Preparation method of mannitol

Abstract

The invention relates to a preparation method of mannitol. The technique comprises the following steps: extracting glossy privet leaf of triterpenic acid as a raw material, using 15-20 times (V / W) of deionized water to extract for 1.5-2 hours, carrying out ultrafiltration on extracting solution by an ultrafiltration membrane system with molecular weight cut off of 20000, heating and concentrating permeate till the relative density is 1.30-1.32, standing and crystallizing, using the deionized water to dissolve coarse crystal, boiling for 5 minutes, filtering with heat, recrystallizing for three times, using ether to clean, and drying at the temperature of 80-90 DEG C to obtain a product. The technique has simple operation, lower cost and higher purity and is beneficial to large-scale production operation.

Description

technical field The invention relates to a method for preparing mannitol, in particular to a method for extracting mannitol from privet leaf extraction residue. Background technique Mannitol, also known as D-mannitol and wood honey, is an isomer of sorbitol, both of which are hexavalent alcohols. English name: Mannitol Molecular formula: C 6 h 14 o 6 Molecular weight: 182.17 White needle crystal. The melting point is 166°C, the relative density is 1.52, 1.489 (20°C), and the boiling point is 290-295°C (467kPa). 1g of this product is soluble in about 5.5ml of water (about 18%, 25°C), 83ml of alcohol, more soluble in hot water, soluble in pyridine and aniline, and insoluble in ether. The aqueous solution is alkaline. With the chemical properties of polyols, it can be esterified, etherified, oxidized, and dehydrated. It is the only non-hygroscopic crystal among polyols. In the prior art, mannitol is usually chemically synthesized, but there are many problems: the...

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Problems solved by technology

In the prior art, mannitol is usually chemically synthesized, but there are many problems: the glucose electrolysis method has low efficiency, high energy consumption, and low purity; the products of the reduction method of polysaccharides have isomerization problems, and the cost is high and the purity is low; The source of raw materials for the sugar reduction method is problematic, etc.

The extraction method of mannitol mainly uses kelp as raw material, the quality of the obtained mannitol is poor, it is difficult to filter, and the production cost is high, so further purification is required

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