propanal brief introduction

Propionaldehyde is a three carbon aldehyde with the molecular formula CH3CH2CHO. It is an isomer of acetone, a colorless liquid at room temperature, with a slightly irritating fruity odor. Propionaldehyde is mainly synthesized by hydrogenation and formylation of synthesis gas and ethylene in the presence of metal catalysts

propanal Basic information

propanal Numbering system

propanal Physical and Chemical Properties

• Appearance and characteristics:

• colorless liquid 

• Density:

• 0.805 g/mL at 25 °C(lit.)

• Boiling point:

• 48 °C

• Melting point:

• -81 °C

• Flash point:

• −16 °F

• Refractive index:

• n20/D 1.362(lit.)

• Water solubility:

• 540 g/L (20 ºC)

• Stability:

• Stable. Highly flammable. Incompatible with oxidizing agents, strong acids, strong bases.

• Storage conditions:

• The warehouse is ventilated, low-temperature and dry, and stored separately from oxidants

• Steam density:

• 2 (vs air)

• Steam pressure:

• 299mmHg at 25°C

security information

• RTECS号：

• UE0350000

• Safety instructions:

• S9-S16-S29

• Hazard category code:

• R11; R36/37/38

• WGK Germany：

• 1

• UN 1275 3/PG 2

• Dangerous goods transportation code:

• Customs code:

• 2912190090

• Hazard category:

• 3

• Packaging grade:

• II

• Dangerous goods signs:

• F

• Danger signs:

• GHS02, GHS05, GHS07

• Hazard description:

• H225; H302 + H332; H315; H318; H335

• Signal words:

• Danger

• Hazard prevention instructions:

• P210; P261; P280; P305 + P351 + P338

Production method and purpose

Production method

Although there are various methods for preparing acetaldehyde, industrial production did not begin until the early 1950s. In 1975, Union Carbide Corporation in the United States established a rhodium phosphine catalyst; After the first large-scale facility with an annual output of 45000 tons for the production of acetaldehyde through low-pressure carbonylation of ethylene, low-pressure carbonylation has gradually become the main method and development direction for acetaldehyde production. In 1981, the United States; More than 95% of the total production capacity of 230000 tons of acetaldehyde in Japan and Western Europe is produced through low-pressure carbonylation synthesis.

1. The carbonyl synthesis method consists of ethylene and carbon monoxide; Hydrogen is formed through a one-step reaction. Initially, cobalt carbonyl was used as a catalyst and carried out under high pressure (14.7-19.6 MPa). In recent years, a synthesis method using rhodium phosphine complexes as catalysts has been developed, with a reaction temperature of 100 ℃ and a pressure of 1.27-1.47MPa. This method produces no isomers and is easy to separate.

2. Epoxypropane isomerization method 1,2-epoxypropane is obtained by gas-phase isomerization in the presence of chromium vanadium catalyst. In addition, there are methods such as propanol oxidation and acrolein hydrogenation. When propylene is directly oxidized to produce acetone using palladium chloride as a catalyst, the by-product acetaldehyde is 0.5-1.5%. When the reaction temperature of palladium chloride content in the catalyst is increased, the proportion of acetaldehyde by-product can be increased to 50%.

3. Method: Add propanol to a reaction bottle equipped with a fractionation device (cooled in an ice water bath for the receiving bottle) and a dropping funnel (with the bottom extending into the bottom of the bottle)

(2) Heat 34g (0.567mol) and several zeolite particles until boiling. Add a solution of 56g (0.188mol) potassium dichromate, 300mL of water, and 40mL of concentrated sulfuric acid dropwise, and complete the addition in about 20 minutes. Keep the reaction system boiling and the top temperature of the distillation column not exceeding 75 ℃. After all the oxidants are added, continue the reaction for 15 minutes and collect fractions below 80 ℃. Separate water from the distillate, dry with anhydrous sodium sulfate, fractionate, and collect the fraction at 47-50 ℃ to obtain acetaldehyde

(1) 12g with a yield of 36%.

use to

Mainly used for the production of n-propanol, preservative raw material propionic acid, water-based polyethylene ester raw material dihydroxymethyl propionic acid, resin raw material trihydroxymethyl ethane, and water treatment acetone oxime. Propionaldehyde is also a polymerization inhibitor in the production of polyethylene, a promoter and anti-aging agent for synthetic resins and rubber, and can be used as an antifreeze agent, lubricant, dehydrator, etc. Propionaldehyde is widely used in industries such as pharmaceuticals, paints, plastics, fragrances, rubber, food and feed.