It is expressed as the amount of KOH in mg to neutralize the consumed equivalent amount of acetic acid used for the acetylation of 1 g of sample. Information and translations of hydroxyl value in the most comprehensive dictionary definitions resource on the web. FT-NIR Spectroscopy, Hydroxyl Value, Polyol, Polyurethane hydroxide (KOH). It is the number of Nitrogens x 56.1 (Mwt of KOH) x 1000 (convert to milligrams) divided by molecular mass of the amine functional compound. Login . The hydroxyl number, defined as mg KOH/g of a sample can calculated as follows: OH= (B-A)*M*56.1/w +acid number. 25.2 PRINCIPLE The process consists of The hydroxyl value detection method includes the steps of: weighing sample in a container, and taking another empty container; pipetting an acetic anhydride-imidazole-pyridine solution into The result is reported in milligram of potassium hydroxide titrated by a sample of 1 g Weigh accurately about 5 gm of the powdered drug in a tarred silica crucible. Hydroxyl value refers to the number of mg of KOH required to neutralize the acetic acid capable of combining by acetylation with 1 g of fat. Acetyl value refers to the number of mg of KOH required to neutralize the acetic acid liberated by the hydrolysis of 1 g of acetylated oil or fat. A method for the rapid determination of the hydroxyl value of oils, fats and related products is described. The method uses toluene-p-sulphonic acid as a catalyst and this allows the sample, dissolved in toluene, to be acetylated in 10 min at room temperature. ESTIMATION OF VOLATILE ACIDS PRINCIPLE: Steam distillation after acidifying the sample with 1+1 H 2 SO 4 results in the evaporation of volatile acids which on condensation yield liquefied volatile acids. This method is based on reacting the hydroxyl compound with hexamethyldisilazane (HMDS) and 05 v/w V = difference in ml during titration W = wt. The determination described in this report is based on the standards DIN EN ISO 46292:2016 (Hydroxyl - value) and DIN EN ISO 2114:200206 (acid value). 4 PRINCIPLE Acetylation of the hydroxyl groups by acetic anhydride is The blank value is stored as auxiliary value The acid value for castor oil is about 2.0 giving a hydroxyl value for the above sample of 156. The hydroxyl value is a reference number used to characterize polyoles. It is expressed as the amount of KOH in mg to neutralize the consumed equivalent amount of acetic acid used for the acetylation of 1 g of sample. Two titration methods are used in this analysis: a blank and a sample titration. What does hydroxyl value mean? Reaction with acetic anhydride is used in pharmacopoeial assays of: benzyl alcohol and dienestrol and determination of hydroxyl values of castor oil, cetosteryl alcohol and cetomacrogol. Additionally, sodium hydroxide may be The acid value is based on the quantity of potassium hydroxide required to neutralize one gram of free acid in one gram of fats, oils, or similar substances. Hydroxyl Group Definition. The method is a modification Incinerate the powdered drug by gradually The hydroxyl value can be calculated using the following equation. The number of reactive hydroxyl groups (OH) on the polyol directly impacts the quantity of urethane linkages, which greatly influences the physical properties of the final polyurethane product. CALCULATION: Hydroxyl value = acid value + 28. 5.1 Hydroxyl is an important functional group and knowledge of its content is required in many intermediate and end use applications. Continue reading here: Nonaqueous titration of weak bases A primary Fourier transform infrared (FTIR) method was developed to determine the hydroxyl value (OHV) of polyols produced from edible oils. A titrimetric method for determining the free hydroxyl groups in binders and binder solutions for paints and varnishes. The hydroxyl value is an indicator of the reactivity of the acrylic resins functionalized with hydroxyl functions (ie the number of OH group available). A primary Fourier transform infrared (FTIR) method was developed to determine the hydroxyl value (OHV) of polyols produced from edible oils. 2. hydroxyl value number of milligrams of potassium hydroxide (KOH) corresponding to hydroxyl groups that have been acetylated under specified test conditions in 1 g of the product tested in grams of substance. The hydroxyl value is a reference number used to characterize polyoles. Pyridine suitable for hydroxyl value determination, 99.5%; CAS Number: 110-86-1; EC Number: 203-809-9; find Sigma-Aldrich-246535 MSDS, related peer-reviewed papers, technical documents, similar products & more at Sigma-Aldrich The equivalent conductances of hydrogen and hydroxyl ions at the very small concentrations existing in pure water may be taken as equal to the accepted values at infinite dilution these In analytical chemistry, the hydroxyl value is defined as the number of milligrams of potassium hydroxide required to neutralize the acetic acid taken up on acetylation of one gram of a The hydroxyl value (or hydroxyl number) method measures the number of -OH groups on a molecule. Note that a chemical substance may also have a measurable acid value affecting the measured end point of the titration. 3) As a result, acetic acid is formed which is then back-titrated with methanolic KOH solution. The hydroxyl value is a reference number used to characterize polyoles. It is expressed as the amount of KOH in mg to neutralize the consumed equivalent amount of acetic acid used for the acetylation of 1 g of sample. 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 The milligrams of potassium hydroxide required to neutralize one gram of the solution is called the hydroxyl The indicator was a 1% phenolphthalein solution in pyridine. It is usually expressed as the KOH mass in mg equivalent to the amount of acetic acid reacting during the acetylation of 1g of resin. It is expressed as the amount of KOH in mg to neutralize the consumed equivalent amount of acetic acid used for The hydroxyl value is a reference number used to characterize polyoles. a). 1. Two titration methods are used in this analysis: a blank and a sample titration. A hydroxyl group is a functional group that attaches to some molecules containing an oxygen and hydrogen atom, bonded together. A relatively simple method is described for routine determination of hydroxyl values for a wide range of hydroxyl containing compounds including soybean oil polyols, polyols derived from soy meal, polyether polyols and ethylene glycol as well as their blends. The hydroxyl number (OH#) is a measure of the concentration of the hydroxyl groups on the polyol. Determination of total ash value. hydroxyl value The number of milligrams of potassium hydroxide necessary to neutralize the acetic acid which will combine, by acetylation, with 1 g of an unsaturated polyester resin. The presented titration system can be used for the fully automated determination of the hydroxyl number (HN) according to ASTM E1899 and EN ISO 4629-2. Hydroxyl value refers to the 2 KOH in ethanol, 0.5 mol/L (Titration reagent hydroxyl value) 3 Toluene 4 Ethanol 5 Deionized water 6 N-Methyl-2-Pyrrolidon 7 Acetic anhydride 8 4-N-Dimethylaminopyridine 9 N-Methyl-2 This part of ISO 4629 specifies a titrimetric method for determining the hydroxyl value of resins, binders for paints and varnishes, primary alcohols, glycols and fats. In analytical chemistry, the hydroxyl value is defined as the number of milligrams of potassium hydroxide required to neutralize the acetic acid taken up on acetylation of one gram of a chemical substance that contains free hydroxyl groups. So using Tetraethylenepentamine (TEPA) 3.2 Also spelled hydroxy, this functional group provides important functions to both alcohols and carboxylic acids. This test method is for the determination of primary and secondary hydroxyl groups and can be used for the assay of com The hydroxyl value of a fatty alcohol or ethoxylate is defined as the number of milligrams of potassium hydroxide required to neutralise the acid required to esterify the hydroxyl groups Determination of acid value. Acid number (2114)-Hydroxyl number(4629-2)_us.docx 1/8 SI Analytics-Application report Titration Determination of hydroxyl value (DIN EN ISO 4692-2) and acid value (DIN EN ISO 2114) Description . 3 DEFINITION hydroxyl value : The number of milligrams of potassium hydroxide necessary to neutralize the acetic acid which will combine by acetylation with 1 g of the unsaturated polyester resin. Iodine value and hydroxyl value of DCO, obtained at atmospheric and reduced pressure (500 mbar), were determined as 135.8 and 140, and 12.3 and 11.9, respectively, using