Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: winiany

Sortuj według:

Ogranicz wyniki do:

Electrodeposition of silver from nitrate-tartrate solutions

Rudnik E.

Metallurgy and Foundry Engineering

2018

Vol. 44, no. 2

81--89

The electrodeposition of silver from AgNO3 solutions with the addition of L-tartaric acid was investigated. The cathodic reaction was accompanied by low electrode polarization and run under activation control for AgNO3 concentrations of above 70 mM. Tartaric acid only slightly shifted the polarization curves towards more electronegative potentials (by approx. 50 mV), but it did not change the rate-determining step. The activation control of the process resulted in the formation of rough and coherent deposits, while the mixed or diffusion control of the process promoted the formation of dendritic-like structures and spongy deposits.

Przeprowadzono badania katodowego osadzania srebra z roztworów AgNO3 zawierających L-kwas winowy. Reakcji katodowej towarzyszy mała polaryzacja elektrody, a redukcja biegnie w zakresie kontroli aktywacyjnej dla stężeń AgNO3 powyżej 70 mM. Dodatek kwasu winowego w niewielkim stopniu przesuwa krzywe polaryzacyjne w kierunku bardziej ujemnych potencjałów (o ok. 50 mV), nie zmieniając jednak etapu powolnego reakcji katodowej. W zakresie kontroli aktywacyjnej tworzą się szorstkie i zwarte warstwy srebra, natomiast zakres kontroli mieszanej lub stężeniowej sprzyja tworzeniu się struktur dendrytopodobnych lub gąbczastych.

Kwas winowy i jego pochodne we współczesnej chemii organicznej

Grajewski J.

Wiadomości Chemiczne

2013

[Z] 67, 5-6

495--519

The tartaric acid and its salts have been present in chemistry for almost 350 years, since Pierre Seignette isolated Rochelle salt in 1675. Since that time tartaric acid and its derivatives have been often used in chemistry due to their accessibility, enantiopurity, relatively low cost and presence of different functional groups which easily allow to modify the molecule. Many tartaric acid derivatives serve as catalysts in important stereoselective transformations such as Sharpless asymmetric epoxidation or asymmetric Rousch aryloboronation. In many others reactions tartaric acid have been employed as a chiral building block for natural products synthesis, highly functionalized molecules or ligand design such as well known TADDOL or its analogues. Its polar functional groups allow to form crystals with amines and aminoalcohols what is widely used for their enantiopurification and resolution. The relatively new subdiscipline is the use of tartaric acid in chiral recognition and chiral discrimination in nanochemistry and enantioselective chromatography. The other, recent applications of tartaric acid include functionalization of metal layers, antibacterial and antifungal activity among many others. The significance of tartaric acid is evident – since 2000, words “tartaric acid” or “tartrates” can be found in databases over four thousand times. Taking that into account this short review is concentrated on selected applications of tartaric acid and its derivatives in organic chemistry in recent several years.