 150 degrees C. The phosphonium ion ligand degradation product comprises an adduct of a triorganophosphine ligand and 2-pentenal.Preferred Components: The triorganophosphine ligand is selected from tri-isopropylphosphine, tri-isobutylphosphine, tri-tert-butylphosphine, tricyclohexylphosphine, cyclohexyldi-n-butylphosphine, tri-(ortho-methylphenyl)-phosphine, tri-n-butylphosphine, tri-n-octylphosphine, dimethylphenylphosphine, methyldiphenylphosphine, triphenylphosphine and/or their sulfonated salts. The polyunsaturated olefin is 4-60C polyene selected from butadiene, pentadienes, hexadienes, heptadienes, octadienes, dicyclopentadiene, hexatrienes, octatrienes, cyclooctadiene, 2,4-pentadienoic acid, 2,4-hexadienoic acid (sorbic), 2,4-decadienoic acid, 2,4-dodecadienoic acid, cis-9,cis-12-octadecadienoic acid (linoleic), trans-9,trans-12-octadecadienoci acid (linolelaidic), 5,6-octadecadienoic acid (laballenic), 5,13-docosadienoic acid, 6,10,14-hexadecatrienoic acid (hiragonic), cis-9,cis-12,cis-15-octadecatrienoic acid (linolenic), cis-9,trans-11,trans-13-octadecatrienoic acid (alpha-eleosteric), trans-9,trans-11,trans-13-octadecatrienoic acid (beta-eleosteric), mono- to tri-glycerol ester and their 1-8C alkyl esters. The conjugated functionalities olefin is of formula (I).R1-C(R3)=C(R2)(X). (I)X = formyl, keto, ester, acid or nitrile; andR1 - R3 = H or 1-6C monovalent hydrocarbon.At least one of R1 - R3 is a monovalent hydrocarbon.The inert gas is selected from nitrogen, helium, argon, methane, carbon monoxide, and/or steam. The synthesis gas CO/H2 comprises a molar ratio of 10:1 - 1:10. EXAMPLE - 2-Pentenal (50 mmols) was subjected to hydrocarbonylation using triisobutylphosphine under the following conditions: 70 degrees C and 300 psig carbon monoxide, 600 psig hydrogen, 1570 part per million (ppm) Rh, 4.6 mol ligand/mol Rh, and 40 wt.% initial 2-pentenal in 1-butanol solvent, for 3 hours. During the course of reaction 2-pentenal was hydrogenated to valeraldehyde and then to pentanol. After the reaction was completed, the percentage of ligand degradation was found to be 0.3%.