A Spectroscopic Method for Hydroxyl Value Determination of Polyols

Chalasani, Siva Rama Krishna; Dewasthale, Sudhanwa; Hablot, Elodie; Shi, Xiangke; Graiver, Daniel; Narayan, Ramáni

doi:10.1007/s11746-013-2334-9

Cited by 11 publications

(12 citation statements)

References 15 publications

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“…The hydroxyl value (OHV) is defined as the number of milligrams KOH equivalent to the hydroxyl groups found in one gram of the sample and is expressed in mg of KOH/g (Srk et al, 2013). In olive oil, DGs contain the most hydroxyl groups.…”

Section: Adulteration Of Evoo With Roomentioning

confidence: 99%

Comparison of 19F and 1H NMR spectroscopy with conventional methods for the detection of extra virgin olive oil adulteration

Jiang

Chen

et al. 2018

Grasas y Aceites

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This paper reports the comparison of determination methods for extra virgin olive oil (EVOO) adulteration with two kinds of oils, refined olive oil (ROO) and soybean oil by 19FNMR, 1H NMR and chemical titration. The determination of adulteration of EVOO with ROO by 19F NMR was comparable to the conventional method. The contents of oleic, linoleic and linolenic acids of different oil samples can be determined by both 1H NMR and GC-MS. The results obtained from the two methods showed little differences. The adulteration of EVOO with soybean oil is detected by 1H NMR, although the limit of detection of the adulteration level is not less than 4.5%. The research demonstrates that 19F NMR can be a fast and convenient method to detect EVOO if it is adulterated with ROO and 1H NMR can be a fast and convenient method to detect EVOO if it is adulterated with seed oils.

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Section: Adulteration Of Evoo With Roomentioning

confidence: 99%

Comparison of 19F and 1H NMR spectroscopy with conventional methods for the detection of extra virgin olive oil adulteration

Jiang

Chen

et al. 2018

Grasas y Aceites

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“…In addition, the zero-regression equations obtained when the same data is forced through the origin are given in Eqs. (10) and (11). The zero-regression equations facilitate a direct comparison of slopes and each is well within 1% of the ideal slope of 1.0.…”

Section: Analysis Of Pure Alcoholsmentioning

confidence: 75%

A single‐sample method to determine the hydroxyl values of polyols using mid‐FTIR spectroscopy

Tavassoli-Kafrani

Curtis

Voort

2014

Euro J Lipid Sci & Tech

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A single‐sample Fourier transform infrared (FTIR) method suitable for automation was developed to determine the hydroxyl value (OHV) of lipid‐based polyols. It is a modification of the original split‐sample FTIR method using the reaction of p‐toluenesulfonyl isocyanate (TSI) with OH groups and measures the carbamate band formed in the differential spectrum before and after the reaction. In the new method, the TSI‐isocyanate absorption is measured before and after the reaction, the area change being proportional to the OHV of the sample, but is sensitive to moisture. Moisture compensation is achieved by monitoring the CO2 produced by the water‐TSI reaction and correcting for its additional contribution to isocyanate loss. The method was validated by assessing polyol mixtures containing added water, comparing the results to those from the moisture independent split‐sample FTIR method. The single‐sample FTIR procedure had similar accuracy and reproducibility as the split‐sample method when CO2 moisture compensation was implemented. The procedure was not affected by carboxylic acids but can be affected by the presence of amines. The advantage of the new OHV FTIR method is that it requires only a single sample to be prepared and analyzed, making it amenable to automation as well as reducing sample preparation time, solvent, and reagent use. Practical applications: This paper provides an automatable, rapid, and accurate FTIR‐based method for determination of hydroxyl value of polyols, which is a critical parameter of polyols and polyurethane production. The method can be employed by commercial laboratories and researchers working in this area for quality control and to facilitate improvement and development of new products. An FTIR method is described to measure hydroxyl values of polyols using the reaction with isocyanate employed in other methods. The new approach is suitable for automation and moisture compensation is achieved in the same experiment by measuring CO2 produced. Method validation indicates that the method is accurate compared to theoretical values.

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“…(13), one can compare the predicted OHV to the theoretically expected values as determined by Eq. (8). Figure 6 presents a plot of experimentally determined OHV against the calculated theoretical OHV for a series of pure alcohols and gravimetrically prepared mixtures of those alcohols.…”

Section: General Conceptsmentioning

confidence: 99%

“…The FTIR method is not affected by moisture and avoids the requirement to correct for carboxylic acid acidity or amine basicity. Although other FTIR-based methods for the determination of OHV exist [2][3][4]8] these all depend on calibration against a primary reference method and all use sophisticated chemometrics to obtain a calibration, other than the new silylation method [8]. As a result, with the exception of the silylation method, these methods tend to be limited to a restricted universe of samples and are problematic for the general analysis of polyols.…”

Section: Variables Affecting Quantitationmentioning

confidence: 99%

“…Furthermore, although turnkey, pre-calibrated near-IR instrumentation does exist for polyol analysis [7], it still usually requires tuning of the calibration to suit the sample type being analyzed, with bio-polyols not generally being represented. Just prior to submission of this manuscript a new ATR method for determination of OHV based on polyol OH silylation was published [8] which uses a stoichiometric reaction to replace the problematic OH signal with a methyl silyl ether. The latter has a far stronger IR signal which is both more readily measured and less prone to hydrogen bonding effects, but requires a 1 h reaction at 60°C.…”

Section: Introductionmentioning

confidence: 99%

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A Primary Method for the Determination of Hydroxyl Value of Polyols by Fourier Transform Mid‐Infrared Spectroscopy

Tavassoli-Kafrani¹,

Curtis²,

Voort³

2014

J Americ Oil Chem Soc

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A primary Fourier transform infrared (FTIR) method was developed to determine the hydroxyl value (OHV) of polyols produced from edible oils. The method is a modification of American Society for Testing and Materials 1899-08, using toluene as the solvent to dissolve the sample and to carry the reactive reagent p-toluenesulfonyl isocyanate (TSI). TSI reacts with OH groups to produce a carbamate, a functional group that can be measured spectrally between *1780 and 1690 cm -1 in the differential spectrum that is obtained from spectra collected before and after the reaction. Commercially available 1-nonanol, which has a defined OHV, is used to develop a calibration. The OHV for a variety of 1°and 2°alcohols, as well as petrochemical and lipidbased polyols, were then measured to evaluate the performance of the method and to assess the effects of moisture on the results. The FTIR OHV were in accord with the results obtained by AOCS method Cd 13-60 and were demonstrated to be unaffected by the presence of moisture in the sample. The new TSI-FTIR method is simpler, much faster (*10 min), and more reproducible and accurate than the AOCS OHV titrimetric methods and is not affected by carboxylic acids, amines or moisture.

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A Spectroscopic Method for Hydroxyl Value Determination of Polyols

Cited by 11 publications

References 15 publications

Comparison of <sup>19</sup>F and <sup>1</sup>H NMR spectroscopy with conventional methods for the detection of extra virgin olive oil adulteration

Comparison of <sup>19</sup>F and <sup>1</sup>H NMR spectroscopy with conventional methods for the detection of extra virgin olive oil adulteration

A single‐sample method to determine the hydroxyl values of polyols using mid‐FTIR spectroscopy

A Primary Method for the Determination of Hydroxyl Value of Polyols by Fourier Transform Mid‐Infrared Spectroscopy

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