The Delft group

In the past, hydrogen hydrates have been difficult to produce, since they require low temperatures and pressures in the range of 36,000 psi. Working with the Colorado School of Mines, the Delft group used a promoter chemical (tetrahydrofuran) to stabilize the hydrates at 1,450 psi. This approach would allow about 120 liters (120 kilograms) of water to... 

Patterson s group [64-66] performed extensive measurements on polymer-organic solvent systems in the late 1960s and early 1970s. In the same period studies on polymer SCF systems were started [67-69], which were continued in the 1980s by the groups of Ratzsch [70-73] and Luft [75-75] and the Delft group [76-77],... 

We consider all these field tests still to be preliminary. They will have to be repeated on a larger scale and in different locations and countries before a complete picture can be gained. The work on Spodoptera exigua in Holland was done in collaboration with W.J. Nooijen of the Delft group and C. van der Kraan and S. Voermanof the Institute for Pesticide Research in Wageningen. 

The Delft group (Kapteyn, Bakker) reported for their large MFI crystals experimental values of ir range of 1.6-2.0x10" mol g whereas Vroon et... 

Separation results with supported MFI membranes of good quality are reported by the Delft group (Kapteyn, Geus, Bakker [69-71,89]) with membranes on porous steel supports and by the Twente group (Burggraaf, Vroon et al. [72,73]) with membranes on porous a-alumina support and of medium (defect quality) by, e.g., the groups of Noble and coworkers [27,77,97] on y-alumina supports, of Ma and coworkers [76,96]. Some other groups report results without sufficient indication of membrane quality [64,75,98]. 

The Delft group [46] recently reported the reductive amination of aldohexoses over Pt/C with mono- and bifunctional alkylamines. The chemical nature of the species present in solution was studied by and C NMR. When the reductive amination was conducted in the presence of ethylenediamine, the resulting product was submitted to carboxymethylation to form an EDTA (ethylenediaminetetraace-tate)-like complexing agent, with the aim of improved biodegradability (Fig. 2). The sequestering capacity of such compounds was also investigated. 

The Delft synthesis makes use of an acid-catalyzed ring closure - in fact an intramolecular aromatic alkylation - of a l-(3,5-dihydroxy-4-methoxybenzyl) isoquinoline derivative that is prepared starting from (natural) gallic acid. One of the hydroxyl groups is removed via a Pd/ C hydrogenation of the benzyl ether. Other catalytic steps play an important role some steps were improved recently [27]. The crucial step in the Rice synthesis makes use of a l-(2-bromo-5-hydroxy-4-methoxybenzyl)isoquinoline derivative that is also cyclized in an acid-catalyzed ring closure to the morphinan skeleton, followed by catalytic removal of the bromo substituent (Scheme 5.8). 

A useful introduction of the 14-hydroxyl substituent by co-catalyzed oxidation of certain morphine derivatives with air (oxygen) has been patented by Linders, a former student of the Delft alkaloid group, and Vrijhof (Organon/Diosynth) [29]. 

The reference group for Seville is comprised of six samples previously classified as Sevillan productions by XRF and four new samples that were not previously analyzed. It is essential to point out that one of the latter sherds is typologically classified as a Delft product. 

Figure 3.5. Effect of the nature of the side group on the secondary glass transition (J. Heijboer, Mechanical properties of glassy polymers containing saturated rings, dissertation RU-Leiden, Waltman, Delft, 1972).

Thiourea inclusion complexes. As noted in the second paragraph beginning on 1, 1165, a Delft group (Verkade et al.s) reported an efficient separation of cis-and trarcs-4-isopropylcyclohexane-l-carboxylic acid based on their observation that the trans-acid forms a thiourea inclusion complex whereas the cis isomer does not. However, they failed to account for the difference. A simple explanation became... 

Although this abbreviated survey could stress only some of the most important points, the author has taken the opportunity to incorporate some brief remarks on the recent results obtained by his research group at Delft University and on the catalyst research group of the Central Laboratory of the Staatsmijnen at Geleen (the Netherlands). He wishes to express his sincere thanks to Mr. P. Zwietering of the latter group for his assistance in preparing this review. 

The synthetic challenge centred around the issue that a -lactam ring is more easily hydrolysed than a normal amide. For a selective hydrolysis, special reaction conditions are required, which differentiate between secondary and tertiary amides. Additionally, the carboxy group must be protected before hand. DSM developed a particular process for this, calling it Delft cleavage . Nowadays, the reaction can be carried out in an intrinsically more elegant way with the known penicillin-acylase, which however, in contrast to earlier methods, is now immobilised (Tab. 5.4). [49]... 

Luvara G, Pickering S, et al (2010) Risk evaluation industrial use of PFOA and PFOS Report of the RPS Group. Delft, Netherlands... 

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