CN104447353B

CN104447353B - A kind of benzene and hydroxylamine salt react the method directly preparing aniline

Info

Publication number: CN104447353B
Application number: CN201410751845.4A
Authority: CN
Inventors: 张艳华; 王延吉; 张东升
Original assignee: Hebei University of Technology
Current assignee: Hebei University of Technology
Priority date: 2014-12-10
Filing date: 2014-12-10
Publication date: 2016-06-22
Anticipated expiration: 2034-12-10
Also published as: CN104447353A

Abstract

The present invention is a kind of method that benzene reacts directly aniline processed with hydroxylamine salt, the method comprises the steps: to be separately added into acetic acid, water, hydroxylamine salt, benzene and catalyst in the normal pressure reactor with condensation reflux unit, being warming up to 70-80 DEG C, stirring the lower response time is 2-5h, obtains aniline；Wherein, volume ratio is acetic acid: water: benzene=5:5:1, and quality is than benzene: catalyst=5～20:1, mol ratio benzene: hydroxylamine salt=1:1, and described catalyst is that the vanadium dioxide catalyst that Carbon Materials supports (is called for short VO₂/ C), active component VO in this catalyst₂Account for the 3～25% of catalyst gross mass。The selectivity of aniline of the present invention is up to 99%, and yield is up to 41%, and the preparation process of catalyst is simple, with low cost, environmental friendliness, easily operate。

Description

A kind of benzene and hydroxylamine salt react the method directly preparing aniline

Technical field

The present invention relates to a kind of benzene and react, with hydroxylamine salt, the method directly preparing aniline, the vanadium dioxide catalyst that a kind of Carbon Materials supports the specifically method that directly catalysis benzene reacts one-step synthesis aniline with hydroxylamine salt under gentle reaction condition。

Background technology

Aniline is a kind of important Organic Chemicals and fine-chemical intermediate, it is widely used in the industries such as medicine, dyestuff, rubber, spice, also it is the primary raw material producing '-diphenylmethane diisocyanate (MDI), along with the increase of MDI demand, the demand of aniline also there is bigger growth。At present, the industrial process of aniline is mainly By Catalytic Hydrogenation of Nitrobenzene method and phenol vapor phase ammonia solution。The By Catalytic Hydrogenation of Nitrobenzene method first step first uses the mixed liquor of concentrated nitric acid and concentrated sulphuric acid by nitrated for benzene generation Nitrobenzol at 90-140 DEG C, generates aniline then through liquid phase or gas-phase catalytic hydrogenation after rectification is reclaimed。This synthetic method not only energy consumption is high, etching apparatus, and can produce a large amount of acid sludge, NO_xWaste gas and the waste water containing phenol, cause severe contamination to environment。Phenol vapor phase ammonia solution rule is that phenol and ammonia react generation aniline under the high temperature of about 400 DEG C。The synthesis of industrial raw material phenol mainly adopts cumene method, namely with benzene and propylene for raw material, through AlCl₃Catalyzing and synthesizing isopropylbenzene, isopropylbenzene generates peroxide through air oxidation, and peroxide decomposition under diluted acid exists finally gives phenol and acetone。Visible, the problem such as the industrial process of these aniline all exists severe reaction conditions, step is many, energy consumption is high, cost is high, atom utilization is low and environmental pollution is serious。Therefore, for adapting to the greenization trend of whole world Chemical Manufacture, it would be highly desirable to develop new aniline synthetic route simple, eco-friendly。In recent years, by the direct ammoxidation synthesis aniline of benzene, multistep reaction is become a step, is remarkably improved Atom economy, and by-product is hydrogen or water environmentally safe, thus be subject to the extensive concern of researcher。

Professor Hu Changwei of Sichuan University reports a kind of method being prepared aniline by the direct amination of benzene, the method is using ammonia as aminating agent, hydrogen peroxide is as oxidant, and the catalyst of use is Ni, Cu, Ce, V, Ti metallic catalyst (patent publication No.: CN101906045) that titanium-silicon molecular sieve TS-1 supports。Although the method reaction condition is gentle, environmental pollution is little, but carrier TS-1 is expensive, catalyst is relatively costly, and the yield of the Transform Law rate of benzene very low (lower than 10%), aniline is low。

Zhu Liangfang etc. are with γ-Al₂O₃For carrier, the catalyst made using two or three in nickel, molybdenum, vanadium, zirconium, manganese, cerium as active component is for (patent publication No.: CN1555921) in a step ammoxidation of benzene。This patent is also that hydrogen peroxide is as oxidant using ammonia as aminating agent, although reaction condition is gentle, but the yield of aniline is only 0.038%, and catalyst needs multistage roasting, preparation process more complicated, needs hydrogen reducing to activate before use。In addition, in order to solve using ammonia as the low restriction of aminating agent aniline yield rate, this seminar proposes with solubility vanadic salts (vanadium oxysulfate, ammonium metavanadate, sodium metavanadate) for catalyst in patent 200510020505, and oxammonium hydrochloride. is as aminating agent method of one-step synthesis aniline in aqueous acetic acid。The method makes the yield of aniline reach 68%, although the method substantially increases the yield of aniline, but soluble vanadium salt catalyst is expensive, can not recycle and reuse, relatively costly, thus also limit the commercial Application of the method。

Carbon Materials has the high specific surface area of comparison and big pore volume and higher hydrothermal stability and anti acid alkali performance energy due to it, is all widely used at field tools such as fuel cell, sensor, adsorbing separation, catalysis。Biomass are to there is material the most widely on the earth, prepare Carbon Materials not only Cheap highly effective, simple but also environmental sound with biomass for precursor, therefore become the focus of Recent study。Additionally, up to the present, vanadium dioxide that Carbon Materials supports, molybdenum dioxide catalyst react the application in the reaction of one-step method aniline in benzene and hydroxylamine salt it is not yet reported that。

Summary of the invention

It is an object of the invention to provide a kind of benzene and react, with hydroxylamine salt, the method directly preparing aniline, the method uses the vanadium dioxide catalyst that a kind of Carbon Materials supports, catalysis benzene and hydroxylamine salt can react the prepared aniline of a step and there is significantly high selectivity and reactivity under gentle reaction condition, simultaneously, this method for preparing catalyst process is simply, easily operate, with low cost。

The technical solution used in the present invention is:

A kind of benzene and hydroxylamine salt react the method for directly aniline processed, and the method comprises the steps:

Being separately added into acetic acid, water, hydroxylamine salt, benzene and catalyst in the normal pressure reactor with condensation reflux unit, be warming up to 70-80 DEG C, stirring the lower response time is 2-5h, obtains aniline；

Wherein, volume ratio is acetic acid: water: benzene=5:5:1, and quality is than benzene: catalyst=5～20:1, mol ratio benzene: hydroxylamine salt=1:1, and described catalyst is that the vanadium dioxide catalyst that Carbon Materials supports (is called for short VO₂/ C), active component VO in this catalyst₂Account for the 3～25% of catalyst gross mass。

Described hydroxylamine salt is oxammonium hydrochloride. or oxammonium sulfate.。

The preparation method of the vanadium dioxide catalyst that a kind of Carbon Materials supports, comprises the steps

Ammonium metavanadate and sucrose are joined in deionized water, solution is poured into water heating kettle after dissolving, in 80-180 DEG C of heat treatment 6-48 hour after airtight, eventually pass filter, hot wash obtains sepia solid to washing liquid is neutral, dried, and this solid 3-8 hour final black charcoal that obtains of 500-900 DEG C of carbonization in a nitrogen atmosphere carries vanadium dioxide catalyst (VO₂/ C)；

Wherein, material proportion is mol ratio ammonium metavanadate: sucrose=1:1～15, adds 1.3～19.9mmol ammonium metavanadate in every 60 ml deionized water。

The invention have the advantages that: the reaction that catalyst of the present invention reacts one-step method aniline for benzene and hydroxylamine salt has significantly high selectivity and reactivity, the selectivity of aniline is up to 99%, yield is up to 41%, compared with the good soluble vanadium salt catalyst of the catalytic performance of bibliographical information, solid catalyst provided by the invention is prone to and the separating of product after the completion of reaction, and catalyst is performing centrifugal separation on rear reusable, there is good application prospect。Compared with the traditional preparation methods infusion process of loaded catalyst, the preparation method of catalyst involved in the present invention adopts the method for Hydrothermal Synthesis, aqueous sucrose solution is mixed with metal precursor the precursor simultaneously obtaining carrier and active component through a step hydrothermal treatment consists, the content of catalyst activity component can be regulated by the concentration of modulation metal precursor, and the precursor that the preparation of catalyst is using abundant biomass resource sucrose as high-area carbon, other catalyst need not be additionally used to carry out the hydrolytie polycondensation of catalysing sucrose, with low cost, environmental friendliness and preparation process are simple, easily operation, there are good application and industrialization prospect。

Accompanying drawing explanation

Fig. 1 is the XRD spectra that the embodiment of the present invention 1 prepares catalyst。

Detailed description of the invention

Below in conjunction with specific embodiment, the invention will be further described, but the present invention is not limited to following example。

Embodiment 1

VO₂The preparation of/C-1# catalyst: 1.0g (8.5mmol) ammonium metavanadate and 6.8g (19.9mmol) sucrose are dissolved in 60mL deionized water, pour solution into water heating kettle until completely dissolved, in 120 DEG C of heat treatments 12 hours after airtight, after being down to room temperature through filtering, hot wash to washing liquid neutral, dried brown catalyst precarsor。By final for the 550 DEG C of carbonizations 6 hours in a nitrogen atmosphere of this catalyst precarsor black solid, from the XRD spectra of Fig. 1, except the steamed bread peak of unformed charcoal, other characteristic diffraction peaks and reference material VO₂(PDF 01-073-2362) coincide, and therefore gained catalyst activity component is VO₂。Catalyst is carried out thermogravimetric (TG) by SeteramSetsys16/18 thermal analyzer analyze, be computed VO in known prepared catalyst₂Account for the 15% of catalyst gross mass。

Embodiment 2

VO₂The preparation of/C-2# catalyst: preparation process is identical with embodiment 1, is different in that the amount of added ammonium metavanadate is 0.39g (3.3mmol), obtains VO in catalyst through thermogravimetric (TG) analytical calculation₂Account for the 4% of catalyst gross mass。

Embodiment 3

VO₂The preparation of/C-3# catalyst: preparation process is identical with embodiment 1, is different in that the amount of added ammonium metavanadate is 0.60g (5.1mmol), obtains VO in catalyst through thermogravimetric (TG) analytical calculation₂Account for the 6% of catalyst gross mass。

Embodiment 4

VO₂The preparation of/C-4# catalyst: preparation process is identical with embodiment 1, is different in that the amount of added ammonium metavanadate is 2.0g (17.1mmol), obtains VO in catalyst through thermogravimetric (TG) analytical calculation₂Account for the 20% of catalyst gross mass。

Embodiment 5

Benzene and oxammonium hydrochloride. react the reaction of directly aniline processed: add 5mL acetic acid and 5mL water in the 100mL there-necked flask equipped with stirring and condensation reflux unit, it is subsequently added 0.78g (11.25mmol) oxammonium hydrochloride., stir to being completely dissolved at 30 DEG C, be sequentially added into 0.1gVO₂/ C-1# catalyst and 1mL (11.25mmol, 0.89g) benzene, be warming up to 80 DEG C afterwards and react 4 hours。Reaction is down to room temperature after terminating, and uses in the NaOH solution of 30wt% and reactant liquor is to its PH=7～8, extract organic facies with 5mL ether, carry out qualitative analysis by gas chromatogram, carry out quantitative analysis with area normalization method after catalyst centrifugation。

Embodiment 6

Concrete course of reaction is identical with embodiment 5, is different in that used catalyst is VO₂/ C-2# catalyst。

Embodiment 7

Concrete course of reaction is identical with embodiment 5, is different in that used catalyst is VO₂/ C-3# catalyst。

Embodiment 8

Concrete course of reaction is identical with embodiment 5, is different in that used catalyst is VO₂/ C-4# catalyst。

Embodiment 9

VO₂The reusability of/C-1# catalyst: course of reaction is identical with embodiment 5, is different in that used catalyst is the VO reclaimed after embodiment 5 reaction₂/ C-1# catalyst。

Embodiment 10

Benzene and oxammonium sulfate. react the reaction of directly aniline processed: specifically course of reaction and material proportion and embodiment 5 are identical, are different in that hydroxylamine salt used is oxammonium sulfate.。

Table 1 is the reaction result of embodiment of the present invention 5-10。

Unaccomplished matter of the present invention is known technology。

Claims

1. the method that benzene and hydroxylamine salt react directly aniline processed, is characterized by that the method comprises the steps:

Wherein, volume ratio is acetic acid: water: benzene=5:5:1, and quality is than benzene: catalyst=5 ~ 20:1, mol ratio benzene: hydroxylamine salt=1:1, and described catalyst is the vanadium dioxide catalyst that Carbon Materials supports, active component VO in this catalyst₂Account for the 3 ~ 25% of catalyst gross mass；

The preparation method of the vanadium dioxide catalyst that described Carbon Materials supports, comprises the steps:

Ammonium metavanadate and sucrose are joined in deionized water, solution is poured into water heating kettle after dissolving, in 80-180 DEG C of heat treatment 6-48 hour after airtight, eventually pass filter, hot wash to washing liquid neutral, dried sepia solid, 500-900 DEG C of carbonization 3-8 hour in a nitrogen atmosphere of this solid final the vanadium dioxide catalyst that supports of black Carbon Materials；

Wherein, material proportion is mol ratio ammonium metavanadate: sucrose=1:1 ~ 15, adds 1.3 ~ 19.9mmol ammonium metavanadate in every 60 ml deionized water。

2. the method that benzene as claimed in claim 1 reacts directly aniline processed with hydroxylamine salt, is characterized by that described hydroxylamine salt is oxammonium hydrochloride. or oxammonium sulfate.。