Retention characteristics of aliphatic compounds on cellulose acetates as a stationary phase with an aqueous mobile phase

Summary Cellulose and cellulose mono-, di-, and triacetate were used as stationary phases for liquid chromatography with water as a mobile phase, and the retention behavior of alcohols, ethers, ketones, and chlorides was examined. For cellulose acetate columns, the logarithm of the specific retention volume, (logV _g ^* ), correlated linearly with the logarithm of partition coefficient between 1-octanol and water (log K_o/w), for each homologous group, but all solutes were unretained on cellulose columns. With the exception of chlorides, the intercept values of the log V _g ^* –log K_o/w regression lines increased significantly with increase of acetyl content of cellulose acetates, but the slopes of the regression lines changed little. This suggests that hydrophobic interaction between the acetyl groups of cellulose acetates and the alkyl chains of the solutes is the dominant factor in the retention.The capacity factors for 1-alcohols with cellulos diacetate column indicated a maximum at a column temperature of about 40°C. This unique retention behavior was assumed to be caused by small structural change of the cellulose acetate polymer, because this temperature effect on the retention corresponded with effects observed by differential scanning calorimetry (DSC).     

Microwave spectra, molecular structure and theoretical calculation of two isotopic species of acetyl isocyanate CD3C(O)NCO and CH3C(O)NCO

The microwave spectra of two isotopic species of acetyl isocyanate, ¹³CH₃C(O)NCO and CD₃C(O)NCO, were observed in order to determine the r_o structure and confirmation of the molecular conformation. These isotopic species were prepared by reacting acetyl-2-¹³C-chloride or acetyl-d₃ chloride with sliver cyanate. The rotational spectra of A-level in 26.5-60.0 GHz region have been observed by Stark-modulated microwave spectrometer. Some absorption lines in E-level were observed in ¹³CH₃C(O)NCO. The rotational constants in the ground vibrational state were determined to be A = 10654.8(18), B = 2177.32(2), and C = 1827.65(2) MHz for ¹³CH₃C(O)NCO, and A = 9713.90(6), B = 2042.04(2), and C = 1722.78(2) MHz for CD₃C(O)NCO, respectively. The values of ΔI (= I_c − I_a − I_b) of the ¹³C species (−3.024(13) uŲ) and the d₃ species (−6.163(3) uŲ) indicate that the molecule has C_s symmetry. The r_s coordinates of the carbon atom in the methyl group were determined to be |a| = 2.183(3), |b| = 0.706(9), and |c| = 0.080(87) Å. The determined coordinates were in agreement with those calculated for the cis form, in which the carbonyl group is eclipsed by the NCO group. The six structural parameters of the cis form were adjusted by fitting to the observed rotational constants. The observed rotational constants of the cis form were in better agreement with those calculated using the QCISD/6-31G (d, p) level rather than those calculated using the MP2/6-31G (d, p) level. The barrier of internal rotation of the methyl group was determined as 4.283(16) kJ mol⁻¹ in ¹³CH₃C(O)NCO. The structural tendencies and the relationship between ∠RNC and ¹⁴N quadrupole coupling constants (χ_cc) were discussed.     

Preparation and Characterization of a Bipolar Membrane Modified by Copper Phthalocyanine 16-Carboxylic Acid and Acetyl Ferrocene

A bipolar membrane (BPM) of carboxymethyl cellulose (CMC) and chitosan (CS) with superior performance was prepared based on the macromolecules containing metal elements. A carboxymethyl cellulose cation layer was modified by copper phthalocyanine 16-carboxylic acid (CuPc(COOH)₁₆) to improve its ion exchange capacity as well as cation transfer rate and promote water splitting at the intermediate layer. Chitosan was crosslinked with acetyl ferrocene to prepare the anion layer. A casting method was used to prepare the BPM which showed excellent physical and chemical properties after modification. To improve the compatibility of the anion-exchange layer and cation-exchange layer, polyethylene glycol (PEG) was blended with both the CMC and CS. Scanning electron microscopy (SEM) images illustrated a structure that consisted of an anion layer and a cation layer that were closely combined with each other. The swelling results implied a proper hydrophilic performance and good shape stability in an alkali solution ([OH^?]≤10 mol·L^?1) of the BPM. After modification, the BPM with the metal elements exhibited good thermal stability, as shown by the thermogravimetry (TG) results. Compared with the BPM that was unmodified, both the AC impedance and the working voltage were decreased sharply. Furthermore, the modified BPM exhibited higher ion penetrability which is beneficial for its wide application.     

FeCl3/pyridine: dual-activation in opening of epoxide with carboxylic acid under solvent free condition

Inexpensive, non-toxic, and readily available catalyst system FeCl₃/pyridine was found to be highly efficient for the opening of a wide variety of epoxides with carboxylic acid under solvent free conditions.     

A Novel Method for the Synthesis of Acetyl Phosphate

A facile method for the synthesis of acetyl phosphate by a reaction of 2-hydroxypropylphosphate with acetic acid is described.     

Deacetylation of Thioacetate using Acetyl Chloride in Methanol

A highly efficient method for the deacetylation of thioacetate is reported under mild acidic conditions employing acetyl chloride in methanol. Some of the major advantages are mild conditions, high efficiency, high yields, and easy operations.     

Efficient AcFc-[FeIII(acac)3] Redox Couple for Non-aqueous Redox Flow Battery at Low Temperature

The temperature dependency of the electrochemical analysis of acetyl ferrocene (AcFc) and iron(III) acetylacetonate ([Fe(acac)₃]) has been investigated for non-aqueous redox flow batteries (NARFBs). AcFc and [Fe(acac)₃] were utilized as catholyte and anolyte species, respectively, in an electrochemical cell with a cell voltage of 1.41 V and Coulombic efficiencies >99% for up to 50 total cycles at room temperature (RT, 25 °C). Experiments with a rotating ring disk electrode (RRDE) indicate that the diffusion coefficient reduces with decreasing temperature from 25 °C to 0 °C, yet the overall storage capacity was higher than that of an aqueous redox flow battery (ARFBs). The electrochemical kinetic rate constant (k₀) of AcFc was found to be greater than that of [Fe(acac)₃]. However, the value of k₀ was not affected by the variable temperature. ¹H NMR investigations reveal that temperature change during battery trials did not occur in any structural modification. The obtained result demonstrates the suitability of this battery at low temperatures.