transporting alkylbenzene into a catalyst synthesis reactor; mixing a carrier inorganic substance and an alkali metal catalyst uniformly to obtain a raw material A; using an alkene as a raw material B;

synthesizing a catalyst in the catalyst synthesis reactor using the raw material A, and transporting the catalyst and the alkylbenzene simultaneously into an alkylbenzene preheater to allow preheating;

preheating the raw material B in an alkene preheater;

mixing an obtained preheated raw material A and an obtained preheated raw material B in a gas-liquid mixer to obtain a mixed solution;

transporting the mixed solution as a reaction system into a double-chamber coil reactor to allow a continuous reaction to obtain an ibuprofen raw material;

cooling the reaction system after the continuous reaction is completed, separating unreacted alkene after the cooling is completed to obtain a remaining part, and recycling cooled alkene to allow secondary utilization; separating and recycling a solid catalyst from the remaining part to obtain a remaining reaction liquid, and introducing the remaining reaction liquid and a quencher into a quenching tank to allow quenching; and

subjecting a system obtained after the quenching to continuous extraction with water as an extractant to transfer impurities into an aqueous phase, and separating remaining alkylbenzene and ibuprofen raw material by extraction with dimethyl sulfoxide (DMSO), wherein a separation yield is 85 wt %;

the catalyst synthesis reactor works at 80° C. to 200° C. and a pressure of 2 MPa to 5 MPa;

the alkylbenzene preheater works at 150° C. to 300° C. and a pressure of 5 MPa to 15 MPa;

the alkene preheater works at 150° C. to 300° C. and a pressure of 5 MPa to 15 MPa;

the mixed solution is subjected to the continuous reaction for 10 min;

the quencher is a 10 wt % NaOH aqueous solution;

the quenching is conducted at less than or equal to 30° C.; and

the cooled alkene is recycled for reutilization at 20° C.