Pentaerythritol: molecular formula: C (CH2OH) 4, molecular weight: 136.15; properties: white crystal or powder, melting point: 261～262℃, boiling point: 380℃, density: 1.395 g/cm3, refractive index: 1.548, solubility: 1g is soluble in 18 mL water at 15℃. It is soluble in ethanol, glycerin, ethylene glycol, formamide, insoluble in acetone, benzene, carbon tetrachloride, ether and petroleum ether. Very stable in the air, not easy to absorb water, slightly sweet, basically non-toxic. Pentaerythritol reacts with aldehydes and ketones to produce acetals and ketones, reacts with nitric acid to produce pentaerythritol, reacts with organic acids and anhydrides to produce organic esters, reacts with hydrogen halide to produce pentaerythritol halides, and does not react with dilute caustic soda solution.

Pentaerythritol products generally include pentaerythritol (PE), dipentaerythritol (DPE) and tripentaerythritol (TPE). Different grades of products have different uses. It is generally considered that dipentaerythritol and tripentaerythritol are high-grade series products, mainly used to synthesize high-grade coating and lubricating oil.

Pentaerythritol is mainly used in coating industry in China. It can be used to produce alkyd resin coating, which improves the hardness, luster and durability of coating film. It is also used for color paint, varnish and printing ink required by the raw materials of rosin, and can be made of dry oil, smouldering paint and fang air lubricants. The fatty acid ester of pentaerythritol is a highly effective lubricant and PVC plasticizer, and its epoxy derivative is the raw material for the production of non-ionic surfactants. Pentaerythritol is easy to form complex with metals and is also used as a hard water softener in detergent formulations. In addition, it is also used in medicine, pesticides and other production.

Tetra-alcohol molecules contain four equivalent hydroxymethyl groups and have a high symmetry, so they are often used as raw materials for the production of multi-functional compounds, for example, the production of pentaerythritol triacrylate (PETA), etc.

technical principle

Pentaerythritol is synthesized from formaldehyde and acetaldehyde catalyzed by sodium hydroxide.
CH3CHO+4HCHO+NaOH→C(CH2OH)4+HCOONa

The reaction is carried out in two steps. In the first step, three molecules of formaldehyde and one molecule of acetaldehyde are reacted by alder to produce trimethylated acetaldehyde:

CH3CHO+3HCHO→C(CH2OH)3CHO

Then trimethylol acetaldehyde reacts with formaldehyde in Conicharo to be reduced to pentaerythritol, formaldehyde is oxidized to formic acid, and formic acid forms sodium formate in sodium hydroxide medium.

C(CH2OH)3CHO+HCHO+NaOH→C(CH2OH)4+HCOONa

The reaction mechanism can be expressed as follows.
CH3CHO+HCHO→HOCH2CH2CHO→HC(CH2OH)2CHO→C(CH2OH)3CHO→C(CH2OH)4+HCOONa

Formaldehyde reacts with acetaldehyde under alkaline conditions to produce pentaerythritol and formate. Excess alkali is neutralized with formic acid. The reaction liquid enters the dealdehyde column to remove excess formaldehyde, and then enters the evaporator for concentration. The concentrated liquid is cooled, crystallized, centrifuged and washed, and then dried to obtain pentaerythritol. High purity pentaerythritol can be obtained by recrystallization of crude pentaerythritol after dissolution and decolorization. Mother liquor goes to recovery section to recover sodium formate and pentaerythritol.

Pentaerythritol process flow chart

1,  Continuous crystallization, continuous production, product quality stability, large crystallization particles.
2,  Mother liquid and material were separated by continuous belt vacuum centrifuge.
3,  Plenty of product varieties, low consumption, by-product recovery completely, small pollution, high degree of automation and mechanization.

Main raw material consumption

Specifications of Pentaerythritol products（95%）

Pentaerythritol product specifications (98%)

Dipentaerythritol product specifications

 Sodium formate product specifications