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 Values INDEX Inorganic 2 Phenazine 24 Phosphates 3 Pyridine 25 Carboxylic acids 4, 8 Pyrazine 26 Aliphatic 4, 8 Aromatic 7, 8 Quinoline 27 Phenols 9 Quinazoline 27 Alcohols and oxygen acids 10, 11 Quinoxaline 27 Amino Acids 12 Special Nitrogen Compounds 28 Peptides 13 Hydroxylamines 28

Note; The pKa values associated with bases is normally meant to refer to the true pKa's of their conjugate acids; i.e., pKa associated with HO- is 15.7, which is the pKa of H2O. This is often sloppily used by organic chemists, and can lead to confusion, especially with amines.

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 …

In organic chemistry, a methoxy group is the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula R−O−CH3. On a benzene ring, the Hammett equation classifies a methoxy substituent at the para position as an electron-donating group, but as an electron-withdrawing group if at the meta position.

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.

Equilibrium pKa Table (DMSO Solvent and Reference) Hydrocarbons 20.117 21.822 22.522 17.317 Ph 18.019 26.122 Fluorenes X X = H 22.61 Me 22.31 Ph 17.91 tBu 24.421 SiMe3 21.5 26 SiPh3 18.6 26 = Fl-X Et 22.321 iPr 23.221 CO2Me 10.3 1 CN 8.31 OMe 22.15 OPh 19.95 OiPr 21.45 OtBu 21.35 SMe 18.07 SPh 15.55 +NMe3 17.8 33 i-Bu 21.6 Cl 18.9 CH2 tBu 20.3 ...

Approximate pKa chart of the functional groups: values to know 1. Protonated carbonyl pKa = ‐7 Other important pKa’s 2. Protonated alcohol or ether pKa = ‐2 to ‐3 H2 = 35 3.

CH3OH ＞ 1 醇 醇 醇 取代酚的酸性影响因数： 酚羟基的邻、对位上有强吸电子时，酸 性增强，吸电子基越多，酸性越强； 酚羟基的邻、对位上有给电子时，酸性 减弱。 此法主要用于硝基酚和氯代酚的生产。 (3) 碱熔法制备酚. 此法曾是工业制酚的主要方法. f多元醇的命名： ——写出多个羟基所在位置。 HOCH2CHCH3 HOCH2CH2CH2OH OH 1,3-丙二醇 1,2-丙二醇 (2) 酚的命名 酚的俗名： 9.6.2 醚的生成 醇的酸性太弱，不能与卤代烃反应生成 醚。 醇、酚的金属盐与卤代烃作用， …