Mehmet Karakaplan

SOLVENT EXTRACTION OF BORON WITH l,2-DIHYDROXY-4-OXADODECANE (DHD) IN n-AMYL ALCOHOL

ABSTRACT In the work presented here, l,2-dihidroxy-4-oxadodecane (DHD) was synthesized and used for the solvent extraction of boron. DHD was prepared from glycidol and octanol by thermal epoxide ring opening reaction without using acid or base catalyst. The structure of this new extracting reagent was identified according to its spectroscopic data i.e. 13C NMR, 1H NMR and elemental analysis results. The fixed standard solution of boron (as borax) of 10−4 M was extracted with different volume ratios of DHD and n-amyl alcohol (AA) at different equilibrium pH values. The best extraction result was obtained at high pH values with a mixture of equal volumes of DHD and n-amyl alcohol. The different equilibrium pH values were plotted against the extraction yields (%R) and the pH0·5 value was determined by using this graph. The extraction of boron from aqueous solutions with equal volumes of DHD and various solvents were studied and it was found that petroluem ether, n-amyl alcohol and diisopropyl ether are convi...

Effect of 1,3-Diol Structure on the Distribution of Boron Between CHCl3 and Aqueous Phase

The various new aliphatic 1,3-diols, containing primary, secondary, tertiary, and mixed of these groups, were synthesized and used for the solvent extraction of boron. Diols (8a, 8b, 9, 10a, 10b, 11, 12a, 12b, 13) were prepared from (β-hydroxy carbonyl compounds 1–7. The fixed standard solution of boric acid of 1.00×10−2 M was extracted with 0.1 M and 0.5 M diols at equilibrium pH of 2 and at constant ionic strength (I=0.5). The best extracting reagent was found to be 11, which is a primary–tertiary class of -OH groups and methyl groups as a substituent on the second carbon of 1,3-diol.

Synthesis of C 2-Symmetric Chiral Amino Alcohols: Their Usage as Organocatalysts for Enantioselective Opening of Epoxide Ring

A series of β-amino alcohols derivatives were synthesized from (R)-2-amino-1-butanol and (S)-1,2-propanediol, and they have been used as organocatalaysts in the racemic ring opening of epoxide in good yields with high enantiomeric excess (up to 97%).

The Solvent Extraction of Boron with Synthesized Aliphatic 1,3‐Diols: Stripping and Extraction Behavior of Boron by 2,2,5‐Trimethyl‐1,3‐hexanediol

Abstract A variety of aliphatic 1,3‐diols (4a–c, 5a–c, 6a–c) was synthesized from β‐hydroxy carbonyl compounds (1–3) for potential use in the solvent extraction of boron. Primary‐secondary and primary‐tertiary alcohol structures of 1,3‐diols substituted with isopropyl, isobutyl, and isopentyl groups have been demonstrated to be very efficient for the solvent extraction of boric acid from aqueous solutions. The extraction ability of 2,2,5‐trimethyl‐1,3‐hexanediol (5b) was investigated as a function of 5b concentration, solution pH, solvent properties, and stripping conditions. Extraction efficiency increased with increasing concentration of 5b, and the best extraction of boron (96.8%) was found to be at an equilibrium pH of 2 with 0.5 M of 5b. Chloroform, toluene, chlorobenzene, 2‐octanol, and n‐amyl alcohol were found to be suitable solvents for the solvent extraction of boron. The boron complex can be recovered from the organic phase by treatment with an aqueous solution of sodium hydroxide. The highest ratio (96.7%) of boron was recovered by 0.1 M of sodium hydroxide solution.

A practical synthesis of chiral 3-aryloxy-1,2-propanediols

Chiral 3-aryloxy-1,2-propanediols (1–5) of >96 % ee were obtained in high yield by the nucleophilic addition of substituted phenols to chiral glycidol in the presence of piperidine hydrochloride as catalyst.

Complexation and transport of amino acid esters and their salts with synthesised chiral novel aza crown ether derivatives

The syntheses of four aza-15-crown-5 ethers bearing phenyl and phenoxymethyl moieties attached to a stereogenic centre on the crown ring were achieved. Macrocycles have exhibited strong binding ability (Ka = 5364–12,969 M− 1) and modest enantiomeric discrimination towards the enantiomers of amino acid methyl ester salts by UV titration method in CHCl3 at 25°C. Computer modelling results supported experimental data providing a detailed understanding of the molecular recognition mode between hosts and guests and the likely binding sites involved. Macrocycles were used for chiral discrimination of amino acids in their zwitterionic forms or as potassium and sodium salts in transport experiments across a bulk chloroform membrane with satisfactory selectivity.

Synthesis of new lariat cyclicdiamides and their metal complexes

Three new lariat dilactam host molecules were prepared by the reaction of triethyleneglycol dicarboxylic acid dichloride withN,N′-disubstitutèd-4,7-dioxa-1,10-diazadecane precursors. The amide nitrogen pivot of such compounds are substituted with the benzyl, octyl and dodecyl groups. The complexing ability of these dilactams is displayed with a series of metal complexes of Na+, K+, Ca2+, Sr2+, Pb2+ and Ag+ ions. The structures determined are consistent with the data of1H-NMR,13C-NMR, IR spectra and elemental analyses.