pKa Data Compiled by R. Williams pKa Values INDEX Inorganic 2 Phenazine 24 Phosphates 3 Pyridine 25 Carboxylic acids 4, 8 Pyrazine 26 Aliphatic 4, 8 Aromatic 7, 8 Quinoline 27 ... (CH2)5CH(COOH)- 1, -- 57 tetrametaphosphate 2.74 77 Provided by the ACS, Organic Division Updated 4/7/2022 Page 3.

2010年6月18日 · To calculate the Isoelectric point of an amino acid or peptide (or protein, if you are daring), you take the pKa of the carboxylic acid (between 2 and 4 usually) and the amine (9-11), add them, and divide by 2 for the case of an amino acid with no side chain that has a …

2017年10月27日 · In short, the stronger the acid, the smaller the pKa value and strong acids have weak conjugate bases. pKa values describe the point where the acid is 50% dissociated (i.e. deprotonated). Below are tables that include determined pKa values for various acids as determined in water, DMSO and in the gas Phase.

pKa Table: Effect of electronegativity and resonance e.g. Na+ Na+ H2SO4-4 HSO4-HNO3-2 NO3-HCCH 25 alkyne H2N-HCC acetylide e.g., sodium acetylide HCCNa+ H-H Hyg rogen H-H ydie.g,soumh 35 H-Na+ HN H H H 9(10) H3N. B utane CH3CH 2CH2 CH2 - B tylcar bn io e.g, hm CH3CH2CH2CH2-H60 H3 B a s i c i t y Li+ CC H H H H 44 alkene. Title: pKa.cdx

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Equilibrium pKa Table (DMSO Solvent and Reference) Nitro X = H 17.21 O2N-CH2-X Me 16.71 Ph 12.29 SPh 11.810 SO2Ph 7.1 6 COPh 7.76 O2N 16.9 2 N X C X = H 31.31 Me 32.55 Ph 21.99 COPh 10.26 C O-N 17.218 CO2 Et 13.1 18

D.H. Ripin, D.A. Evans 19-20 9 13 11 24.5 H2 ~36 *Values <0 for H2O and DMSO, and values >14 for water and >35 for DMSO were extrapolated using various methods. HCCH Substrate SubstrateSubstrate pKa H2O (DMSO) Substrate AMIDES HYDROCARBONS pKa H2OH(DMSO) pKa pKa2O (DMSO) H2O (DMSO) CH4 CH2=CHCH3 PhH …

pKa Values of Selected Compounds • In structures with more than one proton type, proton corresponding to given pKa is in bold. • Values in parentheses are alternate pKa values given by some sources.

H2O HO ROH RO RS H3CCH3 O H3CCH2 O NC CH3 NC CH2 RC CH RC C NH3 H2N R2CCH R2CCH RC H RC 15.7 16–17 Acid pKa Conjugate Base 11 20 25 25 38 44 ~ 48–53 (p. 2 of 2) NH4 H3N OH O 9.2 10 R R OO H H R R OO H 9 (alkanes) (alcohols) ArCH3 40 ArCH2 2 RSH

The pKa measures how tightly a proton is held by a Bronsted acid. A pKa may be a small, negative number, such as -3 or -5. It may be a larger, positive number, such as 30 or 50. The lower the pKa of a Bronsted acid, the more easily it gives up its proton.