20.500.12556/RUL-110564 Vpliv kovinskih ionov na zvrsti citronske kisline v odvisnosti od pH Metal ions influence on different citric acid species in relation to pH Pripravila sem raztopino citronske kisline (H4L) v vodi, ter vsakemu delu le- te dodala po eno izbrano zvrst kovinskih kloridov (NaCl, CaCl2, ZnCl2 ali CuCl2). Vsaki od teh raztopin sem nato dodajala raztopino NaOH do nevtralizacije raztopine. Vsem raztopinam je pH sorazmerno enakomerno naraščal do pH = 7. Bistvena razlika je bila pri Cu2+, kjer se je za nevtralizacijo porabila dvojna količina NaOH. Očitne razlike sem opazila pri merjenju prevodnosti, kjer je ob dodajanju močnega elektrolita NaOH prevodnost enakomerno naraščala le pri enovalentnih natrijevih ionih, pri ostalih (torej dvovalentnih) pa so vidna tudi izrazita upadanja prevodnosti. Takšne krivulje se skladajo s predvideno boljšo možnostjo vezave dvovalentnih kovinskih kationov na anion citronske kisline. Te pojave sem primerjala s tremi znanimi bakrovimi spojinami v tem sistemu [Cu2(L)(H2O)2]n, (CN3H6)4[Cu2(L)2](H2O)2 in (CN3H6)[Cu2(OH)(L) (CN3H5)2], katere sem sintetizirala po opisih v virih. Istovetnost teh trdnih spojin sem potrdila z elementno in praškovno rentgensko analizo, ter z IR ponovljivost sintez. A solution of citric acid (H4L) was prepared in water, to a portion of which one selected type of metal chlorides (NaCl, CaCl2, ZnCl2 or CuCl2) was added. To each of these solutions the NaOH solution was added until neutralized. The pH of all solutions rises steadily till pH =7, , with the most obvious difference for Cu2+, for which double amount of NaOH was needed for the neutralization. The most obvious differences were noticed at conductivity measurements, where with a strong electrolyte, namely NaOH was adding, the conductivity steadily rises only for the monovalent sodium ions. On other hand, with the other metal ions (notably divalent) clearly conductivity decreases are seen. These curves are consistent with the anticipated better ability of the divalent metal cations binding to the citric acid anion. These observations were compared to three of the known copper compounds in this system, namely [Cu2(L)(H2O)2]n, (CN3H6)4[Cu2(L)2](H2O)2 and (CN3H6)[Cu2(OH)(L)(CN3H5)2], being synthesized as previously described in resources. The identity of these compounds was confirmed by elemental and powder X-ray analysis, while the IR was applied for the synthesis reproducibility checking. citronska kislina kovinski ioni pH elementna analiza rentgenska praškovna analiza IR spektroskopija citric acid metal ions pH elemental analysis X-ray powder analysis IR spectroscopy true false false Slovenski jezik Angleški jezik Diplomsko delo/naloga 2019-09-17 11:45:07 2019-09-17 11:45:11 2022-08-22 03:44:33 0000-00-00 00:00:00 2019 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 4964 1538435779 Hodzic_Sara_-_Vpliv_kovinskih_ionov_na_zvrsti_citronske_kisline_v_odvisnosti_od_pH.pdf Hodzic_Sara_-_Vpliv_kovinskih_ionov_na_zvrsti_citronske_kisline_v_odvisnosti_od_pH.pdf 1 59924D8D5EC4BDAA6430671D17A221C5 7912afb45a2be0c65b563959bb4a85b55edf62f99979225bf9c9ff028dc4723f 25f26df9-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=122234 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0