阅读说明：本技术 一种3-甲基-2-硝基苯甲酸废水的资源化利用方法 (Resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater ) 是由 董翠平 马丽涛 乔琼琼 尤健健 徐培洋 杨道顺 朱海涛 于 2020-06-11 设计创作，主要内容包括：本发明提供了一种3-甲基-2-硝基苯甲酸废水的资源化利用方法,包括以下步骤：向反应釜中加入废水,加入清水或不加清水,搅拌混合均匀后,加入一定量的磺化剂,搅拌混合均匀,加入碱调节pH值,磺化保温,滴加丙酮,丙酮滴加完毕,继续缓慢滴加甲醛,滴加完毕,缩合保温,保温结束降温即可。通过本发明的资源化利用方法,无需对废水进行其他处理即可直接作为磺化丙酮甲醛缩合物类分散剂的合成原料,得到的分散剂可提高混凝土的强度,提高建筑物的安全性能。(The invention provides a resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater, which comprises the following steps: adding wastewater into a reaction kettle, adding clear water or not, stirring and mixing uniformly, adding a certain amount of sulfonating agent, stirring and mixing uniformly, adding alkali to adjust the pH value, sulfonating and preserving heat, dropwise adding acetone, continuously and slowly dropwise adding formaldehyde after the dropwise adding of the acetone is finished, condensing and preserving heat after the dropwise adding is finished, and cooling after the heat preservation is finished. By the resource utilization method, the waste water can be directly used as a synthetic raw material of the sulfonated acetone-formaldehyde condensate dispersant without other treatment, and the obtained dispersant can improve the strength of concrete and the safety performance of buildings.)

1. A resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater is characterized by comprising the following steps: adding wastewater into a reaction kettle, adding clear water or not, stirring and mixing uniformly, adding a sulfonating agent, stirring and mixing uniformly, adding alkali to adjust the pH value, sulfonating and preserving heat, dropwise adding acetone, continuously and slowly dropwise adding formaldehyde after the dropwise adding of the acetone is finished, condensing and preserving heat after the dropwise adding is finished, and cooling after the heat preservation is finished.

2. The method for recycling 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, wherein the sulfonating agent is one or more of sodium sulfite, sodium bisulfite and sodium metabisulfite.

3. The resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, characterized in that the sulfonating agent is obtained by compounding one or more of sodium sulfite, sodium bisulfite and sodium pyrosulfite with one or two of sodium styrene sulfonate and sodium sulfanilate.

4. The resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, characterized in that the alkali is solid sodium hydroxide or sodium hydroxide aqueous solution, and the pH value is adjusted to 7-10 by adding alkali.

5. The resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, characterized in that the mass ratio of the sulfonating agent to acetone is 0.9:1-1.6: 1.

6. The resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, characterized in that the mass ratio of the formaldehyde solution to acetone is 2.5:1-2.9:1, and the mass percentage concentration of the formaldehyde solution is 35% -37%.

7. The resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, characterized in that the sulfonation heat preservation temperature is not more than 50 ℃ and the heat preservation time is 0-1 h.

8. The resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, which is characterized in that the temperature is not more than 55 ℃ in the process of dripping acetone, and the dripping time is 20-40 min; the dripping time of the formaldehyde is 1-5h, and the temperature is not more than 95 ℃ in the dripping process.

9. The resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater as claimed in claim 1, characterized in that the condensation heat preservation temperature is 90-96 ℃, and the heat preservation time is 1.5-3 h.

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater.

Background

Energy has been a cornerstone of world progress and development, with coal, oil and gas being several conventional forms of energy. In the total energy consumption of China, 22.5 percent of petroleum, 72.9 percent of coal and 4.6 percent of other energy. China is a country with more coal and less oil, oil resources are relatively poor, coal resources are abundant, and in decades in the future, coal can continuously play a role of main energy in China, but the direct combustion utilization of coal causes lower utilization efficiency and serious climate deterioration and environmental pollution.

The comprehensive consideration of energy safety and environmental problems, and the clean utilization of coal resources are increasingly paid attention. Clean coal technology has been proposed for 30-40 years, and for further improving the utilization rate of coal, meeting the environmental protection standard and improving the economic utilization value of coal, the following three improvements are mainly provided: the discharge amount of greenhouse gas carbon dioxide is reduced by improving the recycling of carbon; combustion technology is improved so as to improve the effective utilization rate of coal; and the emission of environmental pollutants such as sulfur dioxide, nitrogen oxides, solid particles and the like is controlled. In the current world facing the oil crisis, new energy substitutes are researched, and coal water slurry is one of the substitutes.

The coal water slurry is used for replacing coal for combustion, and has the advantages of high combustion benefit, environmental pollution reduction, convenience in load adjustment, coal saving, labor condition improvement and the like. The coal water slurry technology is a clean coal technology which is efficient, safe, economical, clean and simple to operate. Coal water slurry is beginning to be highly valued as a new oil-substituting fuel in many countries. The coal water slurry is a solid-liquid two-phase coarse dispersion system, has lower viscosity and better fluidity in normal use, has higher viscosity when in rest, is not easy to form precipitates, and is necessary to add a small amount of chemical additives in the process of preparing the coal water slurry. The influence factors influencing the high-efficiency utilization of the coal water slurry are quite many, and the development of the dispersing agent has a key effect on the coal water slurry technology.

In recent years, many researches are made on coal water slurry additives at home and abroad, and a series of competitive products are produced. The research and application of the coal water slurry dispersing agent are prominent in foreign Nippon oil ester company, Kao corporation, and the Across corporation. A series of good dispersants such as sodium polystyrene sulfonate (PSS), naphthalene sulfonate polymer (NSF), etc. have been developed by japanese researchers and have been used in industrial production. The national brewing company of America synthesizes a nonionic dispersant as the water-coal-slurry dispersant, which can lead the concentration of the prepared water-coal-slurry to reach 70 percent and has ideal stability and fluidity. The coal water slurry NDF dispersant developed by Nanjing university at home is suitable for wide coal types and has good performance. The water coal slurry additive synthesized by Kunzhan fine chemical company of Kunzhan city, Jiangsu province has certain performance even exceeding that of similar Japanese products. HNF developed by Huainan mining group synthetic material Limited liability company can simultaneously give consideration to the dispersibility and stability of the coal water slurry.

The total amount of coal resources in China is rich, the resource reserves of coal in China are 15663.1 hundred million tons, and the low-rank coal accounts for more than 50 percent. In the existing pulping technology, low-rank coal is difficult to prepare high-concentration coal water slurry. And the dispersant used for the coal water slurry mainly comprises naphthalene series, lignin series, humic acid series, sulfonated acetone-formaldehyde condensate, nonionic dispersant and the like. However, most of these dispersants are produced from petroleum products, which are expensive and easily cause environmental pollution. And the pulp concentration of the coal is not high, and the pulp concentration of the coal is between 59 and 61 by using low-rank coal and immature coal generally.

The water reducing agent is used as the most additive for concrete, can reduce the water consumption in concrete mixtures, and has a good effect on improving the concrete performance of concrete. At present, the three-generation water reducing agent is researched and produced at home and abroad, the first generation is a common water reducing agent, the aliphatic water reducing agent (sulfonated acetone-formaldehyde condensate), the sulfamic acid high-efficiency water reducing agent (sulfamic acid-formaldehyde condensate) and the naphthalene water reducing agent (naphthalene sulfonate-formaldehyde condensate) are used as the second generation high-efficiency water reducing agent, and compared with the third generation which is a polycarboxylic acid high-performance water reducing agent, the water reducing and collapse keeping performances of the second generation high-efficiency water reducing agent are much poorer due to the defects of the structure of the second generation high-efficiency water reducing agent, but the naphthalene water reducing agent, the aliphatic water reducing agent and the sulfamic acid high-efficiency water reducing agent have wide raw material sources.

The by-products (hereinafter referred to as 3-methyl-2-nitrobenzoic acid wastewater) generated in the production process of 3-methyl-6-nitrobenzoic acid or 3-methyl-2-nitrobenzoic acid, which is an intermediate of medicines and pesticides, mainly comprise water, 3-methyl-2-nitrobenzoic acid, a small amount of 3-methyl-6-nitrobenzoic acid and a small amount of 3-methyl-4-nitrobenzoic acid, and the continuous separation and purification treatment has large energy consumption, so that the waste of resources and energy sources is caused, or secondary environmental pollution is possibly caused.

The conventional sulfonated acetone-formaldehyde condensate dispersant is prepared by using acetone, sodium metabisulfite/sodium sulfite/sodium bisulfite, formaldehyde and the like as raw materials and performing a step-by-step aldol condensation reaction under certain reaction conditions through a carbanion reaction process under the condition of dilute alkali to form aldehyde ketone with beta-OH. In the reaction, formaldehyde with high carbonyl activity is added to carry out complex copolycondensation reaction, and proper alkalinity and temperature are controlled in the presence of sulfonating agent to form aliphatic chain compound containing unsaturated bonds, wherein molecular chains of the aliphatic chain compound contain-SO₃H. -OH and conjugated double bonds, which are negative ionic surfactants.

Disclosure of Invention

The invention aims to provide a resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater, which can be directly used as a synthetic raw material of a sulfonated acetone-formaldehyde condensate dispersant without carrying out other treatment on the wastewater, and the obtained dispersant can improve the strength of concrete and the safety performance of buildings.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a resource utilization method of 3-methyl-2-nitrobenzoic acid wastewater comprises the following steps: adding wastewater into a reaction kettle, adding clear water or not, stirring and mixing uniformly, adding a sulfonating agent, stirring and mixing uniformly, adding alkali to adjust the pH value, sulfonating and preserving heat, dropwise adding acetone, continuously and slowly dropwise adding formaldehyde after the dropwise adding of the acetone is finished, condensing and preserving heat after the dropwise adding is finished, and cooling after the heat preservation is finished.

Preferably, the sulfonating agent is one or more of sodium sulfite, sodium bisulfite and sodium metabisulfite.

Preferably, the sulfonating agent is obtained by compounding one or more of sodium sulfite, sodium bisulfite and sodium pyrosulfite with one or two of sodium styrene sulfonate and sodium sulfanilate.

Preferably, the alkali is solid sodium hydroxide or sodium hydroxide aqueous solution, and the pH value is adjusted to 7-10 by adding the alkali.

Preferably, the mass ratio of the sulfonating agent to acetone is 0.9:1-1.6: 1.

Preferably, the mass ratio of the formaldehyde solution to the acetone is 2.5:1-2.9:1, and the mass percentage concentration of the formaldehyde solution is 35-37%.

Preferably, the sulfonation heat preservation temperature is not more than 50 ℃, and the heat preservation time is 0-1 h.

Preferably, the temperature is not more than 55 ℃ in the dropping process of the acetone, and the dropping time is 20-40 min; the dripping time of the formaldehyde is 1-5h, and the temperature is not more than 95 ℃ in the dripping process.

Preferably, the condensation heat preservation temperature is 90-96 ℃, and the heat preservation time is 1.5-3 h.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention utilizes 3-methyl-4-nitrobenzoic acid, 3-methyl-2-nitrobenzoic acid and 3-methyl-6-nitrobenzoic acid in 3-methyl-2-nitrobenzoic acid wastewater to provide a branched chain taking a benzene ring as a main body for sulfonated acetone formaldehyde condensate macromolecules in the synthesis process of sulfonated acetone formaldehyde condensate water reducing agents or water-coal-slurry dispersing agents, can change the molecular structure of the sulfonated acetone formaldehyde condensate water reducing agents or the water-coal-slurry dispersing agents, has better dispersion effect in cement or water-coal-slurry, and has more obvious slump retaining effect in concrete.

2. The invention utilizes the functional groups of 3-methyl-2-nitrobenzoic acid, 3-methyl-6-nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid introduced by 3-methyl-2-nitrobenzoic acid wastewater to improve the strength of concrete, and compared with a common aliphatic water reducing agent, the invention can increase the strength of concrete by more than 50 wt% and improve the safety performance of buildings.

3. The invention utilizes the waterproof and antiseptic properties of 3-methyl-2-nitrobenzoic acid, the obtained dispersant can prevent the corrosion of concrete reinforcing bars and the mildew of concrete, improve the durability of buildings, and prolong the effective period of the obtained dispersant due to the antiseptic effect. And the efflorescence phenomenon of the concrete can be eliminated, and the falling-off phenomenon of the building surface is prevented.

4. The method realizes the resource utilization of the 3-methyl-2-nitrobenzoic acid wastewater, does not need to carry out other treatment on the wastewater, directly uses the wastewater as a synthetic raw material of the sulfonated acetone-formaldehyde condensate dispersant, increases the calorific value when the organic components of the wastewater are used for the combustion or gasification of the coal water slurry, does not damage and pollute human bodies and the environment, and does not cause the waste of resources and energy.

Drawings

FIG. 1 is a liquid chromatogram of 3-methyl-2-nitrobenzoic acid wastewater containing 10 wt% of solids in the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.