Synthesis method for highly selective 2-methylallyl chloride and synthesis reactor thereof

Abstract

The present invention relates to a synthesis method and synthesis reactor of high-selectivity 2-methylallyl chloride by taking isobutylene and chlorine gas as raw materials and performing a gas-phase chlorination reaction in a microchannel reactor with a cooling surface. The isobutylene and the chlorine gas are reacted in a T-shaped microchannel reactor, and the mixing speed is extremely fast. Meanwhile, the huge heat exchange area per unit volume can ensure that the reaction proceeds stably at a substantially constant temperature and has good controllability. Therefore, side reactions caused by excessive local temperature can be effectively suppressed, the reaction selectivity is high, and no coking phenomenon occurs.

Claims

1. A synthesis reactor assembly for producing high-selectivity 2-methyl-3-chloroallyl, comprising: an isobutylene supply having isobutylene; a chlorine gas supply having chlorine gas; a plurality of synthesis reactors arranged side-by-side, each synthesis reactor comprising: a synthesis reaction tube fluidly coupled with an isobutylene inlet tube configured to receive the isobutylene from the isobutylene supply and fluidly coupled with a chlorine gas inlet tube configured to receive chlorine gas from the chlorine gas supply; wherein the isobutylene inlet tube, the chlorine gas inlet tube, and the synthesis reaction tube are connected in tee form; wherein the isobutylene inlet tube and the chlorine gas inlet tube are in a U-shape, and an upper end of the synthesis reaction tube is connected to the U-shape to form the tee form; and wherein the isobutylene inlet tube, the chlorine gas inlet tube, and the synthesis reaction tube have a diameter of 0.2-0.5 mm, respectively; a cooling jacket wrapped around the plurality of synthesis reactors arranged side-by-side; and a cooling surface of each synthesis reactor has a heat exchange area of 8000-20000 m.sup.2/m.sup.3 based on an actual reaction volume of each synthesis reactor.

2. The synthesis reactor assembly for producing high-selectivity 2-methyl-3-chloroallyl of claim 1, comprising: isobutylene in each isobutylene inlet tube; and chlorine gas in each chlorine gas inlet tube.

3. A method for synthesizing high-selectivity 2-methyl-3-chloroallyl, comprising: providing the synthesis reactor assembly of claim 1; feeding isobutylene from the isobutylene supply through each isobutylene inlet tube and chlorine gas from the chlorine gas supply through each chlorine gas inlet tube; mixing the isobutylene and the chlorine gas at each tee form to produce a mixture of isobutylene and chlorine gas; and performing a gas-phase chlorination reaction of the mixture of isobutylene and chlorine gas in each synthesis reaction tube to produce 2-methyl-3-chloroallyl.

4. The method according to claim 3, wherein an excess amount of isobutylene is added in the chlorination reaction.

5. The method according to claim 4, wherein a molar ratio of the isobutylene to the chlorine gas is 1.005˜1.02:1.

6. The method according to claim 3, wherein the chlorination reaction temperature is 0˜30° C. and the chlorination reaction residence time is 0.1˜1 second.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic structural diagram of a synthesis reactor according to the present invention; and

(2) FIG. 2 is a schematic structural diagram of a synthesis reactor assembly of the present invention.

(3) Reference symbols represent the following components: 1-cooling jacket; 2-chlorine gas inlet tube; 3-isobutylene inlet tube; 4-reaction tube; 5-reaction product outlet tube.

DETAILED DESCRIPTION

(4) The technical solution of the present invention is further described below with reference to the drawings and examples.

(5) As shown in FIG. 1, the present invention relates to a synthesis reactor with a cooling jacket 1. The reactor is an elongated reaction tube 4. A raw chlorine gas inlet tube 2 and an isobutylene inlet tube 3 are connected to an upper port of the reaction tube 4, and a reaction product outlet tube 5 is connected to a lower port of the reaction tube 4. According to the present invention, the chlorine gas inlet tube 2, the isobutylene inlet tube 3 and the reaction tube 4 are connected (e.g., connected in a tee shape) just by ensuring that the two raw materials enter the one end of the reaction tube 4 at the same time for a mixed reaction. A product outlet is formed in the other end of the reaction tube 4. Preferably, the chlorine gas inlet tube 2, the isobutylene inlet tube 3 and the reaction tube 4 are T-shaped or Y-shaped.

(6) As shown in FIG. 2, a plurality of synthesis reactors of the present invention are connected in a combined manner. Each reactor is an independent reaction tube 4, with an independent chlorine gas inlet tube 2, isobutene inlet tube 3 and reaction product outlet tube 5. A plurality of reactors share the same cooling jacket 1, which is equivalent that a plurality of synthesis reactors of the present invention are fixed side by side in the same cooling jacket, thereby effectively using the space and energy, and improving the reaction efficiency.

EXAMPLE 1

(7) Isobutene and chlorine gas are introduced respectively into the microchannel reactor shown in FIG. 1 (the channel diameter is 0.2 mm, and the heat exchange area calculated based on the actual reaction volume is 20000 m.sup.2/m.sup.3). By adjusting and controlling the flows of isobutene and chlorine gas, the reaction residence time reaches 1 second. A molar ratio of the isobutylene to the chlorine gas is 1.005:1, and the reaction temperature is controlled to 0° C. by freezed brine. After 30 minutes of stable operation, a liquid product is sampled from an outlet of the reactor, and the composition of the liquid product is analyzed as the following mass content: 89.6% of 2-methylallyl chloride, 2.3% of chloro-tert-butane, 1.3% of isobutenyl chloride, 5.6% of dichloro-tert-butane, and 1.2% of dichloro-isobutene. Therefore, the selectivity of the calculated 2-methylallyl chloride is calculated as 91.4%.

EXAMPLE 2

(8) Isobutene and chlorine gas are introduced respectively into the microchannel reactor shown in FIG. 1 (the channel diameter is 0.5 mm, and the heat exchange area calculated based on the actual reaction volume is 8000 m.sup.2/m.sup.3). By adjusting and controlling the flows of isobutene and chlorine gas, the reaction residence time reaches 0.1 second. A molar ratio of the isobutylene to the chlorine gas is 1.02:1, and the reaction temperature is controlled to 30° C. by low-temperature water. After 30 minutes of stable operation, a liquid product is sampled from the outlet of the reactor, and the composition of the liquid product is analyzed as the following mass content: 88.7% of 2-methylallyl chloride, 2.1% of chloro-tert-butane, 1.5% of isobutenyl chloride, 6.0% of dichloro-tert-butane, and 1.5% of dichloro-isobutene. Therefore, the selectivity of the calculated 2-methylallyl chloride is calculated as 90.5%.

EXAMPLE 3

(9) Isobutene and chlorine gas are introduced respectively into the microchannel reactor shown in FIG. 1 (the channel diameter is 0.4 mm, and the heat exchange area calculated based on the actual reaction volume is 10000 m.sup.2/m.sup.3). By adjusting and controlling the flows of isobutene and chlorine gas, the reaction residence time reaches 0.5 second. A molar ratio of the isobutylene to the chlorine gas is 1.01:1, and the reaction temperature is controlled to 10° C. by freezed brine. After 30 minutes of stable operation, a liquid product is sampled from the outlet of the reactor, and the composition of the liquid product is analyzed as the following mass content: 89.3% of 2-methylallyl chloride, 2.3% of chloro-tert-butane, 1.4% of isobutenyl chloride, 5.7% of dichloro-tert-butane, and 1.3% of dichloro-isobutene. Therefore, the selectivity of the calculated 2-methylallyl chloride is calculated as 91.1%.

EXAMPLE 4

(10) Isobutene and chlorine gas are introduced respectively into the microchannel reactor shown in FIG. 2 (the channel diameter is 0.3 mm, and the heat exchange area calculated based on the actual reaction volume is 13330 m.sup.2/m.sup.3). By adjusting and controlling the flows of isobutene and chlorine gas, the reaction residence time reaches 0.3 second. A molar ratio of the isobutylene to the chlorine gas is 1.01:1, and the reaction temperature is controlled to 20° C. with low-temperature water. After 30 minutes of stable operation, a liquid product is sampled from the outlet of the reactor, and the composition of the liquid product is analyzed as the following mass content: 89.1% of 2-methylallyl chloride, 2.2% of chloro-tert-butane, 1.5% of isobutenyl chloride, 5.8% of dichloro-tert-butane, and 1.4% of dichloro-isobutene. Therefore, the selectivity of the calculated 2-methylallyl chloride is calculated as 90.9%.