相关实验视频
Updated: Jun 27, 2025

08:43
Transformation of Organic Household Leftovers into a Peat Substitute
Published on: July 9, 2019
8.3K
BHT及其过氧化物 (BHTOOH) 的热分解特性
Suyi Dai1, Min Liang1, Haijun Cheng1
1School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, Guangxi, China.
BMC chemistry
|April 29, 2024
概括
2,6-Di-tert-butyl-4-methylphenol (BHT) 是稳定的,但其氧化产物BHTOOH迅速分解,造成热危害. 避免BHT氧化对于化学工业的安全至关重要.
科学领域:
- 化学工程是化学工程的重要组成部分.
- 材料科学 材料科学 材料科学
- 工业安全 工业安全 工业安全
背景情况:
- 2,6-Di-tert-butyl-4-methylphenol (BHT) 是一种广泛使用的抗氧化剂.
- BHT可以氧化为2,6-di-tert-butyl-4-hydroperoxyl-4-methyl-2,5-cyclohexadienone (BHTOOH) 的.
- 了解BHT和BHTOOH的热稳定性对于安全的生产和应用至关重要.
研究的目的:
- 为了比较BHT和BHTOOH的热稳定性和分解特性.
- 为了研究两种化合物的动力学和热分解产物.
- 评估与BHT及其氧化产品相关的潜在热危害.
主要方法:
- 对于热稳定性的迷你封闭式压力容器试验 (MCPVT).
- 差异扫描热量计 (DSC) 对于外热行为.
- 热重力测量分析 (TGA) 用于分解动力学.
- 气色谱-质谱 (GC-MS) 用于产品识别.
主要成果:
- 在气下,BHT表现出高达400K的稳定性.
- BHTOOH 显示了从 375.2 K 开始的快速热分解,初始外热温度为 384.9 K 和显著的热释放 (865.0 J/g).
- 表面激活能量为BHT的151.8kJ/mol和BHTOOH的66.07kJ/mol,每种类型的分解产品都有不同的分解产品形状.
结论:
- 由于其快速分解,BHTOOH具有显著的热危害.
- 该研究阐明了BHT和BHTOOH的分解途径和产物.
- 防止BHT的氧化对于减轻工业环境中的潜在热风险至关重要.
相关概念视频
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
1.8K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
1.8K
Hydroboration-Oxidation of Alkenes
8.1K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
8.1K
Regioselectivity and Stereochemistry of Hydroboration
8.1K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
8.1K
Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
2.6K
The addition of a hydrogen halide to 1,3-butadiene gives a mixture of 1,2- and 1,4-adducts. Since more substituted alkenes are more stable, the 1,4-adduct is expected to be the major product. However, the product distribution is strongly influenced by temperature; low temperature favors the 1,2-adduct, whereas the 1,4-adduct is predominant at high temperature.
2.6K
Radical Autoxidation
2.1K
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
2.1K
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.0K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
18.0K

