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

Tavassoli-Kafrani, Mohammad Hossein; Curtis, Jonathan M.; Voort, F.R. van de

doi:10.1007/s11746-014-2451-0

Cited by 15 publications

(19 citation statements)

References 13 publications

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“…Since the regression statistics are not altered significantly by the removal of the intercepts, this confirms that the two FTIR methods, which are in close agreement with each other, also agree well with the theoretical values. Thus for pure alcohols and mixtures thereof, the single-sample FTIR method has similar reproducibility and accuracy as the split-sample FTIR method, which was previously demonstrated to be more accurate and reproducible than AOCS Cd-13-60 [15].…”

Section: Analysis Of Pure Alcoholsmentioning

confidence: 84%

“…In order to evaluate the general performance of the single‐sample FTIR method, a series defined alcohols and mixtures thereof were analyzed for their OHV using both the single‐sample and split‐sample FTIR methods and the results were compared to the theoretical OHVs determined using Eq. for pure alcohols of known structure:

OHV (mg KOH / g) = (nOH / Mw) \times (56100)

where nOH = number of hydroxyl groups in the molecule, Mw = molecular weight (g).…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, amines do react faster with TSI and will result in a loss of isocyanate as per Eq. (15).…”

Section: Carboxylic Acids and Aminesmentioning

confidence: 99%

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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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Section: Analysis Of Pure Alcoholsmentioning

confidence: 84%

OHV (mg KOH / g) = (nOH / Mw) \times (56100)

where nOH = number of hydroxyl groups in the molecule, Mw = molecular weight (g).…”

Section: Methodsmentioning

confidence: 99%

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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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“…The determination of the hydroxyl number was done according to DIN 5 3240‐2 . This method was based on the catalytic acetylation of hydroxyl groups.…”

Section: Methodsmentioning

confidence: 99%

“…The determination of the hydroxyl number was done according to DIN 5 3240-2. [28] This method was based on the catalytic acetylation of hydroxyl groups. After hydrolysis of the intermediate product, the remaining acetic acid was titrated with a methanolic solution of KOH under nonaqueous conditions.…”

Section: Hydroxyl Number Determinationmentioning

confidence: 99%

Catalyst‐Free Ring Opening Synthesis of Biodegradable Poly(ester‐urethane)s Using Isosorbide Bio‐Based Initiator

Mahdi

M'sahel

Medimagh³

2017

Macro Chemistry & Physics

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Polycaprolactones are obtained via ring opening polymerization of ε‐caprolactone in catalyst‐free condition. The polymerization is initiated in bulk, using isosorbide‐based amino‐alcohol as a biosourced initiator. The ratio of initiator to ε‐caprolactone, as well as to temperature, is optimized in order to tune the hydroxyl number (Nr. OH) and the average molecular weight of the polymers. In addition, these biocompatible polyesters are used as soft‐block to prepare thermoplastic poly(esterurethane)s elastomers via a simple one‐pot catalyst‐free polymerization. The successful synthesis of poly(esterurethane)s is confirmed by Fourier transform‐infrared spectroscopy, and the thermal properties are studied by differential scanning calorimetry. These novel materials exhibit glass transition temperatures ranging from 7 to 38 °C. The biodegradability of these elastomers is evaluated by enzymatic degradation tests performed at rt in phosphate buffer solution (pH ≈ 7.4). The mass loss of polymer films is around 3% after 4 weeks. Scan electron as well as atomic force microscopies are used to show the degradation patterns.

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Determination of hydroxyl value of vegetable oils‐based polyols through ring‐preopening, solvent‐extraction, and acetylation method

Li,

et al. 2024

J Americ Oil Chem Soc

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Vegetable oils‐based polyols prepared by epoxidation‐hydroxylation often have the phenomenon of the coexistence of epoxy and hydroxyl groups due to different ring‐opening degrees. The acylation method recommended by the American Society of Testing Materials (ASTM) standard (D1957‐86) and the Association of Official Analytical Chemists (AOAC) standard (965.32) is applicable only to fatty alcohols in oils and fats and their derivatives but not to vegetable oils‐based polyols since the residual epoxy groups in vegetable oils‐based polyols lead the tested hydroxyl value (OHV) to be higher than the actual OHV. A method combining ring‐preopening of residual epoxy groups, ether extraction of ring‐preopened vegetable oils‐based polyols, and subsequent acetylation by acetic anhydride‐acetic acid was established for OHV determination of vegetable oils‐based polyols. The accuracy of the method was verified by the known theoretical OHVs of short‐chain alcohols and simulated vegetable oils‐based polyols. The absolute values of relative deviations for OHVs of short‐chain alcohols and simulated vegetable oils‐based polyols were within 1.0% and 3.1%, respectively, which indicates the feasibility of the established method in eliminating the negative effects of residual epoxy groups in vegetable oils‐based polyols on OHV determination as well as accurately determining and evaluating the OHV of vegetable oils‐based polyols. The method can broaden the range of OHV determination up to 1800 mg KOH/g. The ratio of acetic anhydride and acetic acid and reaction time are key factors affecting the complete degree of acetylation, which can be regulated mutually in accurately determining the OHV of vegetable oils‐based polyols according to the practice. It is the first time, to our best knowledge, to establish a method to eliminate the negative effects of residual epoxy groups in vegetable oils‐based polyols on OHV determination. The established method provides a feasible method for polyol industry to accurately evaluate the product quality of vegetable oils‐based polyols.

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

Cited by 15 publications

References 13 publications

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

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

Catalyst‐Free Ring Opening Synthesis of Biodegradable Poly(ester‐urethane)s Using Isosorbide Bio‐Based Initiator

Determination of hydroxyl value of vegetable oils‐based polyols through ring‐preopening, solvent‐extraction, and acetylation method

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