工業氣相合成異戊烯醇簡述
異戊烯醇,3甲基-3丁基-1醇,CAS No.763-32-6, 是一種萜醇主要用于加工聚羧酸水泥減水劑的基本原料。
異戊烯醇是依普林斯反應將醛類及烯類高壓,氣相加成合成生成。顯著不同于市場其他異戊烯醇生產工藝。
氣相合成工藝與國際市場其他溶液,溶劑及催化劑工藝比較
1.溶液法工藝:
早在1970年,飛利浦公司使用甲醛溶液和甲醇生產異戊烯醇。甲醇和甲醛摩爾比為10:1;反應溫度:275℃-300℃;壓力138Kg/cm2.異戊烯醇收率80%。該工藝缺點:產品中雜質多,副產品多;高溫;高壓。
2.使用有機溶劑苯合成異戊烯醇工藝:
異丁烯和甲醛摩爾比大于11:1;溫度200℃;批次反應反應時間6小時。異戊烯醇收率:85%。該工藝缺點:產品純度低,反應收率低。
3. BASF工藝:
50%水溶多聚甲醛,氮氣加壓至250Kg/cm2;溫度:250℃,異丁烯和甲醛摩爾比為10:1;批次操作反應時間:1小時。異戊烯醇收率達96%。該工藝缺點:生成大量污水;高溫高壓。工業化和投資均不可行。
4. 催化劑選擇合成工藝:
非均質催化劑:
催化劑采用金屬羰基化合物,甲醛或聚甲醛溶在有機溶劑中;溫度:200℃;反應周期1小時。該工藝缺點:在使用WO3金屬氧化物為催化劑,甲醛轉化率70%。問題是該種催化劑對異戊烯醇選擇性較低
均質催化劑:
結合到離子交換樹脂的金屬氯化物Sncl和Zncl. 反應條件溫和,溫度<100℃,常壓,但收率低。盡管在水溶液狀態下可提高催化劑活性,異戊烯醇的選擇性低。
Sncl和Zncl 結合到離子交換樹脂上。可以獲得四烷基銨,鋅,硅和沸石復合物例如,催化劑ZSM-5 和FeMCM-22. 異戊烯醇合成的選擇性低,選擇性低,收率低。
催化反應另一個問題是異戊烯醇由催化劑中及由未反應物中分離困難。工藝收率低,反應選擇性低。催化劑昂貴。
氣相合成工藝特色
1.因氣相合成工藝無溶劑,無水溶液,無催化劑,不存在異戊烯醇由溶劑或由催化劑中分離操作,獲得無污染、高純度的異戊烯醇。因無催化劑,避免異戊烯醇由催化劑中分離;不使用昂貴催化劑大大降低工藝成本。
2.原料在市場上普遍,易得。
工藝原料及化學品:
(1) 多聚甲醛
(2) 異丁烯
(3) 苛性鈉
3.生產操作簡。工藝中僅兩個控制參數:溫度,壓力;連續化工藝,連續回收未反應物,優化了反應物消耗。
4.異戊烯醇的轉換率高
對多聚甲醛收率為97%,對異丁烯收率為90%
5.無污染物排放
工藝中無催化劑,無溶劑,無三廢污染物排放是綠色環保工藝
6.占地小(裝置總占地:1萬平方米)
7. .裝置簡單,設備少(裝置中反應器,泵,塔,換熱器,儲罐…總計124臺)。
8.投資少
由于原料在市場上易得,連續化工藝簡單,設備臺數少及環保無三廢排放裝置總投資少
9.異戊烯醇產品標準:
純度:>98%
水分: <0.1%
使用該技術的裝置運行多年實踐證明裝置安全可靠沒有任何工藝,設備事故。產品質量穩定始終達到國際標準。
異戊烯醇技術及工業化裝置獲得國家發明專利 CN 112430178 A .具有自主知識產權。
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Description for Industrially Synthetic Isoprenol Process
in Gas-phase
I soprenol, 3-methyl-3-buten-1-ol, CAS No. 763-32-6, is a kind of Terpene alcohol, mainly using primary material to process polycarboxylic acid cement water-reducing additive. Isoprenol is synthesized by aldehydes and olefins under high pressure in gas phase, called as Prins Reaction. It is quite different with other process in Market.
Comparative between gas-phase process and solvent, solution and catalytic process in the international market
1. Synthesize isoprenol in solution process
In the end of 1970 Phillips Petroleum Company synthesized isoprenol by using formaldehyde in aqueous solution and solution with methanol. Methanol in a molar relationship 10 times bigger to FA, to 275-300°C and 1,38*107Pa with a ISP yield of 80%. Disadvantages were for the product purity and for the pressure and operating temperature conditions of the process also high, as well as many by-products.
2.Synthesize isoprenol by using organic solvents like benzene:The use of organic solvents, like for example the benzene, allows to realize the process, with ISB in a molar relationship as regards the FA of 11:1, at 200°C for 6 hours with a yield in ISP of 85%. The use of organic solvents brings some disadvantages for the product purity and the reaction yield low.
3. Synthesize isoprenol by BASF
The aqueous PFA used at 50% and the use of nitrogen to pressurize till a total pressure of 2,5*107Pa. The reaction takes place at 250°C with a molar relationship ISB:FA of 10:1 and with 1 hour of residence time.
The yield in ISP is 96%, the major part of the sewage to be treated around 10 times more than the current process as well as the high pressure and temperature in the process.
The difficult operating conditions (high temperature and pressure), don’t allow to the process to get importance from an industrial and financial point of view.
4. The process for selective synthesis of catalyst:
Catalyst in Heterogeneous:
Metallic carbonyls and oxides were selected to use of FA or PFA solutions in organic solvents at a temperature of 200°C for one hour. With these catalytic systems it obtained low yields of ISP (till 70% of FA conversion, with catalyst based on WO3). The problem in this system was the scarce selectivity to ISP synthesis reaction.
Catalyst in homogeneous:
The use of Catalyst in homogeneous like the metallic chlorides (for example SnCl4 and ZnCl2) bound to a resin with ionic exchange with soft conditions (temperatures <100°C and room pressure) brings to low yields, especially in presence of water. In anhydrous conditions, these catalytic systems have a higher activity but a low ISP selectivity.
The use of SnCl4,ZnCl2 bound to a resin with ionic exchange has been experimented and it contains Tetraalkylammonium, complexes of tin, silica and zeolite like ZSM-5 and FeMCM-22. Also in this case the scarce selectivity of the catalysts for the ISP synthesis, brings to a scarce process yield.
The above mentioned catalytic processes show some inconveniences bound to the separation of the ISP from the other reaction mixture components. In particular the reaction mixture,including catalyst is hardly separable. It was together with the scarce processes yield due to the low reaction selectivity, making the processes expensive and not so exploitable.
Characteristics for synthesis process in gas-phase
1.As are no solvent, catalysts and water in gas-phase process it does not need to separate isoprenol from solvent, catalyst or water so that it can obtain isoprenol with high purity and no pollution.
As no catalyst existed in process separation between isoprenol and catalyst does not need. The cost of process is tremendously reduced because there is no catalyst application.
2. The raw materials are easy to find and to procure in the market
Raw materials and chemicals in process
(1)Paraformaldehyde
(2)Isobutene
(3)Caustic soda
3. Production process is very simple. In process there are only two parameters such as temperature and pressure to be controlled, continuous process, continuous recovery for un- reacted materials, optimizing the consumption of reaction materials.
4.Selectivity high for isoprenol
97% yield to Paraformaldehyde and 90% to Isobutene
5. No pollution discharged from plant
There is no catalyst, no solvent, no solid wastes discharged from process, protecting environment.
6.Small land occupation (plant area: ten thousand square meters)
7.The plant composed is also simple with less equipment installed (reactors, pumps, towers, heat exchangers and tanks…total 124 sets)
8. Investment less
As the raw materials are easy to procure in the market and continuous process is simple and number of equipment installed is less and no pollution discharged from plant so total investment in plant is also extremely reduced.
9.Specification of isoprenol product
Purity: >98%
Water: <0.1%
Operation practice strong demonstrated that the plant is safety, reliable, without any accidents occurred in process and equipment. The quality of product always is stable, reaching the international standard
The technology of isoprenol and its industrial plant also obtained an invention patent in State CN 112430178 A, having independent intellectual property rights.