Butadiene anti-polymerization agent TBC properties

p-tert-Butylhydroquinone: Chemical formula C10H14O2, molecular weight 166.22. Physical properties: Appearance and characteristics: colorless crystals. Melting point (°C): 52–57 Boiling point (°C): 285 Relative density (water = 1): 1.05 Relative vapor density (air = 1): No data Saturation vapor pressure (kPa): No data Heat of combustion (kJ/mol): No data Critical temperature (°C): No data Critical pressure (MPa): No data Logarithm of octanol/water partition coefficient: No data Flash point (°C): 151 Ignition temperature (°C): No data Upper explosive limit (% V/V): No data Lower explosive limit (% V/V): No data Solubility: Slightly soluble in hot water; soluble in ethanol, ether, propane, etc. Primary uses: Used as a polymerization inhibitor and antioxidant. Operating temperature: around 43 degrees. Operating pressure: around 380 KPa

Reply 1# comeonares: Where does the original poster work? Do you also use DMF in the production of butadiene? We need to regularly add TBC

Reply to 4# Kobayashi-ji: Introduction to polymerization inhibitors: Polymerization inhibitors react with chain radicals to form non-radical substances or low-reactivity radicals that cannot initiate further reactions, thereby terminating polymerization. 　　To prevent the polymerization of olefin monomers during storage, transportation, and other processes, a small amount of inhibitor is often added to the monomers, which is then removed before use. Generally, polymerization inhibitors are solid substances with low volatility, and can be removed during the distillation of monomers. The commonly used polymerization inhibitor hydroquinone can react with sodium hydroxide to form water-soluble sodium salts, so it can be removed by washing with a 5%–10% sodium hydroxide solution. Inorganic polymerization inhibitors such as cuprous chloride and ferric trichloride can also be removed by acid washing. Function: Inhibitors can prevent the progression of polymerization, resulting in an induction period during the polymerization process (a time interval during which the polymerization rate is zero). The length of this induction period is proportional to the amount of inhibitor present. Once the inhibitor is depleted, the induction period ends, and polymerization proceeds at the normal rate as if no inhibitor were present. Category: (1) Classified by their activity under different temperature conditions: ① Polymerization inhibitors with fixed activity that always react rapidly with free radicals within the normal storage and curing temperature ranges; they are consumed in these reactions, thereby creating an induction period. The polymerization inhibitors formed as a result of this consumption no longer possess activity, examples include hydroquinone. ②Thermosensitive polymerization inhibitors are inhibitors at normal storage temperatures; they decompose when heated and become ineffective, such as tert-butylhydroquinone. ③Dual-action inhibitors exert an inhibitory effect at lower temperatures and a catalytic effect at higher temperatures; examples include oxygen, organic copper salts, quaternary ammonium salts, sulfur, etc. (2) Classification according to their polymerization inhibition mechanism: ① In the absence of oxygen, in the presence of benzoin without oxygen, it reacts directly with free radicals to form a semiquinone intermediate, which then reacts with another free radical to form a stable compound. ②In the presence of oxygen, hydroquinone and its derivatives react with oxygen to form peroxyl radicals; these peroxyl radicals then react with hydroquinone to create radical complexes, which in turn react with another peroxyl radical to form stable compounds. (3) According to the composition of the inhibitor: ① Single-type: Only one type of inhibitor is required to achieve an inhibitory effect. Such as hydroquinone, paraquinone, etc. ②Composite type refers to the combined use of two or more polymerization inhibitors. To ensure the storage stability of the resin and prepregs at room temperature, and to enable adjustment of their shelf life without affecting the final curing rate of the finished products, a composite inhibitor is used in the manufacturing process. The above effect can be achieved by using hydroquinone and tert-butylhydroquinone along with trace amounts of copper salts. . w$ d# i! E/ j; W1 r Comparison of several inhibitors Hydroquinone HQ, also known as hydrogen quinone: the most commonly used one, with a low price. It performs well at room temperature, but its curing effect is poor when heated. 5 t! i3 q; Para-quinone PBQ: It can still function under anaerobic conditions and is suitable for etherification processes carried out under the protection of nitrogen or other inert gases. It has a yellow color, which affects the color of the resin. Methylhydroquinone THQ: It offers good performance and is used in the production of highly reactive unsaturated polyester resins; it is commonly used in topcoat resins and SMC resins. This product has good solubility and effective heat-resistant polymerization inhibition. p-Hydroxybenzyl ether HQMME: it confers good storage stability to the resin, without delaying or affecting its gelation time during use. This product has the best solubility in organic solvents and the lightest color. 　　2-tert-Butylhydroquinone MTBHQ: It is an effective storage stabilizer for unsaturated polyester resins, as well as a stabilizer for highly reactive resins. It has the most comprehensive functions and can perform well over a wide temperature range. Moreover, upon heating, it only causes a slight delay in the curing of the resin. This product is often used in combination with other polymerization inhibitors. 6 H4 z: `' ~6 k/ `7 y2 B9 _ 　　2,5-Di-tert-butylhydroquinone, or 2,5-DTBHQ: It can react slowly with free radicals over an extended period of time, thereby eliminating the free radicals that form during resin storage. It improves the storage stability of the resin while having the least impact on the gelation time.

Reply to 5# The Cultivator: Very comprehensive, I’ve learned something!