Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Removing and recycling removed material from an ongoing...
Reexamination Certificate
1999-09-27
2001-11-20
Buttner, David J. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Removing and recycling removed material from an ongoing...
C526S068000, C528S417000, C528S421000, C568S608000, C568S618000, C568S620000, C422S131000, C422S132000, C422S134000, C422S138000
Reexamination Certificate
active
06319999
ABSTRACT:
The present invention relates to a new semi-continuous process and apparatus for the production of polyadducts of alkylene oxides by an addition reaction of alkylene oxide on a chain initiator which has at least one active hydrogen. These products, particularly the polyadducts of ethylene oxide and propylene oxide, are used mainly as non-ionic surfactants and polyrether-polyols.
Non-ionic surfactants are very widely used as wetting agents, dispersants, stabilisers, emulsifying agents and anti-emulsifying, anti-foaming and foaming agents and, in general, as auxiliary chemicals and functional fluids in the textile, paper, cellulose, pharmaceutical, food, cosmetic, paint, resin, mineral extraction and processing, advanced recovery and extraction of petroleum industries. In particular the use should be mentioned of non-ionic surfactants based on natural or synthetic fatty alcohols, as primary components in the formulation of household and industrial detergents and also of polyether-polyols as the main intermediates in the production of polyurethanes (rigid, semi-rigid, flexible foams, elastomers, adhesives, sealants, etc).
Italian Patent No. 1 226 405 describes a method for the production of polymerisation products of alkylene oxides starting from alkylene oxides, ethylene and/or propylene oxides being most commonly used, and compounds having an active or mobile hydrogen atom with suitable catalysts. The method of this patent uses a two-section reactor of which the upper is termed the gas-liquid reactor and the lower is an accumulation reservoir, disposed essentially horizontally. The gas-liquid reaction takes place in the upper section, the chain initiator being supplied from a plurality of spray heads on a central distributor while the lower body acts as a receiver and for recycling through a pump and an external heat exchanger, the reaction product coming from the upper section being resupplied to the latter to continue the polymerisation reaction.
Italian Patent No. 1 226 406 describes a method for obtaining polymerisation products of alkylene oxides which uses a two-section reactor of which the upper is termed the gas-liquid reactor and the lower is an accumulation reservoir, each section having a plurality of spray heads. The first phase of the reaction occurs in the lower section which is arranged vertically and continues until a given quantity of polymerisation product is formed; subsequently the polymerisation reaction is transferred to the upper section, arranged horizontally, where the reaction can continue until the desired product is obtained.
The processes described in the aforesaid patents, however, have several disadvantages. First of all they use two-section reactors which complicates the overall structure of the plant and increases costs; the two-section reactors also have a large-diameter communication aperture and, for Italian Patent 1 226 406, a larger number of apertures, thus increasing the possibility of loss of alkylene oxide and formation of dead zones and internal surfaces exposed to the oxide. As two-section internal distributors are provided, the surface-volume ratio of these reactors is higher, increasing the probability of secondary reactions. The double-bodied configuration and presence of internal distributors also creates dead spaces within the reactor which makes it difficult to drain and clean the reactor, thus increasing problems in changing production.
It should also be mentioned that the flow under gravity of the reaction product which collects in the upper horizontal section and is then ducted down into the lower one induces retrodiffusion and hence overexposure to the oxide atmosphere.
The problem at the root of the invention is thus to provide a process for the production of polyadducts of alkylene oxides which is able to overcome the problems of the prior art.
The problem is resolved., according to the invention, by a semi-continuous process for the production of polyadducts of alkylene oxides, by the addition reaction of alkylene oxide on a chain initiator which has at least one active hydrogen, characterised in that it includes the steps of:
providing a reactor constituted by a cylindrical body with two diameters, arranged with its longitudinal axis substantially vertical, with the upper part of the cylindrical body of a greater diameter than the lower part, and the reactor having inlet and outlet apertures, equipment for atomising the reaction mixture and equipment for atomising the alkylene oxide, the atomising equipment being located and arranged over the entire inner surface of the upper part of the reactor;
loading the reactor with a predetermined volume of liquid including the chain initiator;
discharging the liquid through the outlet aperture and bringing it to a predetermined reaction temperature by means of heat-exchange means;
atomising the liquid by means of the atomising equipment and introducing the alkylene oxide through the atomising equipment to obtain an intermediate liquid reaction product which forms a mixture with the liquid chain initiator;
recycling the mixture obtained continuously after it has been brought back to the predetermined reaction temperature, by atomising it in the upper part of the reactor by means of the atomising equipment and making it react with a further quantity of alkylene oxide in order to obtain a final product with the desired chain length.
The chain initiator is usually used in quantities equal to the ratio between the final quantity of the product and the growth ratio where the growth ratio is defined as the ratio between the molecular weight of the product and the molecular weight of the chain initiator.
The chain initiators which may be used are compounds having at least one active hydrogen according to the final product it is desired to obtain; examples of such chain initiators may be found among the alkylphenols, such as octylphenol, nonylphenol, dodecylphenol, dinonylphenol, tristyrylphenol; natural and synthetic fatty alcohols and mixtures thereof, such as decyl alcohol, tridecyl alcohol, oleyl alcohol, oleylacetyl alcohol, cetylstearyl alcohol, lanolin, cholesterol, acetylene diol; fatty amines and hydrogenated amines, such as laurylamine, oleylamine, amine derived from coconut oil, tallow amine and soya amine, soya iminopropylenamine, abietylamine; fatty amides, such as laurylamide, stearyl amide, fatty amides derived from coconut oil, soya and tallow; fatty acids such as coconut, lauric, tallow, stearic, palmitic, oleic, myristic, linoleic, abietic and naphthenic acids; sorbitan esters such as the monolaurate, monopalmitate, monostearate, mono-oleate, monoabietate, dilaurate, tristearate, trioleate, pentalaurate, hexaoleate, hexastearate; monoglycerides and monostearates of, for example, coconut and glycerol; pentaerythritol esters, such as the monolaurate, mono-oleate and of lanolin; ethylene glycols, such as mono-, di-, tri-ethylene glycols and polyethylene glycols; propylene glycols, such as mono-, di-, tri-propylene glycols and polypropylene glycols; ethylene oxide/propylene oxide block polymers and random sequences thereof based on various chain initiators, such as fatty amines, fatty alcohols, glycerol, dipropylene glycol etc; oils such as castor-oil, hydrogenated castor-oil, mink oil, tallow and tall oil; mercaptans such as dodecyl mercaptan.
In order to activate the alkoxylation reaction, to speed it up and, whenever necessary, a catalyst is introduced into the reactor which must disperse completely in the chain initiator to give rise to the reaction of the alcoholate in situ.
A particularly preferred embodiment of the invention provides for the use of a basic catalyst which is selected from the group comprising hydroxides and alcoholates of alkali metals and hydroxides of alkaline-earth metals. Acidic catalysts may however also be used even though they are not preferred since they have the disadvantage of increasing the concentration of dioxan in the product. The catalyst may be added either in the solid phase or in aqueous solution and is introduced directly into the ex
Buttner David J.
Linde Aktiengesellschaft
Millen White Zelano & Branigan P.C.
LandOfFree
Method for the production of polyadducts of alkylene oxides... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the production of polyadducts of alkylene oxides..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the production of polyadducts of alkylene oxides... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2582914