アプリケーション検索（技術資料）

Hydroxyl is an important functional group and knowledge of its content is required in many intermediate and end-use products such as polyols, resins, lacquer raw materials and fats (petroleum industry). The test method to be described determines primary and secondary hydroxyl groups. The hydroxyl number is defined as the mg of KOH equivalent to the hydroxyl content of 1 g of sample.The most frequently described method for determining the hydroxyl number is the conversion with acetic anhydride in pyridine with subsequent titration of the acetic acid released: H3C-CO-O-CO-CH3 + R-OH -> R-O-CO-CH3 + CH3COOH. However, this method suffers from the following drawbacks: - The sample must be boiled under reflux for 1 h (long reaction time and laborious, expensive sample handling) - The method cannot be automated - Small hydroxyl numbers cannot be determined exactly - Pyridine has to be used, which is both toxic and foul-smellingBoth standards, ASTM E1899-08 and DIN 53240-2, offer alternative methods that do not require manual sample preparation and therefore can be fully automated: The method suggested in ASTM E1899-08 is based on the reaction of the hydroxyl groups attached to primary and secondary carbon atoms with excess toluene-4-sulfonyl-isocyanate (TSI) to form an acidic carbamate. The latter can then be titrated in a non-aqueous medium with the strong base tetrabutyl- ammonium hydroxide (TBAOH). The method suggested in DIN 53240-2 is based on the catalyzed acetylation of the hydroxyl group. After hydrolysis of the intermediate, the remaining acetic acid is titrated in a non-aqueous medium with alcoholic KOH solution. The present work demonstrates and discusses an easy way to determine the hydroxyl number according to ASTM E1899-08 or DIN 53240-2 with a fully automated titrimetric system for a great variety of industrial oil samples.

This Application Bulletin describes a simple polarographic method to determine monomeric styrene in polymers. The limit of determination lies at 5 mg/L. Before the determination, styrene is converted to the electrochemically active pseudonitrosite using sodium nitrite.

The present Application Bulletin elucidates several applications for the polymer industry that can be carried out with the aid of NIR instruments. This Bulletin contains analyses of a wide range of parameters in a very large array of samples. The hydroxyl number is one of the best-known of the parameters that can be determined rapidly using near-infrared spectroscopy. The determination of the hydroxyl number in different areas and in different polyol types is also a part of this Bulletin. Each application describes the sample and the instrument that was originally used for the analysis, as well as the recommended instruments and the results.

This Application Note describes a fast, nondestructive, and reliable NIRS method for the determination of the hydroxyl number in polyols. Results are available in real-time for which reason NIRS is highly suited for in-process quality control. Second-derivative spectra and linear least-squares regression provide results that match very well with those obtained by titration.

During polymerization, real-time determination of hydroxyl and acid numbers of polyols provide important information about molecular weight and the reaction end point. This Application Note sheds light on the practical aspects of process monitoring in a polyol batch process using NIRS methodology. Real-time process monitoring with NIRS is the key to lower production costs and better product quality.

Determination of the vinyl content of silicone rubber is a lengthy and challenging process. First, the vinyl groups must be converted to ethylene by reacting with an acid, followed by the determination of the produced ethylene with gas chromatography (GC).This application note demonstrates that Vis-NIR (visible near-infrared) spectroscopy provides a cost-efficient and fast solution for the determination of vinyl content in silicone rubbers. With the DS2500 Solid Analyzer it is possible to obtain results in less than a minute without sample preparation or any chemical reagents.

テレフタル酸、イソフタル酸、5-スルホイソフタル酸などといった芳香族ジカルボン酸は、ポリエステルやアルキド樹脂の製造において重要なモノマーです。ジカルボン酸のモノマーの比率は、重合に多大な影響を及ぼします。Metrosep A Supp 15 - 50/4.0 の短いタイプのカラムを高い溶離剤濃度および高い流量で使用すれば、後から溶出される成分の分離は15分で完了します。

エポキシ樹脂のエポキシ含有量は、樹脂の反応性および樹脂硬化プロセスによって得られるコーティングの特性に強く影響を与えます。そのため、エポキシ含有量は、メーカーおよび消費者にとって重要な品質管理指標となります。 エポキシ含有量の分析は、サンプル中のエポキシ基と臭化水素の反応に基づいています。臭化水素は、臭化テトラエチルアンモニウム（TEABr）と過塩素酸滴定溶液との反応によって生成されます。 規格 EN ISO 3001 および ASTM D1652 では、エポキシ含有量をエポキシ当量（EEW）として滴定によって測定する方法が定められています。手動滴定の代わりに電位差自動滴定装置 タイトランドとSolvotrode easyClean電極を使用することで、測定の再現性および反復性が大幅に向上します。

Determination of styrene monomers in polystyrene. Free styrene is converted to a polarographically active pseudonitrosite.

This e-book explains how Raman and near-infrared (NIR) spectroscopy enable rapid, nondestructive polymer analysis, ensuring high quality while reducing costs and waste.

一般的にポリウレタンなどの化学品の製造は環境に悪影響を与える上に、非常にコストのかかる製造工程と言われています。これらは振動分光法のシステムを用いることによって著しい改善を見込むことができます。このホワイトペーパーでは、化学プラントで振動分光法の一種であるNIR分光法やラマン分光法を用いることでオペレーティングコストを削減し、環境への影響を最小限に抑える一例を紹介します。