Acid-adjusting hydrolysis process for preparing levulinic acid

A technology for adjusting levulinic acid and acid, which is applied in the preparation of carboxylate salts, chemical instruments and methods, and the preparation of organic compounds. Effects of increasing production cost and technical difficulty, shortening hydrolysis time, and increasing cellulose content

Inactive Publication Date: 2010-04-07
HEILONGJIANG ACAD OF SCI INST OF NATURAL RESOURCES
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this reaction process is often unable to carry out the reaction completely due to the insufficient concentration of the dilute acid solution to the late stage of the reaction, thereby greatly reducing the yield of levulinic acid. Percentage; if the acid concentration is too high in the initial reaction, it is easy to carbonize the raw materials and damage the equipment

Method used

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  • Acid-adjusting hydrolysis process for preparing levulinic acid
  • Acid-adjusting hydrolysis process for preparing levulinic acid
  • Acid-adjusting hydrolysis process for preparing levulinic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 1. Raw materials: cellulose 40.13% corn stalks; sulfuric acid 98%, analytically pure.

[0021] 2. Preparation:

[0022] (1) Raw material pretreatment: Air-dry the corn stalks, pulverize them, and pass through a 30-mesh sieve. (3) Hydrolysis: use dilute sulfuric acid as a catalyst, add 2000ml of dilute sulfuric acid solution with a mass concentration of 3.8%, add corn stalks at a solid-to-liquid ratio of 1:19.5, stir evenly, and let stand at room temperature for 30 minutes to fully mix the feed liquid. Heating to 239.5°C within 3.2 minutes, reacting at 239.5°C and 2.4mPa pressure for 34.3 minutes, with a rotation speed of 100r / min. (4) Acid adjustment: quickly cool down to 50°C, reduce to normal pressure, reduce the rotating speed to 70r / min, inject 20ml of 20% sulfuric acid solution, then rapidly raise the temperature to 205°C, rotate at 160r / min, reaction pressure 2.2mPa, reaction time 20 minutes. (5) Detection of the target product: after the reaction is completed,...

Embodiment 2

[0024] 1. Raw materials: rice straw with 36.2% cellulose; 98% sulfuric acid, analytically pure.

[0025] 2. Preparation:

[0026] (1) raw material pretreatment: air-dry rice straw, pulverize, pass 30 mesh sieves; (3) hydrolysis: take dilute sulfuric acid as catalyst, add the dilute sulfuric acid solution 2000ml of mass concentration 3.9%, add rice straw according to solid-liquid ratio 1: 17.4 Straw, stir evenly, stand at room temperature for 30 minutes so that the feed liquid is fully mixed. Heating to 241.2°C within 3.5 minutes, reacting at 241.2°C and 2.4mPa pressure for 34.5 minutes, with a rotation speed of 120r / min. (4) Acid adjustment: quickly cool down to 50°C, reduce to normal pressure, reduce the rotating speed to 70r / min, inject 20ml of 20% sulfuric acid solution, then rapidly raise the temperature to 205°C, rotate at 160r / min, reaction pressure 2.2mPa, reaction time 20 minutes. (5) Detection of the target product: the reaction is completed, the solid-liquid is fi...

Embodiment 3

[0028] 1. Raw materials: Combined raw materials: corn stalks account for 40% of raw materials, rice stalks account for 40% of raw materials, and rice husks account for 20% of raw materials. The average cellulose content after mixing is 35.15%; sulfuric acid is 98%, analytically pure.

[0029] 2. Preparation:

[0030] (1) Raw material pretreatment: air-dry and pulverize corn stalks, rice stalks and rice husks, pass through a 30-mesh sieve, and combine the three raw materials in a ratio of 2:2:1. (3) Hydrolysis: take dilute sulfuric acid as a catalyst, add 2000ml of dilute sulfuric acid solution with a mass concentration of 3.7%, add combined raw materials by solid-liquid ratio 1: 17.9, stir evenly, and leave standstill at room temperature for 30 minutes to fully mix the feed liquid. Heating to 233.1°C within 3.8 minutes, reacting for 32.1 minutes under the conditions of 233.1°C and 2.3mPa pressure, with a rotation speed of 110r / min. (4) Acid adjustment: quickly cool down to 50...

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Abstract

The invention relates to an acid-adjusting hydrolysis process for preparing levulinic acid. The raw materials are ground, sieved and combined, and the concentration of the catalyst of sulfuric acid is adjusted to reduce the initial concentration of the reacted acid, thus the reaction can be carried out more moderate and environmental-friendly, and more importantly, the yield of the levulinic acid prepared with the acid-adjusting hydrolysis process can be greatly improved by 57.95 percent on average. In the invention, the waste agricultural crops such as the core straw, the rice straw and the rice husk which has the lowest utilization ratio are combined, thus the content of the cellulose in the raw materials are improved, and the carbonization to the rice husk from the acid is reduced. The cellulose can be thoroughly hydrolyzed in the reaction process through adjusting the concentration of the sulfuric acid in the reaction process, while the slag from other similar hydrolysis reaction contains part of the cellulose which is not hydrolyzed in the current time. The invention can avoid the raw material carbonization and the equipment damage which are resulted from the over high concentration of the acid.

Description

technical field [0001] The invention relates to an acid-adjusting hydrolysis method for preparing levulinic acid. Background technique [0002] Judging from the domestic and foreign situation of using biomass resources to prepare levulinic acid, there are two main technologies: furfuryl alcohol hydrolysis method and biomass direct hydrolysis method, and hydrolysis method is currently the mainstream. At present, the steps of using biomass resources to prepare levulinic acid by direct hydrolysis technology in China are as follows: put biomass raw materials and dilute acid solution into the reactor, and increase the yield of the target product by controlling different thermodynamic reaction conditions. But this reaction process is often because the concentration of dilute acid solution to the late stage of the reaction is insufficient, so that the reaction cannot be carried out completely, thereby greatly reducing the yield of levulinic acid. Percentage; if the concentration o...

Claims

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Application Information

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IPC IPC(8): C07C59/185C07C51/00
Inventor 于志民吕品郭文栋沈光周琳马献发王立民魏殿文张继舟曹宏杰师军
Owner HEILONGJIANG ACAD OF SCI INST OF NATURAL RESOURCES
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