The present invention refers to a production equipment for production of a caprolactone, such as ε-caprolactone, by reaction between peracetic acid and cyclohexanone in a so called Baeyer-Villiger reaction.

The first step in a caprolactone synthesis is typically the generation of peracetic acid, from acetic acid and hydrogen peroxide, used to oxidise cyclohexanone according to reaction scheme (I) below

Yielded peracetic acid reacts with cyclohexanone to yield caprolactone and acetic acid according to reaction scheme (II) below

The present invention is directed to a production equipment for production of a caprolactone by above disclosed reactions, said equipment is in embodiments split into a first section wherein peracetic acid is produced, a second section wherein caprolacton is produced, and a third section wherein yielded product is purified.

Said first section (Fig. 1) comprises, in embodiments of the present invention, a hydrogen peroxide inlet (1), a concentration unit (2) wherein hydrogen peroxide is concentrated into high strength hydrogen peroxide, a high strength hydrogen peroxide tank (3), a measure unit (4) wherein said high strength hydrogen peroxide and acetic acid are measured before being mixed and cooled in a premix unit (5), and peracetic acid stills (6) wherein said high strength hydrogen peroxide and said acetic acid is reacted in presence of a catalyst, such as sulphuric acid, and fractionated by distilling off yielded peracetic acid, unreacted acetic acid and water and holding back unreacted peroxide and catalyst,. Yielded peracetic acid is subsequently and after addition of a stabiliser, such as dipicolinic acid, sent to a storage tank for further feeding to said second section (Fig.2). Said concentration unit (2) comprises, in especially preferred embodiments of said first section (Fig. 1), a serious of 3 peroxide concentrators (2a, 2b and 2c) being for instance film evaporators having large surface areas. In likewise preferred embodiments said premix unit (5) comprises a series of 3 agitated vessels (5a, 5b and 5c). 60-70%, such as 70%, hydrogen peroxide is in said concentration unit (2), at a pressure of for instance 20-45 mBar and at a temperature of 50-60°C, such as 55 +/-2°C, concentrated into high strength peroxide comprising at least 80%, such as at least 85%, hydrogen peroxide. The peracetic acid stills (6) are in said preferred embodiments suitably operated at 70-150, such as 110-130, mBar and yielded peracetic acid has typically a peracetic acid concentration of 30-55%).

Said second section (Fig. 2) comprises, in preferred embodiments of the present invention, a peracetic acid inlet (7), a cyclohexanone inlet (8), a first reactor (9) and a second reactor (10), wherein said peracetic acid and said cyclohexanone is reacted, followed by a set of post- reaction tubular reactors (1 1), a product cooler (12), wherein yielded reaction mixture is cooled, and an outlet (13) for further feeding of yielded reaction mixture to said third section (Fig. 3). Said first reactor (9) and said second reactor (10) are, in especially preferred embodiments, made of glass and equipped with internal water cooled glass coils controlling reaction temperature and thus reaction rate. Said first reactor (9) comprises preferably a series of 4 reactor units (9a, 9b, 9c and 9d) while said second reactor (10) preferably comprises 2 reactor units (10a and 10b). Said set of post-reaction tubular reactors (1 1) is, in likewise preferred embodiments, water sprayed to control the reaction temperature. Said second section may in further preferred embodiments be equipped with a safety system, protecting against runaway reactions, dumping the reaction mixture.

Said third sector (Fig. 3) comprises, in preferred embodiments of the present invention, an inlet (14) for feeding of yielded reaction mixture, a pre-heater (15) heating the reaction mixture to a predetermined temperature, such as 50 +/- 5°C, a stripper (16) wherein water is removed, a fractionator (17) wherein light ends and unreacted raw materials are removed through an outlet (18). The fractionated product is fed to a tank (19) and subsequently to a thin film evaporator (20) via a pre-heater (21) and finally to a distillation column (22), operating at for instance 0.5-20, such as 5-10, mbar, comprising separation steps yielding purified caprolactone.

The production equipment according to the present invention may optionally and additionally comprise a forth section (Fig. 4) comprising a tank (23) comprising unreacted raw materials and light ends which products are separated in at least a primary (24), a secondary (25) and a tertiary (26) distillation column, whereby cyclohexanone and acetic acid are recovered and optionally recycled. Said primary distillation column (24) is, in preferred embodiments, operated at for instance atmospheric pressure, whereby an azeotrope of water and cyclohexanone is distilled off and separated in a decanter (27). Acetic acid is, in said secondary distillation column (25), which suitably operates at for instance a temperature of 1 10-120°C, distilled off and sent to a storage tank. Cyclohexanone is, under for instance vacuum condition, purified in said tertiary distillation column (26) and remains are sent for disposal.

While particular embodiments of the invention have been shown, it will be understood, of course, that the invention is not limited thereto since many modifications may be made, and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention. These and other objects will be more fully understood from appended drawings, wherein like reference numerals have been applied to like parts throughout the various figures and wherein:

Figur 1 : Schemes an embodiment of said first section of the claimed production equipment,

Figur 2: Schemes an embodiment of said second section of the claimed production equipment,

Figur 3 : Schemes an embodiment of said third section of the claimed production equipment, and,

Figur 4: Schemes an embodiment of said optional forth section of the claimed production

equipment.