Basicities of Strong Bases in Water: A Computational Study

Kaupmees, Karl; Trummal, Aleksander; Leito, Ivo

doi:10.5562/cca2472

Cited by 95 publications

(76 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recommended p K aH values from ref (in water) or ref (in MeCN). Most of these values are not experimental but obtained by combining information from experiments, computations and/or correlation analysis.…”

Section: Methodsmentioning

confidence: 99%

On the Basicity of Organic Bases in Different Media

et al. 2019

Self Cite

View full text Add to dashboard Cite

The basicities of simple organic bases – aliphatic and aromatic amines, amidines, phosphazenes, as well as saturated and unsaturated nitrogen heterocycles – are examined in acetonitrile, dimethyl sulfoxide, tetrahydrofuran, water and the gas phase. The basicities (pKaH values) of conjugate acids of a large variety of bases in these media are presented and discussed. Equations employing easily usable structural descriptors have been derived for approximately converting basicities from acetonitrile to other solvents. Recommendations are given on their practical use and a number of pKaH values that are experimentally unavailable are estimated from these relationships. An important part of the minireview is a large compilation of pKaH and GB values of the compounds in solvents and the gas phase, respectively, as well as the revised basicity scale in acetonitrile, now containing more than 270 pKaH values.

show abstract

Section: Methodsmentioning

confidence: 99%

On the Basicity of Organic Bases in Different Media

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…between 0.19 and 0.50 wt%) chosen among five different guanidine derivatives with different basicities [37][38][39] (see Table 1 in supporting information). At 60 °C, the NCO conversion curves obtained (x NCO vs. time) are represented in Figure 1.…”

Section: New Guanidine Derivatives As Catalystsmentioning

confidence: 99%

Novel nucleophilic/basic and acidic organocatalysts for reaction between poorly reactive diisocyanate and diols

Belmokaddem

Dagonneau

Lhomme

et al. 2016

Designed Monomers and Polymers

View full text Add to dashboard Cite

International audienceOriginal basic or acidic organic compounds derived from guanidine or phenyl phosphonic acid were specifically designed and tested as new catalysts for the bulk synthesis of polyurethane prepolymers from a precursor system with particularly low reactivity (secondary alcohol + aliphatic isocyanate at low temperature). Both families showed interesting catalytic activities at 60-80 degrees C, but must nevertheless be used in much higher amounts (1mol%, i.e. between 0.15 and 0.50wt%) than traditional metal-based catalysts. The efficiency of guanidine derivatives seems to be related to their nucleophilicity, whereas that of phosphonic acid derivatives depends on their acidity. However, the solubility of the considered species in the reactive medium also plays a major role. The water/alcohol selectivity of the catalysts, especially at room temperature, was then examined as an additional criterion. Guanidines are not selective and favor the reaction of isocyanate groups with water as much as that with alcohols. Phenyl phosphonic acid derivatives are more selective, and particularly pentafluorophenyl phosphonic acid displays a remarkable catalytic activity together with an acceptable selectivity and could represent an interesting and safer alternative to toxic tin and mercury derivatives for many industrial polyurethanes

show abstract

“…The target product (i.e., 2f ) could only be detected in the reaction mixture when a rather strong base such as DBN (p K a = 12.7), TBD (p K a = 15.2), or DBU (p K a = 12.513) was used as the catalyst. The use of DBU, even in small quantities, resulted in the formation of the product (i.e., 2f ) in low yield (40 %), although the process proceeded very quickly.…”

Section: Resultsmentioning

confidence: 99%