Summary of the invention
The objective of the invention is to avoid above-mentioned weak point of the prior art, and a kind of feed stock conversion height is provided, separation efficiency is good, low equipment investment, long service life, a kind of preparation method who is applicable to the raw acetic acid methyl esters of oxo process diacetyl oxide device that comprehensive energy consumption is low.
Purpose of the present invention can reach by following measure:
The preparation method of methyl acetate of the present invention, be applicable to supporting method for preparing raw material as oxo process diacetyl oxide device, it is characterized in that with methyl alcohol and acetate be raw material, catalyzer, entrainer exist down, employing is provided with preheater 2, esterifying kettle 3 and the rectifying tower 5 that funnel-shaped tower tray 6 is housed, and the esterification rectifying operating system that is composited of two-chamber overflow phase splitter 13; Design preheater 2 bottom feeds, esterifying kettle 2 tops drip catalyzer, rectifying tower 5 top extraction product methyl acetates, side line extraction and phase-splitting, discharge the processing method of the water of esterification generation, and technological process comprises following operation steps:
1. continuously feeding, the preheating esterification
At first, in esterifying kettle 3, add the good bed material of forming by acetate, catalyzer, entrainer, the material benzenemethanol of adding is through material benzenemethanol feeding line 1, raw acetic acid is through raw acetic acid feeding line 19, and from the material of rectifying tower 5 tower stills, through rectifying tower still feed liquid circulation line 11 according to process requirements, enter the bottom of preheater 2 according to a certain percentage continuously, after the preheating, send into esterifying kettle 3 through its overhead line, catalyzer adds pipeline 4 through catalyzer and adds from the esterifying kettle top, carries out esterification in esterifying kettle, and its processing condition control is as follows:
Preheating temperature ℃ 100~105
Esterifying kettle temperature ℃ 90~120;
2. rectifying, rectifying tower top extraction methyl acetate
Enter through the downside of outlet line 20 from esterifying kettle 3 top effluent airs from rectifying tower 5, the rectifying tower top temperature control is at 56~57 ℃, overhead fraction is after condenser 7 condensations, enter return tank 8, wherein a part realizes refluxing through reflux pipeline A9 as the top of tower phegma of rectifying tower 5, and another part is through 10 extraction of product extraction pipeline, send into the methyl acetate pan tank, standby;
3. the side line extraction separates, and discharges the water that esterification generates
Side line extraction cut temperature is controlled between 75~90 ℃, from the effluent in the dark weir of the funnel-shaped tower tray 6 at rectifying tower 5 middle parts, after condenser B 12 further condensations, enter phase-splitting chamber 16 phase-splittings of two-chamber overflow phase splitter 13, upper organic phase is crossed dividing plate 14, overflow to back cavity 15, the position below the funnel-shaped tower tray 6 at rectifying tower 5 middle parts is arrived in reflux pipeline B 17 total refluxs enters rectifying tower; Participate in rectifying separation;
Phase-splitting chamber 16 lower aqueous layer are gone to recovery system through water vent line 18, reclaim wherein useful composition;
4. the whole recycles of rectifying tower bottoms
The still liquid of rectifying still 5 through the bottom of rectifying tower still feed liquid circulation line 11 inflow preheaters 2, continues to participate in esterification.
Purpose of the present invention can also reach by following measure, is the disclosed optimized technical scheme of contriver below:
The preparation method of methyl acetate of the present invention, the theoretical plate number of its described rectifying tower 5 are 30~50.
The preparation method of methyl acetate of the present invention, described catalyst for esterification reaction is sulfuric acid or tosic acid.
The preparation method of methyl acetate of the present invention, described catalyst for esterification reaction is a tosic acid, its consumption is 0.1~10% of a reaction mixture total amount.
The preparation method of methyl acetate of the present invention, described catalyst for esterification reaction is a tosic acid, its consumption is 2~6% of a reaction mixture total amount.
The preparation method of methyl acetate of the present invention, described material benzenemethanol and second
The ratio of adding of acid is to wait mole.
The preparation method of methyl acetate of the present invention, the trim the top of column of described rectifying tower 5 is than moisture content shared weight ratio≤3% in total reaction material amount that keeps in the esterifying kettle 2.
The preparation method of methyl acetate of the present invention, described entrainer is any one that chooses from toluene, diisobutyl ether, n-butyl acetate, isobutyl acetate, methyl iso-butyl ketone (MIBK).
The preparation method of methyl acetate of the present invention, described entrainer is a n-butyl acetate.
The preparation method of methyl acetate of the present invention, described esterifying kettle 2 is glassed steel reaction vessels, and the 316L stainless steel is adopted in the bottom of the funnel-shaped tower tray 6 of rectifying tower, and the 304L stainless steel is adopted on the top of the funnel-shaped tower tray 6 of rectifying tower.
The preparation method of methyl acetate disclosed by the invention has following positively effect compared to existing technology:
1. a kind of feed stock conversion height is provided, and separation efficiency is good, low equipment investment, long service life, a kind of preparation method who is applicable to the raw acetic acid methyl esters of oxo process diacetyl oxide device that comprehensive energy consumption is low.
2. the esterifying catalyst vitriol oil directly is added in the esterification enamel still, solved the etching problem of rectifying tower, rectifying tower only needs 316L and 304L stainless steel to get final product, compare with the C-276 or the extraordinary steel lining of liner C-276 of available technology adopting, equipment cost can be saved 2,000,000 yuans of investments.
3. rectifying Tata still material without cooling, directly recycles, and acetate formic acid per ton is saved 1t low-pressure steam, 50KWh.
4. Zhi Bei methyl acetate is fit to the use of oxo process diacetyl oxide device.
Embodiment
The present invention is described in further detail below in conjunction with embodiment:
Embodiment 1
According to preparation method of the present invention and step, preparation is applicable to the raw acetic acid methyl esters of oxo process diacetyl oxide device
1. continuously feeding, the preheating esterification
At first, add the good bed material of being made up of acetate, n-butyl acetate, sulfuric acid in esterifying kettle 3, the material benzenemethanol of adding is through material benzenemethanol feeding line 1, flow 0.76m
3/ hour, raw acetic acid is through raw acetic acid feeding line 19, flow 1m
3/ hour, and from the material of rectifying tower 5 tower stills, through rectifying tower still feed liquid circulation line 11 according to process requirements, enter the bottom of preheater 2 according to a certain percentage continuously, after the preheating, send into esterifying kettle 3 through its overhead line, catalyzer adds pipeline 4 through catalyzer and adds from the esterifying kettle top, carry out esterification in esterifying kettle, its processing condition control is as follows:
Preheating temperature ℃ 103
Esterifying kettle temperature ℃ 90;
2. rectifying, rectifying tower top extraction methyl acetate
Enter through the downside of outlet line 20 from esterifying kettle 3 top effluent airs from rectifying tower 5, the rectifying tower top temperature control is at 56 ℃, overhead fraction is after condenser 7 condensations, enter return tank 8, wherein a part is as the top of tower phegma of rectifying tower 5, realize refluxing through reflux pipeline A 9, another part is through 10 extraction of product extraction pipeline, 1.5m
3/ hour send into the methyl acetate pan tank, standby;
3. the side line extraction separates, and discharges the water that esterification generates
Side line extraction cut temperature is controlled between 78 ℃, from the effluent in the dark weir of the funnel-shaped tower tray 6 at rectifying tower 5 middle parts, after condenser B 12 further condensations, enter phase-splitting chamber 16 phase-splittings of two-chamber overflow phase splitter 13, upper organic phase is crossed dividing plate 14, overflow to back cavity 15, the position below the funnel-shaped tower tray 6 at rectifying tower 5 middle parts is arrived in reflux pipeline B 17 total refluxs enters rectifying tower; Participate in rectifying separation;
Phase-splitting chamber 16 lower aqueous layer are gone to recovery system through water vent line 18, reclaim wherein useful composition;
4. the whole recycles of rectifying tower bottoms
The still liquid of rectifying still (5) through the bottom of rectifying tower still feed liquid circulation line 11 inflow preheaters 2, continues to participate in esterification.
Embodiment 2
According to method and the step of embodiment 1, difference only is
1. catalyzer adopts tosic acid.
2. advance acetic acid 2m
3/ hour; Methyl alcohol 1.5m
3/ hour, the control preheating temperature is 100 ℃, heats up 90 ℃ of esterification temperatures with low-pressure steam.
3. rectifying tower middle part cut extraction temperature is 75 ℃,
4. the rectifying tower top temperature is 57 ℃, extraction methyl acetate 3.2m
3/ hour.