Abstract:
Polyamides, oligomers thereof or mixtures thereof, if required with further reaction products, are prepared by reacting aminonitriles or dinitriles and diamines or a mixture containing aminonitrile, dinitrile and diamine, and, if required, further polyamide-forming monomers and/oligomers with water in a reactor (1) having a vertically oriented longitudinal axis, by a process in which, in the reactor (1), the reaction product is removed from the bottom and ammonia formed and any further low molecular weight compounds formed and water are taken off via the top (2), wherein the reactor (1) has at least two chambers (4) arranged one on top of the other in the longitudinal direction, the chambers (4) being separated from one another by liquid-tight trays (5), each chamber (4) being connected by a liquid overflow (6) to the chamber (4) directly underneath and a liquid product stream being taken off by the liquid overflow (6) of the lowermost chamber (4), the gas space (7) above the liquid level in each chamber (4) being connected to the chamber (4) arranged directly above in each case by one or more conduit pipes (8) which in each case opens or open into a gas distributor (9) having orifices (11) for gas exit below the liquid level, and comprising in each case at least one baffle plate (12) which is arranged vertically around each gas distributor (9) and whose upper end terminates below the liquid level and whose lower end terminates above the liquid-tight tray (5) of the chamber (4) and which separates each chamber (4) into one or more gassed (13) and into one or more ungassed (14) spaces.
Abstract:
Compact, transparent polyisocyanate polyaddition products are produced in a process by reacting (a) isocyanates with (b) compounds reactive to isocyanates, if desired in the presence of (c) catalysts and (d) auxiliaries and/or additives, which comprises using as (b) compounds reactive to isocyanates a mixture (i) which has an average functionality of >3 and an average hydroxyl number of from 300 to 950 mg KOH/g.
Abstract:
In a process for preparing polyisocyanate polyaddition products by reacting isocyanates with compounds which are reactive toward isocyanates, in the presence or absence of blowing agents, catalysts, auxiliaries and/or additives, the reaction is carried out in the presence of (i) particles which have a size of
Abstract:
High-functionality polyisocyanates are prepared by a process which comprises (i) preparation of an addition product (A) which contains one group which is reactive toward isocyanate and at least two isocyanate groups by reacting (a) a diisocyanate or polyisocyanate I with (b1) compounds having at least three groups which are reactive toward isocyanate or (b2) compounds containing two groups which are reactive toward isocyanate or mixtures of (b1) and (b2), where at least one of the components (a) or (b) has functional groups having differing reactivities toward the functional groups of the other component and the reaction ratio is selected so that the addition product (A) contains an average of one group which is reactive toward isocyanate, (ii) if desired, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) containing an average of one group which is reactive toward isocyanate and an average of more than two isocyanate groups, and (iii) reaction of the addition product (A) and/or the polyaddition product (P) with a diisocyanate or polyisocyanate II.
Abstract:
In a process for producing foams based on polyisocyanate polyaddition products by reacting isocyanates with compounds which are reactive toward isocyanates and have a molecular weight of from 400 to 8000 in the presence of blowing agents, catalysts and, if desired, chain extenders and/or crosslinkers having a molecular weight of 40.degree. C.
Abstract:
The present invention relates to a mixture that contains (i) at least one isocyanate and (ii) at least one organic and/or inorganic acid anhydride.
Abstract:
Polyisocyanates are prepared by a process which comprises (i) preparation of an addition product (A) which contains one group which is reactive toward isocyanate and one isocyanate group by reacting (a) a diisocyanate I with (b) compounds containing two groups which are reactive toward isocyanate, where at least one of the components (a) or (b) has functional groups having differing reactivities toward the functional groups of the other component, (ii) if desired, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) which contains one group which is reactive toward isocyanate and one isocyanate group and (iii) reaction of the addition product (A) and/or the polyaddition product (P) with a diisocyanate or polyisocyanate II which is different from diisocyanate I.
Abstract:
A crystalline multimetal cyanide complex of the formula (I) M1a[M2(CN)bL1c]d*e(M1fXg)*hL2′iH2O (I) where M1 is at least one element from the group consisting of Zn(II), Fe(II), Co(III), Ni(II), Mn(II), Co(II), Sn(II). Pb(II), Fe(III), Mo(IV), Mo(VI), Al(III), V(IV), V(V), Sr(II, W(IV), W(VI), Cu(II), and Cr(III), M2 is at least one element from the group consisting of Fe(II), Fe(III), Co(III), Cr(III), Mn(II), Mn(III), Ir(III), Rh(III), Ru(II), V(IV), V(V), Co(II) and Cr(II), L1 is at least one ligand from the group consisting of cyanide, carbonyl, cyanate, isocyanate, nitrile, thiocyanate and nitrosyl, X is a formate anion, an acetate anion or propionate anion, L2 is at least one water-miscible ligand from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, urea derivatives, amides, nitriles and sulfides, a, b, c, d, e, f, g, h, i are integers, with a, b, c and d being chosen so that the electrical neutrality condition is satisfied, and f and g being chosen so that the electrical neutrality condition is satisfied, the X-ray diffiactogram of which shows reflections at particular d values, can be employed as catalyst.
Abstract:
A process for the preparation of foamed plastics materials based on polyisocyanate polyaddition products by the reaction of isocyanates with isocyanate-reactive compounds in the presence of catalysts and, optionally, auxiliaries and/or additives, wherein i) isocyanates having isocyanurate and/or biuret structures are used, the isocyanate-reactive compounds used are ii) at least one diol and/or polyol having a molecular weight of from 400 to 8000 and containing at least 50% of primary hydroxyl groups based on all of the hydroxyl groups present in the compound, iii) at least one compound having at least one primary amine group, and diols and/or triols having molecular weights of less than 400 are optionally used as chain-extending and/or crosslinking agents, the reaction being carried out in the presence of iv) at least one tertiary amine acting as catalyst and/or v) at least one metal salt acting as catalyst and vi) water.
Abstract:
Compounds of the formula 1 OCN—R1—NHCOX—R2—(Y)n (1), where X is a covalent bond to R2 or is O, S or NR3, Y is a hydrogen atom or a free functional group and n is an integer from 1 to 20, can be used for functionalizing or modifying compounds or solid surfaces which have at least one group which is reactive toward isocyanate.